zahiraam updated this revision to Diff 545666.
zahiraam marked an inline comment as done.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D151834/new/
https://reviews.llvm.org/D151834
Files:
clang/docs/LanguageExtensions.rst
clang/docs/UsersManual.rst
clang/include/clang/Basic/FPOptions.def
clang/include/clang/Basic/LangOptions.h
clang/lib/CodeGen/CGBuiltin.cpp
clang/lib/CodeGen/CGCall.cpp
clang/lib/CodeGen/CodeGenModule.h
clang/test/CodeGen/math-errno.c
Index: clang/test/CodeGen/math-errno.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/math-errno.c
@@ -0,0 +1,64 @@
+// -O2
+// RUN: %clang_cc1 -Wno-implicit-function-declaration \
+// RUN: -fmath-errno -ffp-contract=on -fno-rounding-math -O2 -emit-llvm -o - %s \
+// RUN: | FileCheck %s
+
+// -ffast-math
+// RUN: %clang_cc1 -Wno-implicit-function-declaration \
+// RUN: -menable-no-infs -menable-no-nans -fapprox-func \
+// RUN: -funsafe-math-optimizations -fno-signed-zeros -mreassociate \
+// RUN: -freciprocal-math -ffp-contract=fast -fno-rounding-math -ffast-math \
+// RUN: -ffinite-math-only -ffast-math -emit-llvm -o - %s \
+// RUN: | FileCheck %s -check-prefix=FAST
+
+// -O0
+// RUN: %clang_cc1 -Wno-implicit-function-declaration \
+// RUN: -fmath-errno -ffp-contract=on -fno-rounding-math -O0 \
+// RUN: -emit-llvm -o - %s | FileCheck %s -check-prefix=NOOPT
+
+#pragma float_control(precise,on)
+float f1(float x) {
+ return sqrtf(x);
+}
+
+// CHECK-LABEL: define dso_local float @f1
+// CHECK: tail call float @sqrtf(float noundef {{.*}}) #[[ATTR4_O2:[0-9]+]]
+
+// FAST-LABEL: define dso_local nofpclass(nan inf) float @f1
+// FAST: call fast nofpclass(nan inf) float @sqrtf(float noundef nofpclass(nan inf) {{.*}}) #[[ATTR3_FAST:[0-9]+]]
+
+// NOOPT-LABEL: define dso_local float @f1
+// NOOPT: call float @sqrtf(float noundef {{.*}}) #[[ATTR4_NOOPT:[0-9]+]]
+
+#pragma float_control(precise,off)
+float f2(float x) {
+ return sqrtf(x);
+}
+
+// CHECK-LABEL: define dso_local float @f2
+// CHECK: tail call float @llvm.sqrt.f32(float {{.*}})
+
+// FAST-LABEL: define dso_local nofpclass(nan inf) float @f2
+// FAST: call fast float @llvm.sqrt.f32(float {{.*}})
+
+// NOOPT-LABEL: define dso_local float @f2
+// NOOPT: call float @sqrtf(float {{.*}}) #[[ATTR4_NOOPT:[0-9]+]]
+
+__attribute__((optnone))
+float f3(float x) {
+ x = sqrtf(x);
+ return x;
+}
+
+// CHECK-LABEL: define dso_local float @f3
+// CHECK: call float @sqrtf(float noundef {{.*}})
+
+// FAST-LABEL: define dso_local nofpclass(nan inf) float @f3
+// FAST: call fast nofpclass(nan inf) float @sqrtf(float noundef nofpclass(nan inf) {{.*}}) #[[ATTR4_FAST:[0-9]+]]
+
+// NOOPT-LABEL: define dso_local float @f3
+// NOOPT: call float @sqrtf(float noundef %0) #[[ATTR4_NOOPT:[0-9]+]]
+
+// CHECK: [[ATTR4_O2]] = { nounwind }
+// FAST: [[ATTR3_FAST]] = { nounwind willreturn memory(none) }
+// NOOPT: [[ATTR4_NOOPT]] = { nounwind }
Index: clang/lib/CodeGen/CodeGenModule.h
===================================================================
--- clang/lib/CodeGen/CodeGenModule.h
+++ clang/lib/CodeGen/CodeGenModule.h
@@ -1252,6 +1252,12 @@
llvm::AttributeList &Attrs, unsigned &CallingConv,
bool AttrOnCallSite, bool IsThunk);
+ /// Adjust Memory attribute to ensure that the BE gets the right attribute
+ // in order to generate the library call or the intrinsic for the function
+ // name 'Name'.
+ void AdjustMemoryAttribute(StringRef Name, CGCalleeInfo CalleeInfo,
+ llvm::AttributeList &Attrs);
+
/// Adds attributes to F according to our CodeGenOptions and LangOptions, as
/// though we had emitted it ourselves. We remove any attributes on F that
/// conflict with the attributes we add here.
Index: clang/lib/CodeGen/CGCall.cpp
===================================================================
--- clang/lib/CodeGen/CGCall.cpp
+++ clang/lib/CodeGen/CGCall.cpp
@@ -2247,6 +2247,17 @@
return Mask;
}
+void CodeGenModule::AdjustMemoryAttribute(StringRef Name,
+ CGCalleeInfo CalleeInfo,
+ llvm::AttributeList &Attrs) {
+ if (Attrs.getMemoryEffects().getModRef() == llvm::ModRefInfo::NoModRef) {
+ Attrs = Attrs.removeFnAttribute(getLLVMContext(), llvm::Attribute::Memory);
+ llvm::Attribute MemoryAttr = llvm::Attribute::getWithMemoryEffects(
+ getLLVMContext(), llvm::MemoryEffects::writeOnly());
+ Attrs = Attrs.addFnAttribute(getLLVMContext(), MemoryAttr);
+ }
+}
+
/// Construct the IR attribute list of a function or call.
///
/// When adding an attribute, please consider where it should be handled:
@@ -5442,11 +5453,18 @@
/*AttrOnCallSite=*/true,
/*IsThunk=*/false);
- if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl))
+ if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurFuncDecl)) {
if (FD->hasAttr<StrictFPAttr>())
// All calls within a strictfp function are marked strictfp
Attrs = Attrs.addFnAttribute(getLLVMContext(), llvm::Attribute::StrictFP);
+ // If -ffast-math is enabled and the function is guarded by an
+ // '__attribute__((optnone)) adjust the memory attribute so the BE emits the
+ // library call instead of the intrinsic.
+ if (FD->hasAttr<OptimizeNoneAttr>() && getLangOpts().FastMath)
+ CGM.AdjustMemoryAttribute(CalleePtr->getName(), Callee.getAbstractInfo(),
+ Attrs);
+ }
// Add call-site nomerge attribute if exists.
if (InNoMergeAttributedStmt)
Attrs = Attrs.addFnAttribute(getLLVMContext(), llvm::Attribute::NoMerge);
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -2283,6 +2283,26 @@
const unsigned BuiltinIDIfNoAsmLabel =
FD->hasAttr<AsmLabelAttr>() ? 0 : BuiltinID;
+ bool ErrnoOverriden = false;
+ // True if math-errno is overriden via the
+ // '#pragma float_control(precise, on)'. This pragma disables fast-math,
+ // which implies math-errno.
+ if (E->hasStoredFPFeatures()) {
+ FPOptionsOverride OP = E->getFPFeatures();
+ if (OP.hasMathErrnoOverride())
+ ErrnoOverriden = OP.getMathErrnoOverride();
+ }
+ // True if 'atttibute__((optnone)) is used. This attibute overrides
+ // fast-math which implies math-errno.
+ bool OptNone = CurFuncDecl && CurFuncDecl->hasAttr<OptimizeNoneAttr>();
+
+ // True if we are compiling at -O2 and errno has been disabled
+ // using the '#pragma float_control(precise, off)', and
+ // attribute opt-none hasn't been seen.
+ bool ErrnoOverridenToFalseWithOpt =
+ !ErrnoOverriden && !OptNone &&
+ CGM.getCodeGenOpts().OptimizationLevel != 0;
+
// There are LLVM math intrinsics/instructions corresponding to math library
// functions except the LLVM op will never set errno while the math library
// might. Also, math builtins have the same semantics as their math library
@@ -2294,9 +2314,38 @@
getContext().BuiltinInfo.isConstWithoutErrnoAndExceptions(BuiltinID);
bool ConstWithoutExceptions =
getContext().BuiltinInfo.isConstWithoutExceptions(BuiltinID);
- if (FD->hasAttr<ConstAttr>() ||
- ((ConstWithoutErrnoAndExceptions || ConstWithoutExceptions) &&
- (!ConstWithoutErrnoAndExceptions || (!getLangOpts().MathErrno)))) {
+
+ // ConstAttr is enabled in fast-math mode. In fast-math mode, math-errno is
+ // disabled.
+ // Math intrinsics are generated only when math-errno is disabled. Any pragmas
+ // or attributes that affect math-errno should prevent or allow math
+ // intrincs to be generated. Intrinsics are generated:
+ // 1- In fast math mode, unless math-errno is overriden
+ // via '#pragma float_control(precise, on)', or via an
+ // 'attribute__((optnone))'.
+ // 2- If math-errno was enabled on command line but overriden
+ // to false via '#pragma float_control(precise, off))' and
+ // 'attribute__((optnone))' hasn't been used.
+ // 3- If we are compiling with optimization and errno has been disabled
+ // via '#pragma float_control(precise, off)', and
+ // 'attribute__((optnone))' hasn't been used.
+
+ bool ConstWithoutErrnoOrExceptions =
+ ConstWithoutErrnoAndExceptions || ConstWithoutExceptions;
+ bool GenerateIntrinsics =
+ FD->hasAttr<ConstAttr>() && !ErrnoOverriden && !OptNone;
+ if (!GenerateIntrinsics) {
+ GenerateIntrinsics =
+ ConstWithoutErrnoOrExceptions && !ConstWithoutErrnoAndExceptions;
+ if (!GenerateIntrinsics)
+ GenerateIntrinsics =
+ ConstWithoutErrnoOrExceptions &&
+ (!getLangOpts().MathErrno && !ErrnoOverriden && !OptNone);
+ if (!GenerateIntrinsics)
+ GenerateIntrinsics =
+ ConstWithoutErrnoOrExceptions && ErrnoOverridenToFalseWithOpt;
+ }
+ if (GenerateIntrinsics) {
switch (BuiltinIDIfNoAsmLabel) {
case Builtin::BIceil:
case Builtin::BIceilf:
Index: clang/include/clang/Basic/LangOptions.h
===================================================================
--- clang/include/clang/Basic/LangOptions.h
+++ clang/include/clang/Basic/LangOptions.h
@@ -854,6 +854,7 @@
setNoSignedZeroOverride(!Value);
setAllowReciprocalOverride(!Value);
setAllowApproxFuncOverride(!Value);
+ setMathErrnoOverride(Value);
if (Value)
/* Precise mode implies fp_contract=on and disables ffast-math */
setAllowFPContractWithinStatement();
Index: clang/include/clang/Basic/FPOptions.def
===================================================================
--- clang/include/clang/Basic/FPOptions.def
+++ clang/include/clang/Basic/FPOptions.def
@@ -26,5 +26,6 @@
OPTION(AllowApproxFunc, bool, 1, AllowReciprocal)
OPTION(FPEvalMethod, LangOptions::FPEvalMethodKind, 2, AllowApproxFunc)
OPTION(Float16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, FPEvalMethod)
-OPTION(BFloat16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, FPEvalMethod)
+OPTION(BFloat16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, Float16ExcessPrecision)
+OPTION(MathErrno, bool, 1, BFloat16ExcessPrecision)
#undef OPTION
Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -1724,7 +1724,7 @@
and ``fast``.
Details:
- * ``precise`` Disables optimizations that are not value-safe on floating-point data, although FP contraction (FMA) is enabled (``-ffp-contract=on``). This is the default behavior.
+ * ``precise`` Disables optimizations that are not value-safe on floating-point data, although FP contraction (FMA) is enabled (``-ffp-contract=on``). This is the default behavior. This value resets ``-fmath-errno`` to its target-dependent default.
* ``strict`` Enables ``-frounding-math`` and ``-ffp-exception-behavior=strict``, and disables contractions (FMA). All of the ``-ffast-math`` enablements are disabled. Enables ``STDC FENV_ACCESS``: by default ``FENV_ACCESS`` is disabled. This option setting behaves as though ``#pragma STDC FENV_ACCESS ON`` appeared at the top of the source file.
* ``fast`` Behaves identically to specifying both ``-ffast-math`` and ``ffp-contract=fast``
Index: clang/docs/LanguageExtensions.rst
===================================================================
--- clang/docs/LanguageExtensions.rst
+++ clang/docs/LanguageExtensions.rst
@@ -4695,7 +4695,12 @@
When ``pragma float_control(precise, on)`` is enabled, the section of code
governed by the pragma uses precise floating point semantics, effectively
``-ffast-math`` is disabled and ``-ffp-contract=on``
-(fused multiply add) is enabled.
+(fused multiply add) is enabled. This pragam enables ``-fmath-errno``.
+
+When ``pragma float_control(precise, off)`` is enabled, unsafe-floating point
+optimizations are enabled in the section of code governed by the pragma.
+Effectively ``-ffast-math`` is enabled and ``-ffp-contract=fast``. This pragam
+disables ``-fmath-errno``.
When ``pragma float_control(except, on)`` is enabled, the section of code
governed by the pragma behaves as though the command-line option
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