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[clang] Lower modf builtin using llvm.modf intrinsic #126750

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Feb 19, 2025
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[clang] Lower modf builtin using llvm.modf intrinsic #126750

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eee5bc8
[clang] Lower modf builtin using `llvm.modf` intrinsic
MacDue Feb 11, 2025
0121d99
Fixups
MacDue Feb 11, 2025
0c5a3a6
Fixups
MacDue Feb 12, 2025
7b1f5cc
Don't use intrinsic in constrained mode
MacDue Feb 17, 2025
6fa8a5b
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MacDue Feb 17, 2025
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25 changes: 25 additions & 0 deletions clang/lib/CodeGen/CGBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -859,6 +859,24 @@ static void emitSincosBuiltin(CodeGenFunction &CGF, const CallExpr *E,
StoreCos->setMetadata(LLVMContext::MD_noalias, AliasScopeList);
}

static llvm::Value *emitModfBuiltin(CodeGenFunction &CGF, const CallExpr *E,
llvm::Intrinsic::ID IntrinsicID) {
llvm::Value *Val = CGF.EmitScalarExpr(E->getArg(0));
llvm::Value *IntPartDest = CGF.EmitScalarExpr(E->getArg(1));

llvm::Value *Call =
CGF.Builder.CreateIntrinsic(IntrinsicID, {Val->getType()}, Val);

llvm::Value *FractionalResult = CGF.Builder.CreateExtractValue(Call, 0);
llvm::Value *IntegralResult = CGF.Builder.CreateExtractValue(Call, 1);

QualType DestPtrType = E->getArg(1)->getType()->getPointeeType();
LValue IntegralLV = CGF.MakeNaturalAlignAddrLValue(IntPartDest, DestPtrType);
CGF.EmitStoreOfScalar(IntegralResult, IntegralLV);

return FractionalResult;
}

/// EmitFAbs - Emit a call to @llvm.fabs().
static Value *EmitFAbs(CodeGenFunction &CGF, Value *V) {
Function *F = CGF.CGM.getIntrinsic(Intrinsic::fabs, V->getType());
Expand Down Expand Up @@ -4096,6 +4114,13 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
case Builtin::BI__builtin_frexpf128:
case Builtin::BI__builtin_frexpf16:
return RValue::get(emitFrexpBuiltin(*this, E, Intrinsic::frexp));
case Builtin::BImodf:
case Builtin::BImodff:
case Builtin::BImodfl:
case Builtin::BI__builtin_modf:
case Builtin::BI__builtin_modff:
case Builtin::BI__builtin_modfl:
return RValue::get(emitModfBuiltin(*this, E, Intrinsic::modf));
case Builtin::BI__builtin_isgreater:
case Builtin::BI__builtin_isgreaterequal:
case Builtin::BI__builtin_isless:
Expand Down
32 changes: 25 additions & 7 deletions clang/test/CodeGen/X86/math-builtins.c
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Expand Up @@ -38,6 +38,24 @@ void foo(double *d, float f, float *fp, long double *l, int *i, const char *c) {
// NO__ERRNO-NEXT: [[FREXP_F128_0:%.+]] = extractvalue { fp128, i32 } [[FREXP_F128]], 0


// NO__ERRNO: [[MODF_F64:%.+]] = call { double, double } @llvm.modf.f64(double %{{.+}})
// NO__ERRNO-NEXT: [[MODF_F64_FP:%.+]] = extractvalue { double, double } [[MODF_F64]], 0
// NO__ERRNO-NEXT: [[MODF_F64_IP:%.+]] = extractvalue { double, double } [[MODF_F64]], 1
// NO__ERRNO-NEXT: store double [[MODF_F64_IP]], ptr %{{.+}}, align 8

// NO__ERRNO: [[MODF_F32:%.+]] = call { float, float } @llvm.modf.f32(float %{{.+}})
// NO__ERRNO-NEXT: [[MODF_F32_FP:%.+]] = extractvalue { float, float } [[MODF_F32]], 0
// NO__ERRNO-NEXT: [[MODF_F32_IP:%.+]] = extractvalue { float, float } [[MODF_F32]], 1
// NO__ERRNO-NEXT: store float [[MODF_F32_IP]], ptr %{{.+}}, align 4

// NO__ERRNO: [[MODF_F80:%.+]] = call { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80 %{{.+}})
// NO__ERRNO-NEXT: [[MODF_F80_FP:%.+]] = extractvalue { x86_fp80, x86_fp80 } [[MODF_F80]], 0
// NO__ERRNO-NEXT: [[MODF_F80_IP:%.+]] = extractvalue { x86_fp80, x86_fp80 } [[MODF_F80]], 1
// NO__ERRNO-NEXT: store x86_fp80 [[MODF_F80_IP]], ptr %{{.+}}, align 16

// NO__ERRNO: call fp128 @modff128(fp128 noundef %{{.+}}, ptr noundef %{{.+}})


// NO__ERRNO: [[SINCOS_F64:%.+]] = call { double, double } @llvm.sincos.f64(double %{{.+}})
// NO__ERRNO-NEXT: [[SINCOS_F64_0:%.+]] = extractvalue { double, double } [[SINCOS_F64]], 0
// NO__ERRNO-NEXT: [[SINCOS_F64_1:%.+]] = extractvalue { double, double } [[SINCOS_F64]], 1
Expand Down Expand Up @@ -139,13 +157,13 @@ void foo(double *d, float f, float *fp, long double *l, int *i, const char *c) {

__builtin_modf(f,d); __builtin_modff(f,fp); __builtin_modfl(f,l); __builtin_modff128(f,l);

// NO__ERRNO: declare double @modf(double noundef, ptr noundef) [[NOT_READNONE:#[0-9]+]]
// NO__ERRNO: declare float @modff(float noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare x86_fp80 @modfl(x86_fp80 noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare fp128 @modff128(fp128 noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare double @modf(double noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare float @modff(float noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare x86_fp80 @modfl(x86_fp80 noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare { double, double } @llvm.modf.f64(double) [[READNONE_INTRINSIC]]
// NO__ERRNO: declare { float, float } @llvm.modf.f32(float) [[READNONE_INTRINSIC]]
// NO__ERRNO: declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80) [[READNONE_INTRINSIC]]
// NO__ERRNO: declare fp128 @modff128(fp128 noundef, ptr noundef) [[NOT_READNONE:#[0-9]+]]
// HAS_ERRNO: declare { double, double } @llvm.modf.f64(double) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare { float, float } @llvm.modf.f32(float) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare fp128 @modff128(fp128 noundef, ptr noundef) [[NOT_READNONE]]

__builtin_nan(c); __builtin_nanf(c); __builtin_nanl(c); __builtin_nanf128(c);
Expand Down
2 changes: 1 addition & 1 deletion clang/test/CodeGen/aix-builtin-mapping.c
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Expand Up @@ -17,6 +17,6 @@ int main()
returnValue = __builtin_ldexpl(1.0L, 1);
}

// CHECK: %call = call double @modf(double noundef 1.000000e+00, ptr noundef %DummyLongDouble) #3
// CHECK: %{{.+}} = call { double, double } @llvm.modf.f64(double 1.000000e+00)
// CHECK: %{{.+}} = call { double, i32 } @llvm.frexp.f64.i32(double 0.000000e+00)
// CHECK: %{{.+}} = call double @llvm.ldexp.f64.i32(double 1.000000e+00, i32 1)
11 changes: 8 additions & 3 deletions clang/test/CodeGen/builtin-attributes.c
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Expand Up @@ -24,6 +24,11 @@ char* f2(char* a, char* b) {
return __builtin_strstr(a, b);
}

// Note: Use asm label to disable intrinsic lowering of modf.
double modf(double x, double*) asm("modf");
float modff(float x, float*) asm("modff");
long double modfl(long double x, long double*) asm("modfl");

// frexp is NOT readnone. It writes to its pointer argument.
//
// CHECK: f3
Expand Down Expand Up @@ -55,9 +60,9 @@ int f3(double x) {
frexp(x, &e);
frexpf(x, &e);
frexpl(x, &e);
__builtin_modf(x, &e);
__builtin_modff(x, &e);
__builtin_modfl(x, &e);
modf(x, &e);
modff(x, &e);
modfl(x, &e);
__builtin_remquo(x, x, &e);
__builtin_remquof(x, x, &e);
__builtin_remquol(x, x, &e);
Expand Down
6 changes: 3 additions & 3 deletions clang/test/CodeGen/math-builtins-long.c
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Expand Up @@ -58,9 +58,9 @@ void foo(long double f, long double *l, int *i, const char *c) {
// PPCF128: call fp128 @ldexpf128(fp128 noundef %{{.+}}, {{(signext)?.+}})
__builtin_ldexpl(f,f);

// F80: call x86_fp80 @modfl(x86_fp80 noundef %{{.+}}, ptr noundef %{{.+}})
// PPC: call ppc_fp128 @modfl(ppc_fp128 noundef %{{.+}}, ptr noundef %{{.+}})
// X86F128: call fp128 @modfl(fp128 noundef %{{.+}}, ptr noundef %{{.+}})
// F80: call { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80 %{{.+}})
// PPC: call { ppc_fp128, ppc_fp128 } @llvm.modf.ppcf128(ppc_fp128 %{{.+}})
// X86F128: call { fp128, fp128 } @llvm.modf.f128(fp128 %{{.+}})
// PPCF128: call fp128 @modff128(fp128 noundef %{{.+}}, ptr noundef %{{.+}})
__builtin_modfl(f,l);

Expand Down
18 changes: 9 additions & 9 deletions clang/test/CodeGen/math-libcalls.c
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Expand Up @@ -83,15 +83,15 @@ void foo(double *d, float f, float *fp, long double *l, int *i, const char *c) {

modf(f,d); modff(f,fp); modfl(f,l);

// NO__ERRNO: declare double @modf(double noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare float @modff(float noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare x86_fp80 @modfl(x86_fp80 noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare double @modf(double noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare float @modff(float noundef, ptr noundef) [[NOT_READNONE]]
// HAS_ERRNO: declare x86_fp80 @modfl(x86_fp80 noundef, ptr noundef) [[NOT_READNONE]]
// HAS_MAYTRAP: declare double @modf(double noundef, ptr noundef) [[NOT_READNONE]]
// HAS_MAYTRAP: declare float @modff(float noundef, ptr noundef) [[NOT_READNONE]]
// HAS_MAYTRAP: declare x86_fp80 @modfl(x86_fp80 noundef, ptr noundef) [[NOT_READNONE]]
// NO__ERRNO: declare { double, double } @llvm.modf.f64(double) [[READNONE_INTRINSIC]]
// NO__ERRNO: declare { float, float } @llvm.modf.f32(float) [[READNONE_INTRINSIC]]
// NO__ERRNO: declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare { double, double } @llvm.modf.f64(double) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare { float, float } @llvm.modf.f32(float) [[READNONE_INTRINSIC]]
// HAS_ERRNO: declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80) [[READNONE_INTRINSIC]]
// HAS_MAYTRAP: declare { double, double } @llvm.modf.f64(double) [[READNONE_INTRINSIC]]
// HAS_MAYTRAP: declare { float, float } @llvm.modf.f32(float) [[READNONE_INTRINSIC]]
// HAS_MAYTRAP: declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80) [[READNONE_INTRINSIC]]

nan(c); nanf(c); nanl(c);

Expand Down