[BuildLibCalls] Add noundef to standard I/O functions

[aqjune]

Summary

This patch adds noundef to return value and arguments of standard I/O functions.
With this patch, passing undef or poison to the functions becomes undefined
behavior in LLVM IR. Since undef/poison is lowered from operations having UB in C/C++,
passing undef to them was already UB in source.

With this patch, the functions cannot return undef or poison anymore as well.
According to C17 standard, ungetc/ungetwc/fgetpos/ftell can generate unspecified
value; 3.19.3 says unspecified value is a valid value of the relevant type,
and using unspecified value is unspecified behavior, which is not UB, so it
cannot be undef (using undef is UB when e.g. it is used at branch condition).

— The value of the file position indicator after a successful call to the ungetc function for a text stream, or the ungetwc function for any stream, until all pushed-back characters are read or discarded (7.21.7.10, 7.29.3.10).
— The details of the value stored by the fgetpos function (7.21.9.1).
— The details of the value returned by the ftell function for a text stream (7.21.9.4).

In the long run, most of the functions listed in BuildLibCalls should have noundefs; to remove redundant diffs which will anyway disappear in the future, I added noundef to a few more non-I/O functions as well.

[jdoerfert]

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

509

I'd split it into noundef and other attributes. noundef is so new that we should keep that separate, having the others in a single patch is fine with me though.

[aqjune]

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

509

Hi,
These attributes existed in the past - they are copied from lines 514-515.
This change was made because noundef is not added to frexp/frexpl/frexpf in this patch, which can possibly make those unspeculatable.

[jdoerfert]

LGTM, assuming the fixes to the failing tests are straight forward.

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

509

I see.

[aqjune]

Update PR3589-freestanding-libcalls.c

[aqjune]

If things go well, I'll add noundef to other library functions such as utime, setenv, unsetenv, .... as well.
For malloc/calloc/realloc/free, I'll think more about them. I guess it is safe to tag noundef to free's operand, but for malloc I'm not 100% sure...

[jdoerfert]

In D85345#2205691, @aqjune wrote:

If things go well, I'll add noundef to other library functions such as utime, setenv, unsetenv, .... as well.
For malloc/calloc/realloc/free, I'll think more about them. I guess it is safe to tag noundef to free's operand, but for malloc I'm not 100% sure...

What I think is helpful is the operand of a free and the return value of a {m,c,re}alloc. Arguably, you can give the latter anything but what falls out is better not undef or poison ;)

[aqjune]

What about undef or poison is given to malloc? If it should raise UB, the size argument and returned pointer should be noundef.

[jdoerfert]

In D85345#2205712, @aqjune wrote:

What about undef or poison is given to malloc? If it should raise UB, the size argument and returned pointer should be noundef.

It is unclear to me if we want to forbid undef to be passed to malloc. It makes practical sense but not from a semantic perspective.
However, even if you pass undef you should not get undef back. So the return should never be undef for sure. If it doesn, how could you ever deal with it, given that a branch on the result would be UB :D

[aqjune]

In D85345#2205745, @jdoerfert wrote:

In D85345#2205712, @aqjune wrote:

What about undef or poison is given to malloc? If it should raise UB, the size argument and returned pointer should be noundef.

It is unclear to me if we want to forbid undef to be passed to malloc. It makes practical sense but not from a semantic perspective.
However, even if you pass undef you should not get undef back. So the return should never be undef for sure. If it doesn, how could you ever deal with it, given that a branch on the result would be UB :D

Makes sense.... and labeling the returned pointer of malloc as noundef will be useful in various places, e.g. proving safety of loop unswitching on icmp(malloc(p), null).
Give me some time, because I'd like to play with this by implementing this on Alive2 and see how it goes when running unit tests.

clang/test/CodeGen/PR3589-freestanding-libcalls.c

 // RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm %s -o - | grep 'declare i32 @printf' | count 1
-// RUN: %clang_cc1 -triple i386-unknown-unknown -O2 -emit-llvm %s -o - | grep 'declare i32 @puts' | count 1
-// RUN: %clang_cc1 -triple i386-unknown-unknown -ffreestanding -O2 -emit-llvm %s -o - | not grep 'declare i32 @puts'
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O2 -emit-llvm %s -o - | grep 'declare noundef i32 @puts' | count 1
+// RUN: %clang_cc1 -triple i386-unknown-unknown -ffreestanding -O2 -emit-llvm %s -o - | not grep 'declare noundef i32 @puts'
 
 int printf(const char *, ...);
 
 void f0() {
   printf("hello\n");
 }

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

 //===- BuildLibCalls.cpp - Utility builder for libcalls -------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //

 
 STATISTIC(NumReadNone, "Number of functions inferred as readnone");
 STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
 STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
 STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
 STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
 STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
 STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
+STATISTIC(NumNoUndef, "Number of function returns inferred as noundef returns");
 STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
 STATISTIC(NumReturnedArg, "Number of arguments inferred as returned");
 
 static bool setDoesNotAccessMemory(Function &F) {
   if (F.doesNotAccessMemory())
     return false;
   F.setDoesNotAccessMemory();
   ++NumReadNone;

 static bool setOnlyReadsMemory(Function &F, unsigned ArgNo) {
   if (F.hasParamAttribute(ArgNo, Attribute::ReadOnly))
     return false;
   F.addParamAttr(ArgNo, Attribute::ReadOnly);
   ++NumReadOnlyArg;
   return true;
 }
 
+static bool setRetAndArgsNoUndef(Function &F) {
+  bool Changed = false;
+  if (!F.getReturnType()->isVoidTy() &&
+      !F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoUndef)) {
+    F.addAttribute(AttributeList::ReturnIndex, Attribute::NoUndef);
+    ++NumNoUndef;
+    Changed = true;
+  }
+  for (unsigned ArgNo = 0; ArgNo < F.arg_size(); ++ArgNo) {
+    if (!F.hasParamAttribute(ArgNo, Attribute::NoUndef)) {
+      F.addParamAttr(ArgNo, Attribute::NoUndef);
+      ++NumNoUndef;
+      Changed = true;
+    }
+  }
+  return Changed;
+}
+
 static bool setRetNonNull(Function &F) {
   assert(F.getReturnType()->isPointerTy() &&
          "nonnull applies only to pointers");
   if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NonNull))
     return false;
   F.addAttribute(AttributeList::ReturnIndex, Attribute::NonNull);
   ++NumNonNull;
   return true;
case LibFunc_strpbrk:
     return Changed;
   case LibFunc_strtok:
   case LibFunc_strtok_r:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_scanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_setbuf:
   case LibFunc_setvbuf:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_strdup:
   case LibFunc_strndup:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_stat:
   case LibFunc_statvfs:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_sscanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_sprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotAlias(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_snprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotAlias(F, 0);
     Changed |= setDoesNotCapture(F, 2);
     Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_setitimer:
     Changed |= setDoesNotThrow(F);
case LibFunc_mktime:
     return Changed;
   case LibFunc_realloc:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_read:
     // May throw; "read" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_rewind:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_rmdir:
   case LibFunc_remove:
   case LibFunc_realpath:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
   case LibFunc_readlink:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_write:
     // May throw; "write" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_aligned_alloc:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_bcopy:
case LibFunc_atoll:
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_access:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_fopen:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_fdopen:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_feof:
+    Changed |= setRetAndArgsNoUndef(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
+    return Changed;
   case LibFunc_free:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
+    return Changed;
   case LibFunc_fseek:
   case LibFunc_ftell:
   case LibFunc_fgetc:
   case LibFunc_fgetc_unlocked:
   case LibFunc_fseeko:
   case LibFunc_ftello:
   case LibFunc_fileno:
   case LibFunc_fflush:
   case LibFunc_fclose:
   case LibFunc_fsetpos:
   case LibFunc_flockfile:
   case LibFunc_funlockfile:
   case LibFunc_ftrylockfile:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_ferror:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F);
     return Changed;
   case LibFunc_fputc:
   case LibFunc_fputc_unlocked:
   case LibFunc_fstat:
+    Changed |= setRetAndArgsNoUndef(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
   case LibFunc_frexp:
   case LibFunc_frexpf:
   case LibFunc_frexpl:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
   case LibFunc_fstatvfs:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_fgets:
   case LibFunc_fgets_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 2);
     return Changed;
   case LibFunc_fread:
   case LibFunc_fread_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 3);
     return Changed;
   case LibFunc_fwrite:
   case LibFunc_fwrite_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 3);
     // FIXME: readonly #1?
     return Changed;
   case LibFunc_fputs:
   case LibFunc_fputs_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_fscanf:
   case LibFunc_fprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_fgetpos:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_getc:
+    Changed |= setRetAndArgsNoUndef(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
+    return Changed;
   case LibFunc_getlogin_r:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 0);
+    return Changed;
   case LibFunc_getc_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_getenv:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_gets:
   case LibFunc_getchar:
   case LibFunc_getchar_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     return Changed;
   case LibFunc_getitimer:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_getpwnam:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_ungetc:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_uname:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_unlink:
case LibFunc_utimes:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_putc:
   case LibFunc_putc_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_puts:
   case LibFunc_printf:
   case LibFunc_perror:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_pread:
     // May throw; "pread" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_pwrite:
     // May throw; "pwrite" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_putchar:
   case LibFunc_putchar_unlocked:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     return Changed;
   case LibFunc_popen:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_pclose:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_vscanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_vsscanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_vfscanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_valloc:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_vprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_vfprintf:
   case LibFunc_vsprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_vsnprintf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 2);
     Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
   case LibFunc_open:
     // May throw; "open" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_opendir:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
case LibFunc_dunder_strndup:
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_dunder_strtok_r:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_under_IO_getc:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_under_IO_putc:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_dunder_isoc99_scanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_stat64:
   case LibFunc_lstat64:
   case LibFunc_statvfs64:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_dunder_isoc99_sscanf:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_fopen64:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_fseeko64:
   case LibFunc_ftello64:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_tmpfile64:
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
   case LibFunc_fstat64:
   case LibFunc_fstatvfs64:
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_open64:
     // May throw; "open" is a valid pthread cancellation point.
+    Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_gettimeofday:
     // Currently some platforms have the restrict keyword on the arguments to
     // gettimeofday. To be conservative, do not add noalias to gettimeofday's
     // arguments.
     Changed |= setDoesNotThrow(F);

llvm/test/CodeGen/X86/no-plt-libcalls.ll

 ;
   %fmt = getelementptr [4 x i8], [4 x i8]* @percent_s, i32 0, i32 0
   %str = getelementptr [13 x i8], [13 x i8]* @hello_world, i32 0, i32 0
   call i32 (i8*, ...) @printf(i8* %fmt, i8* %str)
   ret void
 }
 
 ; CHECK: Function Attrs: nofree nounwind nonlazybind
-; CHECK-NEXT: declare i32 @puts(i8* nocapture readonly)
+; CHECK-NEXT: declare noundef i32 @puts(i8* nocapture noundef readonly)
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 7, !"RtLibUseGOT", i32 1}

llvm/test/Transforms/InferFunctionAttrs/annotate.ll

 declare double @fabs(double)
 
 ; CHECK: declare float @fabsf(float) [[G0]]
 declare float @fabsf(float)
 
 ; CHECK: declare x86_fp80 @fabsl(x86_fp80) [[G0]]
 declare x86_fp80 @fabsl(x86_fp80)
 
-; CHECK: declare i32 @fclose(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fclose(%opaque* nocapture noundef) [[G1]]
 declare i32 @fclose(%opaque*)
 
-; CHECK: declare noalias %opaque* @fdopen(i32, i8* nocapture readonly) [[G1]]
+; CHECK: declare noalias noundef %opaque* @fdopen(i32 noundef, i8* nocapture noundef readonly) [[G1]]
 declare %opaque* @fdopen(i32, i8*)
 
-; CHECK: declare i32 @feof(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @feof(%opaque* nocapture noundef) [[G1]]
 declare i32 @feof(%opaque*)
 
-; CHECK: declare i32 @ferror(%opaque* nocapture) [[G2]]
+; CHECK: declare noundef i32 @ferror(%opaque* nocapture noundef) [[G2]]
 declare i32 @ferror(%opaque*)
 
-; CHECK: declare i32 @fflush(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fflush(%opaque* nocapture noundef) [[G1]]
 declare i32 @fflush(%opaque*)
 
 ; CHECK: declare i32 @ffs(i32) [[G0]]
 declare i32 @ffs(i32)
 
 ; CHECK: declare i32 @ffsl(i64) [[G0]]
 declare i32 @ffsl(i64)
 
 ; CHECK: declare i32 @ffsll(i64) [[G0]]
 declare i32 @ffsll(i64)
 
-; CHECK: declare i32 @fgetc(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fgetc(%opaque* nocapture noundef) [[G1]]
 declare i32 @fgetc(%opaque*)
 
-; CHECK: declare i32 @fgetpos(%opaque* nocapture, i64* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fgetpos(%opaque* nocapture noundef, i64* nocapture noundef) [[G1]]
 declare i32 @fgetpos(%opaque*, i64*)
 
-; CHECK: declare i8* @fgets(i8*, i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i8* @fgets(i8* noundef, i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i8* @fgets(i8*, i32, %opaque*)
 
-; CHECK: declare i32 @fileno(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fileno(%opaque* nocapture noundef) [[G1]]
 declare i32 @fileno(%opaque*)
 
-; CHECK: declare void @flockfile(%opaque* nocapture) [[G1]]
+; CHECK: declare void @flockfile(%opaque* nocapture noundef) [[G1]]
 declare void @flockfile(%opaque*)
 
 ; CHECK: declare double @floor(double) [[G0]]
 declare double @floor(double)
 
 ; CHECK: declare float @floorf(float) [[G0]]
 declare float @floorf(float)
 

 declare double @fmod(double, double)
 
 ; CHECK: declare float @fmodf(float, float) [[G0]]
 declare float @fmodf(float, float)
 
 ; CHECK: declare x86_fp80 @fmodl(x86_fp80, x86_fp80) [[G0]]
 declare x86_fp80 @fmodl(x86_fp80, x86_fp80)
 
-; CHECK: declare noalias %opaque* @fopen(i8* nocapture readonly, i8* nocapture readonly) [[G1]]
+; CHECK: declare noalias noundef %opaque* @fopen(i8* nocapture noundef readonly, i8* nocapture noundef readonly) [[G1]]
 declare %opaque* @fopen(i8*, i8*)
 
-; CHECK: declare i32 @fprintf(%opaque* nocapture, i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @fprintf(%opaque* nocapture noundef, i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @fprintf(%opaque*, i8*, ...)
 
-; CHECK: declare i32 @fputc(i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fputc(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @fputc(i32, %opaque*)
 
-; CHECK: declare i32 @fputs(i8* nocapture readonly, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fputs(i8* nocapture noundef readonly, %opaque* nocapture noundef) [[G1]]
 declare i32 @fputs(i8*, %opaque*)
 
-; CHECK: declare i64 @fread(i8* nocapture, i64, i64, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i64 @fread(i8* nocapture noundef, i64 noundef, i64 noundef, %opaque* nocapture noundef) [[G1]]
 declare i64 @fread(i8*, i64, i64, %opaque*)
 
 ; CHECK: declare void @free(i8* nocapture) [[G3:#[0-9]+]]
 declare void @free(i8*)
 
 ; CHECK: declare double @frexp(double, i32* nocapture) [[G1]]
 declare double @frexp(double, i32*)
 
 ; CHECK: declare float @frexpf(float, i32* nocapture) [[G1]]
 declare float @frexpf(float, i32*)
 
 ; CHECK: declare x86_fp80 @frexpl(x86_fp80, i32* nocapture) [[G1]]
 declare x86_fp80 @frexpl(x86_fp80, i32*)
 
-; CHECK: declare i32 @fscanf(%opaque* nocapture, i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @fscanf(%opaque* nocapture noundef, i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @fscanf(%opaque*, i8*, ...)
 
-; CHECK: declare i32 @fseek(%opaque* nocapture, i64, i32) [[G1]]
+; CHECK: declare noundef i32 @fseek(%opaque* nocapture noundef, i64 noundef, i32 noundef) [[G1]]
 declare i32 @fseek(%opaque*, i64, i32)
 
-; CHECK: declare i32 @fseeko(%opaque* nocapture, i64, i32) [[G1]]
+; CHECK: declare noundef i32 @fseeko(%opaque* nocapture noundef, i64 noundef, i32 noundef) [[G1]]
 declare i32 @fseeko(%opaque*, i64, i32)
 
-; CHECK-LINUX: declare i32 @fseeko64(%opaque* nocapture, i64, i32) [[G1]]
+; CHECK-LINUX: declare noundef i32 @fseeko64(%opaque* nocapture noundef, i64 noundef, i32 noundef) [[G1]]
 declare i32 @fseeko64(%opaque*, i64, i32)
 
-; CHECK: declare i32 @fsetpos(%opaque* nocapture, i64*) [[G1]]
+; CHECK: declare noundef i32 @fsetpos(%opaque* nocapture noundef, i64* noundef) [[G1]]
 declare i32 @fsetpos(%opaque*, i64*)
 
-; CHECK: declare i32 @fstat(i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fstat(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @fstat(i32, %opaque*)
 
-; CHECK-LINUX: declare i32 @fstat64(i32, %opaque* nocapture) [[G1]]
+; CHECK-LINUX: declare noundef i32 @fstat64(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @fstat64(i32, %opaque*)
 
-; CHECK: declare i32 @fstatvfs(i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @fstatvfs(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @fstatvfs(i32, %opaque*)
 
-; CHECK-LINUX: declare i32 @fstatvfs64(i32, %opaque* nocapture) [[G1]]
+; CHECK-LINUX: declare noundef i32 @fstatvfs64(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @fstatvfs64(i32, %opaque*)
 
-; CHECK: declare i64 @ftell(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i64 @ftell(%opaque* nocapture noundef) [[G1]]
 declare i64 @ftell(%opaque*)
 
-; CHECK: declare i64 @ftello(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i64 @ftello(%opaque* nocapture noundef) [[G1]]
 declare i64 @ftello(%opaque*)
 
-; CHECK-LINUX: declare i64 @ftello64(%opaque* nocapture) [[G1]]
+; CHECK-LINUX: declare noundef i64 @ftello64(%opaque* nocapture noundef) [[G1]]
 declare i64 @ftello64(%opaque*)
 
-; CHECK: declare i32 @ftrylockfile(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @ftrylockfile(%opaque* nocapture noundef) [[G1]]
 declare i32 @ftrylockfile(%opaque*)
 
-; CHECK: declare void @funlockfile(%opaque* nocapture) [[G1]]
+; CHECK: declare void @funlockfile(%opaque* nocapture noundef) [[G1]]
 declare void @funlockfile(%opaque*)
 
-; CHECK: declare i64 @fwrite(i8* nocapture, i64, i64, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i64 @fwrite(i8* nocapture noundef, i64 noundef, i64 noundef, %opaque* nocapture noundef) [[G1]]
 declare i64 @fwrite(i8*, i64, i64, %opaque*)
 
-; CHECK: declare i32 @getc(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @getc(%opaque* nocapture noundef) [[G1]]
 declare i32 @getc(%opaque*)
 
-; CHECK: declare i32 @getc_unlocked(%opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @getc_unlocked(%opaque* nocapture noundef) [[G1]]
 declare i32 @getc_unlocked(%opaque*)
 
-; CHECK: declare i32 @getchar() [[G1]]
+; CHECK: declare noundef i32 @getchar() [[G1]]
 declare i32 @getchar()
 
-; CHECK: declare i32 @getchar_unlocked() [[G1]]
+; CHECK: declare noundef i32 @getchar_unlocked() [[G1]]
 declare i32 @getchar_unlocked()
 
 ; CHECK: declare i8* @getenv(i8* nocapture) [[G2]]
 declare i8* @getenv(i8*)
 
 ; CHECK: declare i32 @getitimer(i32, %opaque* nocapture) [[G1]]
 declare i32 @getitimer(i32, %opaque*)
 
 ; CHECK: declare i32 @getlogin_r(i8* nocapture, i64) [[G1]]
 declare i32 @getlogin_r(i8*, i64)
 
 ; CHECK: declare %opaque* @getpwnam(i8* nocapture readonly) [[G1]]
 declare %opaque* @getpwnam(i8*)
 
-; CHECK: declare i8* @gets(i8*) [[G1]]
+; CHECK: declare noundef i8* @gets(i8* noundef) [[G1]]
 declare i8* @gets(i8*)
 
 ; CHECK: declare i32 @gettimeofday(%opaque* nocapture, i8* nocapture) [[G1]]
 declare i32 @gettimeofday(%opaque*, i8*)
 
 ; CHECK: declare i32 @isascii(i32) [[G0]]
 declare i32 @isascii(i32)
 

 declare double @nearbyint(double)
 
 ; CHECK: declare float @nearbyintf(float) [[G0]]
 declare float @nearbyintf(float)
 
 ; CHECK: declare x86_fp80 @nearbyintl(x86_fp80) [[G0]]
 declare x86_fp80 @nearbyintl(x86_fp80)
 
-; CHECK: declare i32 @open(i8* nocapture readonly, i32, ...) [[G0]]
+; CHECK: declare noundef i32 @open(i8* nocapture noundef readonly, i32 noundef, ...) [[G0]]
 declare i32 @open(i8*, i32, ...)
 
-; CHECK-LINUX: declare i32 @open64(i8* nocapture readonly, i32, ...) [[G0]]
+; CHECK-LINUX: declare noundef i32 @open64(i8* nocapture noundef readonly, i32 noundef, ...) [[G0]]
 declare i32 @open64(i8*, i32, ...)
 
 ; CHECK: declare noalias %opaque* @opendir(i8* nocapture readonly) [[G1]]
 declare %opaque* @opendir(i8*)
 
 ; CHECK: declare i32 @pclose(%opaque* nocapture) [[G1]]
 declare i32 @pclose(%opaque*)
 
-; CHECK: declare void @perror(i8* nocapture readonly) [[G1]]
+; CHECK: declare void @perror(i8* nocapture noundef readonly) [[G1]]
 declare void @perror(i8*)
 
 ; CHECK: declare noalias %opaque* @popen(i8* nocapture readonly, i8* nocapture readonly) [[G1]]
 declare %opaque* @popen(i8*, i8*)
 
 ; CHECK: declare i32 @posix_memalign(i8**, i64, i64) [[G0]]
 declare i32 @posix_memalign(i8**, i64, i64)
 
 ; CHECK: declare double @pow(double, double) [[G0]]
 declare double @pow(double, double)
 
 ; CHECK: declare float @powf(float, float) [[G0]]
 declare float @powf(float, float)
 
 ; CHECK: declare x86_fp80 @powl(x86_fp80, x86_fp80) [[G0]]
 declare x86_fp80 @powl(x86_fp80, x86_fp80)
 
-; CHECK: declare i64 @pread(i32, i8* nocapture, i64, i64) [[G0]]
+; CHECK: declare noundef i64 @pread(i32 noundef, i8* nocapture noundef, i64 noundef, i64 noundef) [[G0]]
 declare i64 @pread(i32, i8*, i64, i64)
 
-; CHECK: declare i32 @printf(i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @printf(i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @printf(i8*, ...)
 
-; CHECK: declare i32 @putc(i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @putc(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @putc(i32, %opaque*)
 
-; CHECK: declare i32 @putchar(i32) [[G1]]
+; CHECK: declare noundef i32 @putchar(i32 noundef) [[G1]]
 declare i32 @putchar(i32)
 
-; CHECK: declare i32 @putchar_unlocked(i32) [[G1]]
+; CHECK: declare noundef i32 @putchar_unlocked(i32 noundef) [[G1]]
 declare i32 @putchar_unlocked(i32)
 
-; CHECK: declare i32 @puts(i8* nocapture readonly) [[G1]]
+; CHECK: declare noundef i32 @puts(i8* nocapture noundef readonly) [[G1]]
 declare i32 @puts(i8*)
 
-; CHECK: declare i64 @pwrite(i32, i8* nocapture readonly, i64, i64) [[G0]]
+; CHECK: declare noundef i64 @pwrite(i32 noundef, i8* nocapture noundef readonly, i64 noundef, i64 noundef) [[G0]]
 declare i64 @pwrite(i32, i8*, i64, i64)
 
 ; CHECK: declare void @qsort(i8*, i64, i64, i32 (i8*, i8*)* nocapture) [[G0]]
 declare void @qsort(i8*, i64, i64, i32 (i8*, i8*)*)
 
-; CHECK: declare i64 @read(i32, i8* nocapture, i64) [[G0]]
+; CHECK: declare noundef i64 @read(i32 noundef, i8* nocapture noundef, i64 noundef) [[G0]]
 declare i64 @read(i32, i8*, i64)
 
 ; CHECK: declare i64 @readlink(i8* nocapture readonly, i8* nocapture, i64) [[G1]]
 declare i64 @readlink(i8*, i8*, i64)
 
 ; CHECK: declare noalias i8* @realloc(i8* nocapture, i64) [[G3]]
 declare i8* @realloc(i8*, i64)
 
 ; CHECK: declare i8* @reallocf(i8*, i64)
 declare i8* @reallocf(i8*, i64)
 
 ; CHECK: declare i8* @realpath(i8* nocapture readonly, i8*) [[G1]]
 declare i8* @realpath(i8*, i8*)
 
 ; CHECK: declare i32 @remove(i8* nocapture readonly) [[G1]]
 declare i32 @remove(i8*)
 
 ; CHECK: declare i32 @rename(i8* nocapture readonly, i8* nocapture readonly) [[G1]]
 declare i32 @rename(i8*, i8*)
 
-; CHECK: declare void @rewind(%opaque* nocapture) [[G1]]
+; CHECK: declare void @rewind(%opaque* nocapture noundef) [[G1]]
 declare void @rewind(%opaque*)
 
 ; CHECK: declare double @rint(double) [[G0]]
 declare double @rint(double)
 
 ; CHECK: declare float @rintf(float) [[G0]]
 declare float @rintf(float)
 
 ; CHECK: declare x86_fp80 @rintl(x86_fp80) [[G0]]
 declare x86_fp80 @rintl(x86_fp80)
 
 ; CHECK: declare i32 @rmdir(i8* nocapture readonly) [[G1]]
 declare i32 @rmdir(i8*)
 
 ; CHECK: declare double @round(double) [[G0]]
 declare double @round(double)
 
 ; CHECK: declare float @roundf(float) [[G0]]
 declare float @roundf(float)
 
 ; CHECK: declare x86_fp80 @roundl(x86_fp80) [[G0]]
 declare x86_fp80 @roundl(x86_fp80)
 
-; CHECK: declare i32 @scanf(i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @scanf(i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @scanf(i8*, ...)
 
 ; CHECK: declare void @setbuf(%opaque* nocapture, i8*) [[G1]]
 declare void @setbuf(%opaque*, i8*)
 
 ; CHECK: declare i32 @setitimer(i32, %opaque* nocapture readonly, %opaque* nocapture) [[G1]]
 declare i32 @setitimer(i32, %opaque*, %opaque*)
 

 declare float @sinhf(float)
 
 ; CHECK: declare x86_fp80 @sinhl(x86_fp80) [[G0]]
 declare x86_fp80 @sinhl(x86_fp80)
 
 ; CHECK: declare x86_fp80 @sinl(x86_fp80) [[G0]]
 declare x86_fp80 @sinl(x86_fp80)
 
-; CHECK: declare i32 @snprintf(i8* noalias nocapture, i64, i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @snprintf(i8* noalias nocapture noundef, i64 noundef, i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @snprintf(i8*, i64, i8*, ...)
 
-; CHECK: declare i32 @sprintf(i8* noalias nocapture, i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @sprintf(i8* noalias nocapture noundef, i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @sprintf(i8*, i8*, ...)
 
 ; CHECK: declare double @sqrt(double) [[G0]]
 declare double @sqrt(double)
 
 ; CHECK: declare float @sqrtf(float) [[G0]]
 declare float @sqrtf(float)
 
 ; CHECK: declare x86_fp80 @sqrtl(x86_fp80) [[G0]]
 declare x86_fp80 @sqrtl(x86_fp80)
 
-; CHECK: declare i32 @sscanf(i8* nocapture readonly, i8* nocapture readonly, ...) [[G1]]
+; CHECK: declare noundef i32 @sscanf(i8* nocapture noundef readonly, i8* nocapture noundef readonly, ...) [[G1]]
 declare i32 @sscanf(i8*, i8*, ...)
 
 ; CHECK: declare i32 @stat(i8* nocapture readonly, %opaque* nocapture) [[G1]]
 declare i32 @stat(i8*, %opaque*)
 
 ; CHECK-LINUX: declare i32 @stat64(i8* nocapture readonly, %opaque* nocapture) [[G1]]
 declare i32 @stat64(i8*, %opaque*)
 

 declare float @truncf(float)
 
 ; CHECK: declare x86_fp80 @truncl(x86_fp80) [[G0]]
 declare x86_fp80 @truncl(x86_fp80)
 
 ; CHECK: declare i32 @uname(%opaque* nocapture) [[G1]]
 declare i32 @uname(%opaque*)
 
-; CHECK: declare i32 @ungetc(i32, %opaque* nocapture) [[G1]]
+; CHECK: declare noundef i32 @ungetc(i32 noundef, %opaque* nocapture noundef) [[G1]]
 declare i32 @ungetc(i32, %opaque*)
 
 ; CHECK: declare i32 @unlink(i8* nocapture readonly) [[G1]]
 declare i32 @unlink(i8*)
 
 ; CHECK: declare i32 @unsetenv(i8* nocapture readonly) [[G1]]
 declare i32 @unsetenv(i8*)
 
 ; CHECK: declare i32 @utime(i8* nocapture readonly, %opaque* nocapture readonly) [[G1]]
 declare i32 @utime(i8*, %opaque*)
 
 ; CHECK: declare i32 @utimes(i8* nocapture readonly, %opaque* nocapture readonly) [[G1]]
 declare i32 @utimes(i8*, %opaque*)
 
 ; CHECK: declare noalias i8* @valloc(i64) [[G1]]
 declare i8* @valloc(i64)
 
-; CHECK: declare i32 @vfprintf(%opaque* nocapture, i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vfprintf(%opaque* nocapture noundef, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vfprintf(%opaque*, i8*, %opaque*)
 
-; CHECK: declare i32 @vfscanf(%opaque* nocapture, i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vfscanf(%opaque* nocapture noundef, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vfscanf(%opaque*, i8*, %opaque*)
 
-; CHECK: declare i32 @vprintf(i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vprintf(i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vprintf(i8*, %opaque*)
 
-; CHECK: declare i32 @vscanf(i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vscanf(i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vscanf(i8*, %opaque*)
 
-; CHECK: declare i32 @vsnprintf(i8* nocapture, i64, i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vsnprintf(i8* nocapture noundef, i64 noundef, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vsnprintf(i8*, i64, i8*, %opaque*)
 
-; CHECK: declare i32 @vsprintf(i8* nocapture, i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vsprintf(i8* nocapture noundef, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vsprintf(i8*, i8*, %opaque*)
 
-; CHECK: declare i32 @vsscanf(i8* nocapture readonly, i8* nocapture readonly, %opaque*) [[G1]]
+; CHECK: declare noundef i32 @vsscanf(i8* nocapture noundef readonly, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]
 declare i32 @vsscanf(i8*, i8*, %opaque*)
 
-; CHECK: declare i64 @write(i32, i8* nocapture readonly, i64) [[G0]]
+; CHECK: declare noundef i64 @write(i32 noundef, i8* nocapture noundef readonly, i64 noundef) [[G0]]
 declare i64 @write(i32, i8*, i64)
 
 
 ; memset_pattern16 isn't available everywhere.
 ; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture, i8* nocapture readonly, i64) [[G5:#[0-9]+]]
 declare void @memset_pattern16(i8*, i8*, i64)
 
 ; CHECK: attributes [[G0]] = { nofree }
 ; CHECK: attributes [[G1]] = { nofree nounwind }
 ; CHECK: attributes [[G2]] = { nofree nounwind readonly }
 ; CHECK: attributes [[G3]] = { nounwind }
 ; CHECK: attributes [[G4]] = { argmemonly nofree nounwind readonly }
 ; CHECK-DARWIN: attributes [[G5]] = { argmemonly nofree }