[clang] Fix -fp-model={strict|precise} to disable -fapprox-func

[kawashima-fj]

Summary

-fapprox-func should be disabled by -fp-model={strict|precise}, as well as other fast-math flags. See the last changes in clang/test/Driver/fp-model.c.

Probably this route (case options::OPT_ffp_model_EQ) was forgot to update in D106191 and D114564. There is no appropriate reason not to disable the flag.

This commit also updates other regression tests, which are not directly related to this bug, for consistency with other fast-math flags.

[kawashima-fj]

I found some errors in Clang Compiler User’s Manual. I will update of the Manual in another patch.

[masoud.ataei]

LGTM

[zahiraam]

clang/test/Driver/fp-model.c

180

Shouldn't be worth adding a rule for -ffast-math and ffp-model=fast (even if it seems redundant)?

[kawashima-fj]

Update a test to include the ffast-math -ffp-model=fast pattern.

[kawashima-fj]

clang/test/Driver/fp-model.c

180

-ffast-math -ffp-model=fast is added at line 134.

[zahiraam]

In D138109#3932691, @kawashima-fj wrote:

Update a test to include the ffast-math -ffp-model=fast pattern.

Thanks. Looks good to me.

clang/lib/Driver/ToolChains/Clang.cpp

for (const Arg *A : Args) {
     bool PreciseFPModel = false;
     switch (optID) {
     default:
       break;
     case options::OPT_ffp_model_EQ: {
       // If -ffp-model= is seen, reset to fno-fast-math
       HonorINFs = true;
       HonorNaNs = true;
+      ApproxFunc = false;
       // Turning *off* -ffast-math restores the toolchain default.
       MathErrno = TC.IsMathErrnoDefault();
       AssociativeMath = false;
       ReciprocalMath = false;
       SignedZeros = true;
       // -fno_fast_math restores default denormal and fpcontract handling
       FPContract = "on";
       DenormalFPMath = llvm::DenormalMode::getIEEE();

clang/test/CodeGen/fp-options-to-fast-math-flags.c

 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck -check-prefix CHECK-PRECISE %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -menable-no-nans -emit-llvm -o - %s | FileCheck -check-prefix CHECK-NO-NANS %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -menable-no-infs -emit-llvm -o - %s | FileCheck -check-prefix CHECK-NO-INFS %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -ffinite-math-only -emit-llvm -o - %s | FileCheck -check-prefix CHECK-FINITE %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fno-signed-zeros -emit-llvm -o - %s | FileCheck -check-prefix CHECK-NO-SIGNED-ZEROS %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -mreassociate -emit-llvm -o - %s | FileCheck -check-prefix CHECK-REASSOC %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -freciprocal-math -emit-llvm -o - %s | FileCheck -check-prefix CHECK-RECIP %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fapprox-func -emit-llvm -o - %s | FileCheck -check-prefix CHECK-AFN %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -funsafe-math-optimizations -emit-llvm -o - %s | FileCheck -check-prefix CHECK-UNSAFE %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -ffast-math -emit-llvm -o - %s | FileCheck -check-prefix CHECK-FAST %s
 
 float fn(float);
 
 float test(float a) {
   return a + fn(a);
 }

 // CHECK-NO-SIGNED-ZEROS: {{%.+}} = fadd nsz float {{%.+}}, [[CALL_RES]]
 
 // CHECK-REASSOC: [[CALL_RES:%.+]] = call reassoc float @fn(float noundef {{%.+}})
 // CHECK-REASSOC: {{%.+}} = fadd reassoc float {{%.+}}, [[CALL_RES]]
 
 // CHECK-RECIP: [[CALL_RES:%.+]] = call arcp float @fn(float noundef {{%.+}})
 // CHECK-RECIP: {{%.+}} = fadd arcp float {{%.+}}, [[CALL_RES]]
 
+// CHECK-AFN: [[CALL_RES:%.+]] = call afn float @fn(float noundef {{%.+}})
+// CHECK-AFN: {{%.+}} = fadd afn float {{%.+}}, [[CALL_RES]]
+
 // CHECK-UNSAFE: [[CALL_RES:%.+]] = call reassoc nsz arcp afn float @fn(float noundef {{%.+}})
 // CHECK-UNSAFE: {{%.+}} = fadd reassoc nsz arcp afn float {{%.+}}, [[CALL_RES]]
 
 // CHECK-FAST: [[CALL_RES:%.+]] = call reassoc nnan ninf nsz arcp afn float @fn(float noundef {{%.+}})
 // CHECK-FAST: {{%.+}} = fadd reassoc nnan ninf nsz arcp afn float {{%.+}}, [[CALL_RES]]

clang/test/Driver/fast-math.c

 // CHECK-NO-APPROX-FUNC-FAST-MATH: "-cc1"
 // CHECK-NO-APPROX-FUNC-FAST-MATH: "-ffast-math"
 //
 // RUN: %clang -### -fapprox-func -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-APPROX-FUNC %s
 // CHECK-APPROX-FUNC: "-cc1"
 // CHECK-APPROX-FUNC: "-fapprox-func"
 //
+// RUN: %clang -### -fno-fast-math -fapprox-func -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-NO-FAST-MATH-APPROX-FUNC %s
+// CHECK-NO-FAST-MATH-APPROX-FUNC: "-cc1"
+// CHECK-NO-FAST-MATH-APPROX-FUNC: "-fapprox-func"
+//
+// RUN: %clang -### -fapprox-func -fno-fast-math -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-APPROX-FUNC-NO-FAST-MATH %s
+// CHECK-APPROX-FUNC-NO-FAST-MATH: "-cc1"
+// CHECK-APPROX-FUNC-NO-FAST-MATH-NOT: "-fapprox-func"
+//
 // RUN: %clang -### -fmath-errno -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MATH-ERRNO %s
 // CHECK-MATH-ERRNO: "-cc1"
 // CHECK-MATH-ERRNO: "-fmath-errno"
 //
 // RUN: %clang -### -fmath-errno -fno-math-errno -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NO-MATH-ERRNO %s
 // CHECK-NO-MATH-ERRNO: "-cc1"

clang/test/Driver/fp-model.c

 // WARN11-NOT: warning: overriding '-ffp-model=strict' option with '-ffp-model=strict' [-Woverriding-t-option]
 
 // RUN: %clang -### -Ofast -ffp-model=strict -c %s 2>&1 | FileCheck \
 // RUN:   --check-prefix=WARN12 %s
 // RUN: %clang -### -ffast-math -ffp-model=strict -c %s 2>&1 | FileCheck \
 // RUN:   --check-prefix=WARN12 %s
 // WARN12-NOT: warning: overriding '-ffp-model=strict' option with '-ffp-model=strict' [-Woverriding-t-option]
 
+// RUN: %clang -### -ffp-model=strict -fapprox-func -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=WARN13 %s
+// WARN13: warning: overriding '-ffp-model=strict' option with '-fapprox-func' [-Woverriding-t-option]
+
 // RUN: %clang -### -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOROUND %s
 // CHECK-NOROUND: "-cc1"
 // CHECK-NOROUND: "-fno-rounding-math"
 
 // RUN: %clang -### -frounding-math -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-ROUND --implicit-check-not ffp-exception-behavior=strict %s
 // CHECK-ROUND: "-cc1"
 // CHECK-ROUND: "-frounding-math"
 
 // RUN: %clang -### -ftrapping-math -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-TRAP %s
 // CHECK-TRAP: "-cc1"
 // CHECK-TRAP: "-ffp-exception-behavior=strict"
 
 // RUN: %clang -### -nostdinc -ffp-model=fast -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-FPM-FAST %s
 // CHECK-FPM-FAST: "-cc1"
 // CHECK-FPM-FAST: "-menable-no-infs"
 // CHECK-FPM-FAST: "-menable-no-nans"
+// CHECK-FPM-FAST: "-fapprox-func"
 // CHECK-FPM-FAST: "-funsafe-math-optimizations"
 // CHECK-FPM-FAST: "-fno-signed-zeros"
 // CHECK-FPM-FAST: "-mreassociate"
 // CHECK-FPM-FAST: "-freciprocal-math"
 // CHECK-FPM-FAST: "-ffp-contract=fast"
 // CHECK-FPM-FAST: "-fno-rounding-math"
 // CHECK-FPM-FAST: "-ffast-math"
 // CHECK-FPM-FAST: "-ffinite-math-only"

 // CHECK-FEB-MAYTRAP: "-ffp-exception-behavior=maytrap"
 
 // RUN: %clang -### -nostdinc -ffp-exception-behavior=ignore -c %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-FEB-IGNORE %s
 // CHECK-FEB-IGNORE: "-cc1"
 // CHECK-FEB-IGNORE: "-fno-rounding-math"
 // CHECK-FEB-IGNORE: "-ffp-exception-behavior=ignore"
 
+// RUN: %clang -### -nostdinc -ffast-math -ffp-model=fast -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-FASTMATH-FPM-FAST %s
+// CHECK-FASTMATH-FPM-FAST: "-cc1"
+// CHECK-FASTMATH-FPM-FAST: "-menable-no-infs"
+// CHECK-FASTMATH-FPM-FAST: "-menable-no-nans"
+// CHECK-FASTMATH-FPM-FAST: "-fapprox-func"
+// CHECK-FASTMATH-FPM-FAST: "-funsafe-math-optimizations"
+// CHECK-FASTMATH-FPM-FAST: "-fno-signed-zeros"
+// CHECK-FASTMATH-FPM-FAST: "-mreassociate"
+// CHECK-FASTMATH-FPM-FAST: "-freciprocal-math"
+// CHECK-FASTMATH-FPM-FAST: "-ffp-contract=fast"
+// CHECK-FASTMATH-FPM-FAST: "-fno-rounding-math"
+// CHECK-FASTMATH-FPM-FAST: "-ffast-math"
+// CHECK-FASTMATH-FPM-FAST: "-ffinite-math-only"
+
+// RUN: %clang -### -nostdinc -ffast-math -ffp-model=precise -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-FASTMATH-FPM-PRECISE %s
+// CHECK-FASTMATH-FPM-PRECISE:     "-cc1"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-menable-no-infs"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-menable-no-nans"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-fapprox-func"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-funsafe-math-optimizations"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-fno-signed-zeros"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-mreassociate"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-freciprocal-math"
+// CHECK-FASTMATH-FPM-PRECISE:     "-ffp-contract=on"
+// CHECK-FASTMATH-FPM-PRECISE:     "-fno-rounding-math"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-ffast-math"
+// CHECK-FASTMATH-FPM-PRECISE-NOT: "-ffinite-math-only"
+
+// RUN: %clang -### -nostdinc -ffast-math -ffp-model=strict -c %s 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-FASTMATH-FPM-STRICT %s
+// CHECK-FASTMATH-FPM-STRICT:     "-cc1"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-menable-no-infs"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-menable-no-nans"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-fapprox-func"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-funsafe-math-optimizations"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-fno-signed-zeros"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-mreassociate"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-freciprocal-math"
+// CHECK-FASTMATH-FPM-STRICT:     "-ffp-contract=off"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-fno-rounding-math"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-ffast-math"
+// CHECK-FASTMATH-FPM-STRICT-NOT: "-ffinite-math-only"