[clang] Reland "[clang] Lower modf builtin using `llvm.modf` intrinsic" (PR #130761)
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cfe-commits at lists.llvm.org
Tue Mar 11 05:14:06 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-x86
Author: Benjamin Maxwell (MacDue)
<details>
<summary>Changes</summary>
Reverts https://github.com/llvm/llvm-project/commit/c40f0fe4348bb9304b95bd317665bf1cb2bdcc85
Original description:
This updates the existing modf[f|l] builtin to be lowered via the llvm.modf.* intrinsic (rather than directly to a library call).
The Windows 32-bit x86 missing `modff` symbol issue should have been solved in: https://github.com/llvm/llvm-project/pull/130636.
---
Full diff: https://github.com/llvm/llvm-project/pull/130761.diff
6 Files Affected:
- (modified) clang/lib/CodeGen/CGBuiltin.cpp (+27)
- (modified) clang/test/CodeGen/X86/math-builtins.c (+25-7)
- (modified) clang/test/CodeGen/aix-builtin-mapping.c (+1-1)
- (modified) clang/test/CodeGen/builtin-attributes.c (+8-3)
- (modified) clang/test/CodeGen/math-builtins-long.c (+3-3)
- (modified) clang/test/CodeGen/math-libcalls.c (+6-6)
``````````diff
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 167bd6e4695c1..ba78de049ce96 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -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());
@@ -4120,6 +4138,15 @@ 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:
+ if (Builder.getIsFPConstrained())
+ break; // TODO: Emit constrained modf intrinsic once one exists.
+ return RValue::get(emitModfBuiltin(*this, E, Intrinsic::modf));
case Builtin::BI__builtin_isgreater:
case Builtin::BI__builtin_isgreaterequal:
case Builtin::BI__builtin_isless:
diff --git a/clang/test/CodeGen/X86/math-builtins.c b/clang/test/CodeGen/X86/math-builtins.c
index 481d3c043683e..8a85d1f6c3a76 100644
--- a/clang/test/CodeGen/X86/math-builtins.c
+++ b/clang/test/CodeGen/X86/math-builtins.c
@@ -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
@@ -158,13 +176,13 @@ 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);
diff --git a/clang/test/CodeGen/aix-builtin-mapping.c b/clang/test/CodeGen/aix-builtin-mapping.c
index a79218c6f1d8b..cc1cc1a44f32c 100644
--- a/clang/test/CodeGen/aix-builtin-mapping.c
+++ b/clang/test/CodeGen/aix-builtin-mapping.c
@@ -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)
diff --git a/clang/test/CodeGen/builtin-attributes.c b/clang/test/CodeGen/builtin-attributes.c
index e5b0faccfd23f..506b165fcf36e 100644
--- a/clang/test/CodeGen/builtin-attributes.c
+++ b/clang/test/CodeGen/builtin-attributes.c
@@ -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
@@ -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);
diff --git a/clang/test/CodeGen/math-builtins-long.c b/clang/test/CodeGen/math-builtins-long.c
index 183349e0f0173..87e64a2eaa1c3 100644
--- a/clang/test/CodeGen/math-builtins-long.c
+++ b/clang/test/CodeGen/math-builtins-long.c
@@ -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);
diff --git a/clang/test/CodeGen/math-libcalls.c b/clang/test/CodeGen/math-libcalls.c
index 14fdee77f4d78..ad297828f48ed 100644
--- a/clang/test/CodeGen/math-libcalls.c
+++ b/clang/test/CodeGen/math-libcalls.c
@@ -83,12 +83,12 @@ 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]]
+ // 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 @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]]
``````````
</details>
https://github.com/llvm/llvm-project/pull/130761
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