[compiler-rt][ubsan] Split Implicit Integer Truncation Sanitizer into unsigned and signed checks

[lebedev.ri]

Summary

This is compiler-rt part.
clang part is D50901.

[lebedev.ri]

Rebased, should be NFC.

[lebedev.ri]

ping.

[lebedev.ri]

Ping.

[lebedev.ri]

Ping once again :)

[lebedev.ri]

@vsk / @filcab - ping.
Assuming the clang part gets accepted, is this OK?

[vitalybuka]

test/ubsan/TestCases/ImplicitConversion/integer-truncation.c

96 ↗

(On Diff #162041)

Could you please split refactoring and behavior changes into separate patches?

[lebedev.ri]

test/ubsan/TestCases/ImplicitConversion/integer-truncation.c

96 ↗

(On Diff #162041)

I'm not sure i follow.
By refactoring you mean the test rewrite?

[lebedev.ri]

• Split off the NFC preparatory changes.
• Rebased.
• Drop legacy handling

test/ubsan/TestCases/ImplicitConversion/integer-truncation.c

96 ↗

(On Diff #162041)

Hopefully this is better.

[filcab]

lib/ubsan/ubsan_handlers.h

128–130

We did release an llvm version with that kind, though.

Can you re-add it, with an "... (un)signed..." in the error message (or something better, of course), so we still support files compiled with an older (but released) compiler, please?

test/ubsan/TestCases/ImplicitConversion/signed-integer-truncation-summary.cpp

11

Can't we simply not test on the SUMMARY line (test on the error line) and allow standalone too? I don't see what we gain by restricting the test.

[lebedev.ri]

Thank you for taking a look!

lib/ubsan/ubsan_handlers.h

128–130

@filcab @vitalybuka
https://reviews.llvm.org/D50901#inline-462927

vitalybuka
I don't think we try support mismatched versions of clang and compiler-rt

Please make up your mind :)
Do we or don't we?

(If we do, i can just reinstate all that shiny upgrade logic, which is fully-functional)

[filcab]

lib/ubsan/ubsan_handlers.h

128–130

We don't have a "we should always be backwards compatible" rule, or anything close to it. The llvm releases don't promise to keep the sanitizers backwards compatible.

*But*, as I mentioned on the clang part, we have, in the past, tried to keep compatibility if it's simple and easy. Otherwise, having a linker error helps avoiding surprising runtime error messages when there's a mix of objects from different versions (which can happen anyway. Would be nice on our part to not make it worse :-) ).
Example of maintaining backwards compat: https://reviews.llvm.org/D11793
Example of changing the ABI + revving up the number so we get linker errors when mixing: https://reviews.llvm.org/D28244

In this case, we can have one of these solutions:

• Keep backwards compatibility by supporting the older enum value, at the expense of 2 or 3 lines of code.
• Rev up the version number for an ABI break, "just" so we can re-use that value (no savings in struct size or anything)
• Silently re-use that value and possibly issuing the wrong signed/unsigned message if there is a mix

I think the expense of supporting the first case is not enough to make us pick one of the other two.

Thank you,
Filipe

[lebedev.ri]

lib/ubsan/ubsan_handlers.h

128–130

I think the expense of supporting the first case is not enough to make us pick one of the other two.

I agree with this. That is why i have implemented that very solution in the initial version of this review.
@vitalybuka do i return that code?

[vitalybuka]

lib/ubsan/ubsan_handlers.h

128–130

I think if we do not support backward comparability, we should not to even try to pretend to avoid confusion, even if it's trivial like here. However I am not strong about it. So up to you and @filcab

[lebedev.ri]

• Rebased
• Tentatively restored the legacy (ICCK_IntegerTruncation) handling, pending @filcab's decision.

[filcab]

Thanks for working on this,
Filipe

lib/ubsan/ubsan_handlers.cc

468

If we can unambiguously know which type of error we should emit, why not have the clang change, but always emit the ICCK_IntegerTruncation check type? Then we'd only get this small chunk of code added to compiler-rt.

lib/ubsan/ubsan_handlers.h

128–130

Mention that only clang7.0 emitted this. Then we'll know we can get rid of it if we rev up the check version (breaking the ABI anyway).

[lebedev.ri]

lib/ubsan/ubsan_handlers.cc

468

I think it shifts/duplicates the responsibilities.
At the time of the call void @__ubsan_handle_implicit_conversion we already *know* the kind.
If we pass some generic kind, we will then have to re-figure it out here in compiler-rt.
And both the places will need to be kept in sync.
And double the attention needs to be paid to the tests.
I'd honestly better emit ErrorType::GenericUB in place of ICCK_IntegerTruncation instead of not passing the right kind..

[filcab]

0 only means “one of those two”, so I prefer your current patch then a
change to genericUB.

Your reasoning is good, and I’m ok with having different constants. Current
patch almost LGTM:

• I have questions about the tests and why not support the standalone

runtime.

• please add a mention that the 0 enumerator for the check kind was only

emitted on llvm7.0

Thank you,
Filipe

[lebedev.ri]

In D50902#1250110, @filcab wrote:

0 only means “one of those two”, so I prefer your current patch then a
change to genericUB.

Your reasoning is good, and I’m ok with having different constants.

Great to hear!

Current patch almost LGTM:

• I have questions about the tests and why not support the standalone

runtime.

Hm, i'm not sure what you mean.
This should support all the same things as the current monolithic Kind.

• please add a mention that the 0 enumerator for the check kind was only

emitted on llvm7.0

Yes, i will do that. I didn'd actually post the updated patch yet, i will.

Thank you,
Filipe

[lebedev.ri]

As requested in https://reviews.llvm.org/D50902#1250110, actually document that ICCK_IntegerTruncation was only emitted by clang 7.

test/ubsan/TestCases/ImplicitConversion/signed-integer-truncation-summary.cpp

11

That summary line is the very essence of what we are checking in this test.
We can only do that in non-standalone builds, because standalone builds only print generic undefined-behavior error name, while ubsan is coupled with some other sanitizer, an actual error name is printed.
We have discussed this with you in https://reviews.llvm.org/D48959#inline-429528

[lebedev.ri]

Ping! It seemed we were so close here :)

[filcab]

Very sorry for the delay, and especially sorry for asking about the same thing over and over :|
Thanks for your patience,

LGTM

[lebedev.ri]

In D50902#1260511, @filcab wrote:

Very sorry for the delay, and especially sorry for asking about the same thing over and over :|
Thanks for your patience,

LGTM

Yay! Thank you for the review very much :)
1 is a go, 3 left...

lib/ubsan/ubsan_checks.inc

 UBSAN_CHECK(SignedIntegerOverflow, "signed-integer-overflow",
             "signed-integer-overflow")
 UBSAN_CHECK(UnsignedIntegerOverflow, "unsigned-integer-overflow",
             "unsigned-integer-overflow")
 UBSAN_CHECK(IntegerDivideByZero, "integer-divide-by-zero",
             "integer-divide-by-zero")
 UBSAN_CHECK(FloatDivideByZero, "float-divide-by-zero", "float-divide-by-zero")
 UBSAN_CHECK(InvalidBuiltin, "invalid-builtin-use", "invalid-builtin-use")
-UBSAN_CHECK(ImplicitIntegerTruncation, "implicit-integer-truncation",
-            "implicit-integer-truncation")
+UBSAN_CHECK(ImplicitUnsignedIntegerTruncation,
+            "implicit-unsigned-integer-truncation",
+            "implicit-unsigned-integer-truncation")
+UBSAN_CHECK(ImplicitSignedIntegerTruncation,
+            "implicit-signed-integer-truncation",
+            "implicit-signed-integer-truncation")
 UBSAN_CHECK(InvalidShiftBase, "invalid-shift-base", "shift-base")
 UBSAN_CHECK(InvalidShiftExponent, "invalid-shift-exponent", "shift-exponent")
 UBSAN_CHECK(OutOfBoundsIndex, "out-of-bounds-index", "bounds")
 UBSAN_CHECK(UnreachableCall, "unreachable-call", "unreachable")
 UBSAN_CHECK(MissingReturn, "missing-return", "return")
 UBSAN_CHECK(NonPositiveVLAIndex, "non-positive-vla-index", "vla-bound")
 UBSAN_CHECK(FloatCastOverflow, "float-cast-overflow", "float-cast-overflow")
 UBSAN_CHECK(InvalidBoolLoad, "invalid-bool-load", "bool")
 UBSAN_CHECK(InvalidEnumLoad, "invalid-enum-load", "enum")
 UBSAN_CHECK(FunctionTypeMismatch, "function-type-mismatch", "function")
 UBSAN_CHECK(InvalidNullReturn, "invalid-null-return",
             "returns-nonnull-attribute")
 UBSAN_CHECK(InvalidNullArgument, "invalid-null-argument", "nonnull-attribute")
 UBSAN_CHECK(DynamicTypeMismatch, "dynamic-type-mismatch", "vptr")
 UBSAN_CHECK(CFIBadType, "cfi-bad-type", "cfi")

lib/ubsan/ubsan_handlers.h

 };
 
 /// \brief Handle a load of an invalid value for the type.
 RECOVERABLE(load_invalid_value, InvalidValueData *Data, ValueHandle Val)
 
 /// Known implicit conversion check kinds.
 /// Keep in sync with the enum of the same name in CGExprScalar.cpp
 enum ImplicitConversionCheckKind : unsigned char {
-  ICCK_IntegerTruncation = 0,
+  ICCK_IntegerTruncation = 0, // Legacy, was only used by clang 7.
+  ICCK_UnsignedIntegerTruncation = 1,
+  ICCK_SignedIntegerTruncation = 2,
 };
 
 struct ImplicitConversionData {
   SourceLocation Loc;
   const TypeDescriptor &FromType;
   const TypeDescriptor &ToType;
   /* ImplicitConversionCheckKind */ unsigned char Kind;
 };

lib/ubsan/ubsan_handlers.cc

 }
 
 static void handleImplicitConversion(ImplicitConversionData *Data,
                                      ReportOptions Opts, ValueHandle Src,
                                      ValueHandle Dst) {
   SourceLocation Loc = Data->Loc.acquire();
   ErrorType ET = ErrorType::GenericUB;
 
+  const TypeDescriptor &SrcTy = Data->FromType;
+  const TypeDescriptor &DstTy = Data->ToType;
+
+  bool SrcSigned = SrcTy.isSignedIntegerTy();
+  bool DstSigned = DstTy.isSignedIntegerTy();
+
   switch (Data->Kind) {
-  case ICCK_IntegerTruncation:
-    ET = ErrorType::ImplicitIntegerTruncation;
+  case ICCK_IntegerTruncation: { // Legacy, no longer used.
+    // Let's figure out what it should be as per the new types, and upgrade.
+    // If both types are unsigned, then it's an unsigned truncation.
+    // Else, it is a signed truncation.
+    if (!SrcSigned && !DstSigned) {
+      ET = ErrorType::ImplicitUnsignedIntegerTruncation;
+    } else {
+      ET = ErrorType::ImplicitSignedIntegerTruncation;
+    }
+    break;
+  }
+  case ICCK_UnsignedIntegerTruncation:
+    ET = ErrorType::ImplicitUnsignedIntegerTruncation;
+    break;
+  case ICCK_SignedIntegerTruncation:
+    ET = ErrorType::ImplicitSignedIntegerTruncation;
     break;
   }
 
   if (ignoreReport(Loc, Opts, ET))
     return;
 
-  const TypeDescriptor &SrcTy = Data->FromType;
-  const TypeDescriptor &DstTy = Data->ToType;
-
   ScopedReport R(Opts, Loc, ET);
 
   // FIXME: is it possible to dump the values as hex with fixed width?
 
   Diag(Loc, DL_Error, ET,
        "implicit conversion from type %0 of value %1 (%2-bit, %3signed) to "
        "type %4 changed the value to %5 (%6-bit, %7signed)")
       << SrcTy << Value(SrcTy, Src) << SrcTy.getIntegerBitWidth()
-      << (SrcTy.isSignedIntegerTy() ? "" : "un") << DstTy << Value(DstTy, Dst)
-      << DstTy.getIntegerBitWidth() << (DstTy.isSignedIntegerTy() ? "" : "un");
+      << (SrcSigned ? "" : "un") << DstTy << Value(DstTy, Dst)
+      << DstTy.getIntegerBitWidth() << (DstSigned ? "" : "un");
 }
 
 void __ubsan::__ubsan_handle_implicit_conversion(ImplicitConversionData *Data,
                                                  ValueHandle Src,
                                                  ValueHandle Dst) {
   GET_REPORT_OPTIONS(false);
   handleImplicitConversion(Data, Opts, Src, Dst);
 }

test/fuzzer/ImplicitIntegerTruncationTest.cpp

-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-
-// Test for signed-integer-overflow.
-#include <assert.h>
-#include <climits>
-#include <cstddef>
-#include <cstdint>
-#include <cstdlib>
-#include <iostream>
-
-static volatile int Sink;
-static unsigned char Large = UINT8_MAX;
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-  assert(Data);
-  if (Size > 0 && Data[0] == 'H') {
-    Sink = 1;
-    if (Size > 1 && Data[1] == 'i') {
-      Sink = 2;
-      if (Size > 2 && Data[2] == '!') {
-        Large = Large + 1;  // 'char overflow'.
-      }
-    }
-  }
-  return 0;
-}

test/fuzzer/ImplicitSignedIntegerTruncationTest.cpp

+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for signed-integer-overflow.
+#include <assert.h>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+
+static volatile int Sink;
+static unsigned char Large = UINT8_MAX;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        Large = Large + 1;  // 'char overflow'.
+      }
+    }
+  }
+  return 0;
+}

test/fuzzer/ImplicitUnsignedIntegerTruncationTest.cpp

+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for unsigned-integer-overflow.
+#include <assert.h>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+
+static volatile int Sink;
+static unsigned char Large = UINT8_MAX;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        Large = (unsigned int)Large + 1U;  // 'char overflow'.
+      }
+    }
+  }
+  return 0;
+}

test/fuzzer/fuzzer-implicit-integer-truncation.test

-RUN: rm -f %t-ImplicitIntegerTruncationTest-Ubsan
-RUN: %cpp_compiler -fsanitize=implicit-integer-truncation -fno-sanitize-recover=all %S/ImplicitIntegerTruncationTest.cpp -o %t-ImplicitIntegerTruncationTest-Ubsan
-RUN: not %run %t-ImplicitIntegerTruncationTest-Ubsan 2>&1 | FileCheck %s
-CHECK: ImplicitIntegerTruncationTest.cpp:22:17: runtime error: implicit conversion from type 'int' of value 256 (32-bit, signed) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
-CHECK: Test unit written to ./crash-

test/fuzzer/fuzzer-implicit-signed-integer-truncation.test

+RUN: rm -f %t-ImplicitSignedIntegerTruncationTest-Ubsan
+RUN: %cpp_compiler -fsanitize=implicit-signed-integer-truncation -fno-sanitize-recover=all %S/ImplicitSignedIntegerTruncationTest.cpp -o %t-ImplicitSignedIntegerTruncationTest-Ubsan
+RUN: not %run %t-ImplicitSignedIntegerTruncationTest-Ubsan 2>&1 | FileCheck %s
+CHECK: ImplicitSignedIntegerTruncationTest.cpp:22:17: runtime error: implicit conversion from type 'int' of value 256 (32-bit, signed) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
+CHECK: Test unit written to ./crash-

test/fuzzer/fuzzer-implicit-unsigned-integer-truncation.test

+RUN: rm -f %t-ImplicitUnsignedIntegerTruncationTest-Ubsan
+RUN: %cpp_compiler -fsanitize=implicit-unsigned-integer-truncation -fno-sanitize-recover=all %S/ImplicitUnsignedIntegerTruncationTest.cpp -o %t-ImplicitUnsignedIntegerTruncationTest-Ubsan
+RUN: not %run %t-ImplicitUnsignedIntegerTruncationTest-Ubsan 2>&1 | FileCheck %s
+CHECK: ImplicitUnsignedIntegerTruncationTest.cpp:22:17: runtime error: implicit conversion from type 'unsigned int' of value 256 (32-bit, unsigned) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
+CHECK: Test unit written to ./crash-

test/ubsan/TestCases/ImplicitConversion/integer-truncation-blacklist.c

-// FIXME: https://code.google.com/p/address-sanitizer/issues/detail?id=316
-// I'm not sure this is actually *that* issue, but this seems oddly similar to the other XFAIL'ed cases.
-// XFAIL: android
-// UNSUPPORTED: ios
-
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
-
-// RUN: rm -f %tmp
-// RUN: echo "[implicit-integer-truncation]" >> %tmp
-// RUN: echo "fun:implicitTruncation" >> %tmp
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
-// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
-
-unsigned char implicitTruncation(unsigned int argc) {
-  return argc; // BOOM
-// CHECK: {{.*}}integer-truncation-blacklist.c:[[@LINE-1]]:10: runtime error: implicit conversion from type 'unsigned int' of value 4294967295 (32-bit, unsigned) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
-}
-
-int main(int argc, char **argv) {
-  return implicitTruncation(~0U);
-}

test/ubsan/TestCases/ImplicitConversion/integer-truncation-summary.cpp

-// RUN: %clangxx -fsanitize=implicit-integer-truncation %s -o %t
-// RUN: %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NOTYPE
-// RUN: %env_ubsan_opts=report_error_type=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-TYPE
-// REQUIRES: !ubsan-standalone && !ubsan-standalone-static
-
-#include <stdint.h>
-
-int main() {
-  uint8_t t0 = (~(uint32_t(0)));
-  // CHECK-NOTYPE: SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior {{.*}}summary.cpp:[[@LINE-1]]:16
-  // CHECK-TYPE: SUMMARY: UndefinedBehaviorSanitizer: implicit-integer-truncation {{.*}}summary.cpp:[[@LINE-2]]:16
-  return 0;
-}

test/ubsan/TestCases/ImplicitConversion/signed-integer-truncation-blacklist.c

+// FIXME: https://code.google.com/p/address-sanitizer/issues/detail?id=316
+// I'm not sure this is actually *that* issue, but this seems oddly similar to the other XFAIL'ed cases.
+// XFAIL: android
+// UNSUPPORTED: ios
+
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+
+// RUN: rm -f %tmp
+// RUN: echo "[integer]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-conversion]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-signed-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-unsigned-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+unsigned char implicitUnsignedTruncation(signed int argc) {
+  return argc; // BOOM
+// CHECK: {{.*}}signed-integer-truncation-blacklist.c:[[@LINE-1]]:10: runtime error: implicit conversion from type 'int' of value -1 (32-bit, signed) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
+}
+
+int main(int argc, char **argv) {
+  return implicitUnsignedTruncation(-1);
+}

test/ubsan/TestCases/ImplicitConversion/signed-integer-truncation-summary.cpp

+// RUN: %clangxx -fsanitize=implicit-signed-integer-truncation %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NOTYPE
+// RUN: %env_ubsan_opts=report_error_type=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-TYPE
+// REQUIRES: !ubsan-standalone && !ubsan-standalone-static
+
+#include <stdint.h>
+
+int main() {
+  uint8_t t0 = int32_t(-1);
+  // CHECK-NOTYPE: SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior {{.*}}summary.cpp:[[@LINE-1]]:16
+  // CHECK-TYPE: SUMMARY: UndefinedBehaviorSanitizer: implicit-signed-integer-truncation {{.*}}summary.cpp:[[@LINE-2]]:16
+  return 0;
+}

test/ubsan/TestCases/ImplicitConversion/signed-integer-truncation.c

+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV0 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V0
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV1 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V1
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV2 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V2
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV3 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V3
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV4 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V4
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV5 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V5
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV6 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V6
+// RUN: %clang   -x c   -fsanitize=implicit-signed-integer-truncation %s -DV7 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V7
+
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV0 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V0
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV1 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V1
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV2 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V2
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV3 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V3
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV4 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V4
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV5 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V5
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV6 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V6
+// RUN: %clang   -x c++ -fsanitize=implicit-signed-integer-truncation %s -DV7 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V7
+
+#include <stdint.h>
+
+// Test plan:
+//  * Two types - int and char
+//  * Two signs - signed and unsigned
+//  * Square that - we have input and output types.
+// Thus, there are total of (2*2)^2 == 16 tests.
+// These are all the possible variations/combinations of casts.
+// However, not all of them should result in the check.
+// So here, we *only* check which should and which should not result in checks.
+
+unsigned int convert_unsigned_int_to_unsigned_int(unsigned int x) {
+#line 100
+  return x;
+}
+
+unsigned char convert_unsigned_char_to_unsigned_char(unsigned char x) {
+#line 200
+  return x;
+}
+
+signed int convert_signed_int_to_signed_int(signed int x) {
+#line 300
+  return x;
+}
+
+signed char convert_signed_char_to_signed_char(signed char x) {
+#line 400
+  return x;
+}
+
+unsigned char convert_unsigned_int_to_unsigned_char(unsigned int x) {
+#line 500
+  return x;
+}
+
+unsigned int convert_unsigned_char_to_unsigned_int(unsigned char x) {
+#line 600
+  return x;
+}
+
+signed int convert_unsigned_char_to_signed_int(unsigned char x) {
+#line 700
+  return x;
+}
+
+signed int convert_signed_char_to_signed_int(signed char x) {
+#line 800
+  return x;
+}
+
+signed int convert_unsigned_int_to_signed_int(unsigned int x) {
+#line 900
+  return x;
+}
+
+unsigned int convert_signed_int_to_unsigned_int(signed int x) {
+#line 1000
+  return x;
+}
+
+unsigned char convert_signed_int_to_unsigned_char(signed int x) {
+#line 1100
+  return x;
+}
+
+unsigned char convert_signed_char_to_unsigned_char(signed char x) {
+#line 1200
+  return x;
+}
+
+signed char convert_unsigned_char_to_signed_char(unsigned char x) {
+#line 1300
+  return x;
+}
+
+unsigned int convert_signed_char_to_unsigned_int(signed char x) {
+#line 1400
+  return x;
+}
+
+signed char convert_unsigned_int_to_signed_char(unsigned int x) {
+#line 1500
+  return x;
+}
+
+signed char convert_signed_int_to_signed_char(signed int x) {
+#line 1600
+  return x;
+}
+
+#line 1111 // !!!
+
+int main() {
+  // No bits set.
+  convert_unsigned_int_to_unsigned_int(0);
+  convert_unsigned_char_to_unsigned_char(0);
+  convert_signed_int_to_signed_int(0);
+  convert_signed_char_to_signed_char(0);
+  convert_unsigned_int_to_unsigned_char(0);
+  convert_unsigned_char_to_unsigned_int(0);
+  convert_unsigned_char_to_signed_int(0);
+  convert_signed_char_to_signed_int(0);
+  convert_unsigned_int_to_signed_int(0);
+  convert_signed_int_to_unsigned_int(0);
+  convert_signed_int_to_unsigned_char(0);
+  convert_signed_char_to_unsigned_char(0);
+  convert_unsigned_char_to_signed_char(0);
+  convert_signed_char_to_unsigned_int(0);
+  convert_unsigned_int_to_signed_char(0);
+  convert_signed_int_to_signed_char(0);
+
+  // One lowest bit set.
+  convert_unsigned_int_to_unsigned_int(1);
+  convert_unsigned_char_to_unsigned_char(1);
+  convert_signed_int_to_signed_int(1);
+  convert_signed_char_to_signed_char(1);
+  convert_unsigned_int_to_unsigned_char(1);
+  convert_unsigned_char_to_unsigned_int(1);
+  convert_unsigned_char_to_signed_int(1);
+  convert_signed_char_to_signed_int(1);
+  convert_unsigned_int_to_signed_int(1);
+  convert_signed_int_to_unsigned_int(1);
+  convert_signed_int_to_unsigned_char(1);
+  convert_signed_char_to_unsigned_char(1);
+  convert_unsigned_char_to_signed_char(1);
+  convert_signed_char_to_unsigned_int(1);
+  convert_unsigned_int_to_signed_char(1);
+  convert_signed_int_to_signed_char(1);
+
+#if defined(V0)
+  // All source bits set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)UINT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)UINT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)UINT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)UINT32_MAX);
+  convert_unsigned_char_to_unsigned_int((uint8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)UINT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)UINT32_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)UINT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)UINT32_MAX);
+// CHECK-V0: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value -1 (32-bit, signed) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)UINT32_MAX);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)UINT32_MAX);
+#elif defined(V1)
+   // Source 'Sign' bit set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)INT32_MIN);
+  convert_signed_char_to_signed_char((int8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((uint32_t)INT32_MIN);
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)INT32_MIN);
+// CHECK-V1: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value -2147483648 (32-bit, signed) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((uint32_t)INT32_MIN);
+// CHECK-V1: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483648 (32-bit, unsigned) to type 'signed char' changed the value to 0 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)INT32_MIN);
+// CHECK-V1: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value -2147483648 (32-bit, signed) to type 'signed char' changed the value to 0 (8-bit, signed)
+#elif defined(V2)
+  // All bits except the source 'Sign' bit are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)INT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)INT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)INT32_MAX);
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)INT32_MAX);
+// CHECK-V2: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value 2147483647 (32-bit, signed) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)INT32_MAX);
+// CHECK-V2: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483647 (32-bit, unsigned) to type 'signed char' changed the value to -1 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)INT32_MAX);
+// CHECK-V2: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value 2147483647 (32-bit, signed) to type 'signed char' changed the value to -1 (8-bit, signed)
+#elif defined(V3)
+  // All destination bits set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)UINT8_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)UINT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_char_to_signed_char((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)UINT8_MAX);
+  convert_unsigned_char_to_unsigned_int((uint8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)UINT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)UINT8_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_char((int8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)UINT8_MAX);
+// CHECK-V3: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 255 (32-bit, unsigned) to type 'signed char' changed the value to -1 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)UINT8_MAX);
+// CHECK-V3: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value 255 (32-bit, signed) to type 'signed char' changed the value to -1 (8-bit, signed)
+#elif defined(V4)
+  // Destination 'sign' bit set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((uint32_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_unsigned_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((uint32_t)(uint8_t)INT8_MIN);
+// CHECK-V4: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 128 (32-bit, unsigned) to type 'signed char' changed the value to -128 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+// CHECK-V4: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value 128 (32-bit, signed) to type 'signed char' changed the value to -128 (8-bit, signed)
+#elif defined(V5)
+  // All bits except the destination 'sign' bit are set.
+  convert_unsigned_int_to_unsigned_int((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_unsigned_char_to_unsigned_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_char_to_signed_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_unsigned_char_to_unsigned_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_unsigned_int((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_unsigned_char((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V5: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value -129 (32-bit, signed) to type 'unsigned char' changed the value to 127 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((~((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V5: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 4294967167 (32-bit, unsigned) to type 'signed char' changed the value to 127 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V5: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value -129 (32-bit, signed) to type 'signed char' changed the value to 127 (8-bit, signed)
+#elif defined(V6)
+  // Only the source and destination sign bits are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)INT32_MIN);
+  convert_signed_char_to_signed_char((int8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN));
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V6: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value -2147483520 (32-bit, signed) to type 'unsigned char' changed the value to 128 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V6: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483776 (32-bit, unsigned) to type 'signed char' changed the value to -128 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V6: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value -2147483520 (32-bit, signed) to type 'signed char' changed the value to -128 (8-bit, signed)
+#elif defined(V7)
+  // All bits except the source and destination sign bits are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)INT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)INT8_MAX);
+  convert_unsigned_int_to_unsigned_char(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN))));
+// CHECK-V7: {{.*}}signed-integer-truncation.c:1100:10: runtime error: implicit conversion from type 'int' of value 2147483519 (32-bit, signed) to type 'unsigned char' changed the value to 127 (8-bit, unsigned)
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_char(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V7: {{.*}}signed-integer-truncation.c:1500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483519 (32-bit, unsigned) to type 'signed char' changed the value to 127 (8-bit, signed)
+  convert_signed_int_to_signed_char((int32_t)~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V7: {{.*}}signed-integer-truncation.c:1600:10: runtime error: implicit conversion from type 'int' of value 2147483519 (32-bit, signed) to type 'signed char' changed the value to 127 (8-bit, signed)
+#else
+#error Some V* needs to be defined!
+#endif
+
+  return 0;
+}

test/ubsan/TestCases/ImplicitConversion/unsigned-integer-truncation-blacklist.c

+// FIXME: https://code.google.com/p/address-sanitizer/issues/detail?id=316
+// I'm not sure this is actually *that* issue, but this seems oddly similar to the other XFAIL'ed cases.
+// XFAIL: android
+// UNSUPPORTED: ios
+
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation                           -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion"
+
+// RUN: rm -f %tmp
+// RUN: echo "[integer]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-conversion]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-unsigned-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | not FileCheck %s
+
+// RUN: rm -f %tmp
+// RUN: echo "[implicit-signed-integer-truncation]" >> %tmp
+// RUN: echo "fun:implicitUnsignedTruncation" >> %tmp
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang -fsanitize=implicit-integer-truncation -fno-sanitize-recover=implicit-integer-truncation -fsanitize-blacklist=%tmp -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+unsigned char implicitUnsignedTruncation(unsigned int argc) {
+  return argc; // BOOM
+// CHECK: {{.*}}unsigned-integer-truncation-blacklist.c:[[@LINE-1]]:10: runtime error: implicit conversion from type 'unsigned int' of value 4294967295 (32-bit, unsigned) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
+}
+
+int main(int argc, char **argv) {
+  return implicitUnsignedTruncation(~0U);
+}

test/ubsan/TestCases/ImplicitConversion/unsigned-integer-truncation-summary.cpp

+// RUN: %clangxx -fsanitize=implicit-unsigned-integer-truncation %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NOTYPE
+// RUN: %env_ubsan_opts=report_error_type=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-TYPE
+// REQUIRES: !ubsan-standalone && !ubsan-standalone-static
+
+#include <stdint.h>
+
+int main() {
+  uint8_t t0 = (~(uint32_t(0)));
+  // CHECK-NOTYPE: SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior {{.*}}summary.cpp:[[@LINE-1]]:16
+  // CHECK-TYPE: SUMMARY: UndefinedBehaviorSanitizer: implicit-unsigned-integer-truncation {{.*}}summary.cpp:[[@LINE-2]]:16
+  return 0;
+}

test/ubsan/TestCases/ImplicitConversion/unsigned-integer-truncation.c

+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV0 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V0
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV1 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V1
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV2 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V2
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV3 -o %t && %run %t 2>&1 | not FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V3
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV4 -o %t && %run %t 2>&1 | not FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V4
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV5 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V5
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV6 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V6
+// RUN: %clang   -x c   -fsanitize=implicit-unsigned-integer-truncation %s -DV7 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V7
+
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV0 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V0
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV1 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V1
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV2 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V2
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV3 -o %t && %run %t 2>&1 | not FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V3
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV4 -o %t && %run %t 2>&1 | not FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V4
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV5 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V5
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV6 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V6
+// RUN: %clang   -x c++ -fsanitize=implicit-unsigned-integer-truncation %s -DV7 -o %t && %run %t 2>&1 | FileCheck %s --implicit-check-not="implicit conversion" --check-prefixes=CHECK-V7
+
+#include <stdint.h>
+
+// Test plan:
+//  * Two types - int and char
+//  * Two signs - signed and unsigned
+//  * Square that - we have input and output types.
+// Thus, there are total of (2*2)^2 == 16 tests.
+// These are all the possible variations/combinations of casts.
+// However, not all of them should result in the check.
+// So here, we *only* check which should and which should not result in checks.
+
+unsigned int convert_unsigned_int_to_unsigned_int(unsigned int x) {
+#line 100
+  return x;
+}
+
+unsigned char convert_unsigned_char_to_unsigned_char(unsigned char x) {
+#line 200
+  return x;
+}
+
+signed int convert_signed_int_to_signed_int(signed int x) {
+#line 300
+  return x;
+}
+
+signed char convert_signed_char_to_signed_char(signed char x) {
+#line 400
+  return x;
+}
+
+unsigned char convert_unsigned_int_to_unsigned_char(unsigned int x) {
+#line 500
+  return x;
+}
+
+unsigned int convert_unsigned_char_to_unsigned_int(unsigned char x) {
+#line 600
+  return x;
+}
+
+signed int convert_unsigned_char_to_signed_int(unsigned char x) {
+#line 700
+  return x;
+}
+
+signed int convert_signed_char_to_signed_int(signed char x) {
+#line 800
+  return x;
+}
+
+signed int convert_unsigned_int_to_signed_int(unsigned int x) {
+#line 900
+  return x;
+}
+
+unsigned int convert_signed_int_to_unsigned_int(signed int x) {
+#line 1000
+  return x;
+}
+
+unsigned char convert_signed_int_to_unsigned_char(signed int x) {
+#line 1100
+  return x;
+}
+
+unsigned char convert_signed_char_to_unsigned_char(signed char x) {
+#line 1200
+  return x;
+}
+
+signed char convert_unsigned_char_to_signed_char(unsigned char x) {
+#line 1300
+  return x;
+}
+
+unsigned int convert_signed_char_to_unsigned_int(signed char x) {
+#line 1400
+  return x;
+}
+
+signed char convert_unsigned_int_to_signed_char(unsigned int x) {
+#line 1500
+  return x;
+}
+
+signed char convert_signed_int_to_signed_char(signed int x) {
+#line 1600
+  return x;
+}
+
+#line 1111 // !!!
+
+int main() {
+  // No bits set.
+  convert_unsigned_int_to_unsigned_int(0);
+  convert_unsigned_char_to_unsigned_char(0);
+  convert_signed_int_to_signed_int(0);
+  convert_signed_char_to_signed_char(0);
+  convert_unsigned_int_to_unsigned_char(0);
+  convert_unsigned_char_to_unsigned_int(0);
+  convert_unsigned_char_to_signed_int(0);
+  convert_signed_char_to_signed_int(0);
+  convert_unsigned_int_to_signed_int(0);
+  convert_signed_int_to_unsigned_int(0);
+  convert_signed_int_to_unsigned_char(0);
+  convert_signed_char_to_unsigned_char(0);
+  convert_unsigned_char_to_signed_char(0);
+  convert_signed_char_to_unsigned_int(0);
+  convert_unsigned_int_to_signed_char(0);
+  convert_signed_int_to_signed_char(0);
+
+  // One lowest bit set.
+  convert_unsigned_int_to_unsigned_int(1);
+  convert_unsigned_char_to_unsigned_char(1);
+  convert_signed_int_to_signed_int(1);
+  convert_signed_char_to_signed_char(1);
+  convert_unsigned_int_to_unsigned_char(1);
+  convert_unsigned_char_to_unsigned_int(1);
+  convert_unsigned_char_to_signed_int(1);
+  convert_signed_char_to_signed_int(1);
+  convert_unsigned_int_to_signed_int(1);
+  convert_signed_int_to_unsigned_int(1);
+  convert_signed_int_to_unsigned_char(1);
+  convert_signed_char_to_unsigned_char(1);
+  convert_unsigned_char_to_signed_char(1);
+  convert_signed_char_to_unsigned_int(1);
+  convert_unsigned_int_to_signed_char(1);
+  convert_signed_int_to_signed_char(1);
+
+#if defined(V0)
+  // All source bits set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)UINT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)UINT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)UINT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)UINT32_MAX);
+// CHECK-V0: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 4294967295 (32-bit, unsigned) to type 'unsigned char' changed the value to 255 (8-bit, unsigned
+  convert_unsigned_char_to_unsigned_int((uint8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)UINT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)UINT32_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)UINT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)UINT32_MAX);
+  convert_signed_char_to_unsigned_char((int8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)UINT32_MAX);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)UINT32_MAX);
+#elif defined(V1)
+   // Source 'Sign' bit set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)INT32_MIN);
+  convert_signed_char_to_signed_char((int8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((uint32_t)INT32_MIN);
+// CHECK-V1: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483648 (32-bit, unsigned) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)INT32_MIN);
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((uint32_t)INT32_MIN);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)INT32_MIN);
+#elif defined(V2)
+  // All bits except the source 'Sign' bit are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)INT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)INT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)INT32_MAX);
+// CHECK-V2: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483647 (32-bit, unsigned) to type 'unsigned char' changed the value to 255 (8-bit, unsigned)
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)INT32_MAX);
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)INT32_MAX);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)INT32_MAX);
+#elif defined(V3)
+  // All destination bits set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)UINT8_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)UINT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_char_to_signed_char((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_unsigned_char((uint32_t)UINT8_MAX);
+  convert_unsigned_char_to_unsigned_int((uint8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)UINT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)UINT8_MAX);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_char((int8_t)UINT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)UINT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)UINT8_MAX);
+  convert_unsigned_int_to_signed_char((uint32_t)UINT8_MAX);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)UINT8_MAX);
+#elif defined(V4)
+  // Destination 'sign' bit set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((uint32_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_unsigned_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_unsigned_int((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((uint32_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_char((int32_t)(uint32_t)(uint8_t)INT8_MIN);
+#elif defined(V5)
+  // All bits except the destination 'sign' bit are set.
+  convert_unsigned_int_to_unsigned_int((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_unsigned_char_to_unsigned_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_char_to_signed_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char((~((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V5: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 4294967167 (32-bit, unsigned) to type 'unsigned char' changed the value to 127 (8-bit, unsigned)
+  convert_unsigned_char_to_unsigned_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_unsigned_int((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_unsigned_char((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_char_to_unsigned_char((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)(uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)(uint8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((~((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_signed_char((int32_t)(~((uint32_t)(uint8_t)INT8_MIN)));
+#elif defined(V6)
+  // Only the source and destination sign bits are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MIN);
+  convert_signed_int_to_signed_int((int32_t)INT32_MIN);
+  convert_signed_char_to_signed_char((int8_t)INT8_MIN);
+  convert_unsigned_int_to_unsigned_char(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN));
+// CHECK-V6: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483776 (32-bit, unsigned) to type 'unsigned char' changed the value to 128 (8-bit, unsigned)
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MIN);
+  convert_signed_char_to_signed_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_int((uint32_t)INT32_MIN);
+  convert_signed_int_to_unsigned_char((int32_t)(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MIN);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MIN);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MIN);
+  convert_unsigned_int_to_signed_char((((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_signed_char((int32_t)(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+#elif defined(V7)
+  // All bits except the source and destination sign bits are set.
+  convert_unsigned_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_unsigned_char_to_unsigned_char((uint8_t)INT8_MAX);
+  convert_signed_int_to_signed_int((int32_t)INT32_MAX);
+  convert_signed_char_to_signed_char((int8_t)INT8_MAX);
+  convert_unsigned_int_to_unsigned_char(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+// CHECK-V7: {{.*}}unsigned-integer-truncation.c:500:10: runtime error: implicit conversion from type 'unsigned int' of value 2147483519 (32-bit, unsigned) to type 'unsigned char' changed the value to 127 (8-bit, unsigned)
+  convert_unsigned_char_to_unsigned_int((uint8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_int((uint8_t)INT8_MAX);
+  convert_signed_char_to_signed_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_int((uint32_t)INT32_MAX);
+  convert_signed_int_to_unsigned_char((int32_t)(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN))));
+  convert_signed_char_to_unsigned_char((int8_t)INT8_MAX);
+  convert_unsigned_char_to_signed_char((uint8_t)INT8_MAX);
+  convert_signed_char_to_unsigned_int((int8_t)INT8_MAX);
+  convert_unsigned_int_to_signed_char(~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+  convert_signed_int_to_signed_char((int32_t)~(((uint32_t)INT32_MIN) | ((uint32_t)(uint8_t)INT8_MIN)));
+#else
+#error Some V* needs to be defined!
+#endif
+
+  return 0;
+}

test/ubsan_minimal/TestCases/implicit-integer-truncation.c

-// RUN: %clang -fsanitize=implicit-integer-truncation %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
-
-#include <stdint.h>
-
-int main() {
-// CHECK-NOT: implicit-conversion
-
-  // Negative tests. Even if they produce unexpected results, this sanitizer does not care.
-  int8_t n0 = (~((uint32_t)(0))); // ~0 -> -1, but do not warn.
-  uint8_t n2 = 128;
-  uint8_t n3 = 255;
-  // Bools do not count
-  _Bool b0 = (~((uint32_t)(0)));
-  _Bool b1 = 255;
-
-  // Explicit and-ing of bits will silence it.
-  uint8_t nc0 = ((~((uint32_t)(0))) & 255);
-
-  // Positive tests.
-  uint8_t t0 = (~((uint32_t)(0)));
-// CHECK: implicit-conversion
-// CHECK-NOT: implicit-conversion
-
-  return 0;
-}

test/ubsan_minimal/TestCases/implicit-signed-integer-truncation.c

+// RUN: %clang -fsanitize=implicit-signed-integer-truncation %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
+
+#include <stdint.h>
+
+int main() {
+// CHECK-NOT: implicit-conversion
+
+  // Negative tests. Even if they produce unexpected results, this sanitizer does not care.
+  int8_t n0 = (~((uint32_t)(0))); // ~0 -> -1, but do not warn.
+  uint8_t n2 = 128;
+  uint8_t n3 = 255;
+  // Bools do not count
+  _Bool b0 = (~((uint32_t)(0)));
+  _Bool b1 = 255;
+
+  // Explicit and-ing of bits will silence it.
+  uint8_t nc0 = ((int32_t)(-1)) & 255;
+
+  // Positive tests.
+  uint8_t t0 = (int32_t)(-1);
+// CHECK: implicit-conversion
+// CHECK-NOT: implicit-conversion
+
+  return 0;
+}

test/ubsan_minimal/TestCases/implicit-unsigned-integer-truncation.c

+// RUN: %clang -fsanitize=implicit-unsigned-integer-truncation %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
+
+#include <stdint.h>
+
+int main() {
+// CHECK-NOT: implicit-conversion
+
+  // Negative tests. Even if they produce unexpected results, this sanitizer does not care.
+  int8_t n0 = (~((uint32_t)(0))); // ~0 -> -1, but do not warn.
+  uint8_t n2 = 128;
+  uint8_t n3 = 255;
+  // Bools do not count
+  _Bool b0 = (~((uint32_t)(0)));
+  _Bool b1 = 255;
+
+  // Explicit and-ing of bits will silence it.
+  uint8_t nc0 = ((~((uint32_t)(0))) & 255);
+
+  // Positive tests.
+  uint8_t t0 = (~((uint32_t)(0)));
+// CHECK: implicit-conversion
+// CHECK-NOT: implicit-conversion
+
+  return 0;
+}