[IR][CodeGen] Remove unsafe-fp-math attribute support

Author: paperchalice

clang/lib/CodeGen/BackendUtil.cpp

@@ -430,12 +430,6 @@ static bool initTargetOptions(const CompilerInstance &CI,
   Options.NoInfsFPMath = LangOpts.NoHonorInfs;
   Options.NoNaNsFPMath = LangOpts.NoHonorNaNs;
   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
-  Options.UnsafeFPMath = LangOpts.AllowFPReassoc && LangOpts.AllowRecip &&
-                         LangOpts.NoSignedZero && LangOpts.ApproxFunc &&
-                         (LangOpts.getDefaultFPContractMode() ==
-                              LangOptions::FPModeKind::FPM_Fast ||
-                          LangOpts.getDefaultFPContractMode() ==
-                              LangOptions::FPModeKind::FPM_FastHonorPragmas);
 
   Options.BBAddrMap = CodeGenOpts.BBAddrMap;
   Options.BBSections =

llvm/docs/CommandGuide/llc.rst

@@ -125,13 +125,6 @@ End-user Options
 
  Enable setting the FP exceptions build attribute not to use exceptions.
 
-.. option:: --enable-unsafe-fp-math
-
- Enable optimizations that make unsafe assumptions about IEEE math (e.g. that
- addition is associative) or may not work for all input ranges.  These
- optimizations allow the code generator to make use of some instructions which
- would otherwise not be usable (such as ``fsin`` on X86).
-
 .. option:: --stats
 
  Print statistics recorded by code-generation passes.

llvm/docs/CommandGuide/lli.rst

@@ -107,11 +107,6 @@ FLOATING POINT OPTIONS
 
  Enable optimizations that assume no NAN values.
 
-.. option:: -enable-unsafe-fp-math
-
- Causes :program:`lli` to enable optimizations that may decrease floating point
- precision.
-
 .. option:: -soft-float
 
  Causes :program:`lli` to generate software floating point library calls instead of

llvm/include/llvm/CodeGen/CommandFlags.h

@@ -58,8 +58,6 @@ LLVM_ABI CodeGenFileType getFileType();
 
 LLVM_ABI FramePointerKind getFramePointerUsage();
 
-LLVM_ABI bool getEnableUnsafeFPMath();
-
 LLVM_ABI bool getEnableNoInfsFPMath();
 
 LLVM_ABI bool getEnableNoNaNsFPMath();

llvm/include/llvm/IR/Attributes.td

@@ -410,7 +410,6 @@ def LessPreciseFPMAD : StrBoolAttr<"less-precise-fpmad">;
 def NoInfsFPMath : StrBoolAttr<"no-infs-fp-math">;
 def NoNansFPMath : StrBoolAttr<"no-nans-fp-math">;
 def NoSignedZerosFPMath : StrBoolAttr<"no-signed-zeros-fp-math">;
-def UnsafeFPMath : StrBoolAttr<"unsafe-fp-math">;
 def NoJumpTables : StrBoolAttr<"no-jump-tables">;
 def NoInlineLineTables : StrBoolAttr<"no-inline-line-tables">;
 def ProfileSampleAccurate : StrBoolAttr<"profile-sample-accurate">;
@@ -474,7 +473,6 @@ def : MergeRule<"setAND<LessPreciseFPMADAttr>">;
 def : MergeRule<"setAND<NoInfsFPMathAttr>">;
 def : MergeRule<"setAND<NoNansFPMathAttr>">;
 def : MergeRule<"setAND<NoSignedZerosFPMathAttr>">;
-def : MergeRule<"setAND<UnsafeFPMathAttr>">;
 def : MergeRule<"setOR<NoImplicitFloatAttr>">;
 def : MergeRule<"setOR<NoJumpTablesAttr>">;
 def : MergeRule<"setOR<ProfileSampleAccurateAttr>">;

llvm/include/llvm/Target/TargetOptions.h

@@ -118,9 +118,8 @@ enum CodeObjectVersionKind {
 class TargetOptions {
 public:
   TargetOptions()
-      : UnsafeFPMath(false), NoInfsFPMath(false), NoNaNsFPMath(false),
-        NoTrappingFPMath(true), NoSignedZerosFPMath(false),
-        EnableAIXExtendedAltivecABI(false),
+      : NoInfsFPMath(false), NoNaNsFPMath(false), NoTrappingFPMath(true),
+        NoSignedZerosFPMath(false), EnableAIXExtendedAltivecABI(false),
         HonorSignDependentRoundingFPMathOption(false), NoZerosInBSS(false),
         GuaranteedTailCallOpt(false), StackSymbolOrdering(true),
         EnableFastISel(false), EnableGlobalISel(false), UseInitArray(false),
@@ -156,13 +155,6 @@ class TargetOptions {
   /// MCAsmInfo::BinutilsVersion.
   std::pair<int, int> BinutilsVersion{0, 0};
 
-  /// UnsafeFPMath - This flag is enabled when the
-  /// -enable-unsafe-fp-math flag is specified on the command line.  When
-  /// this flag is off (the default), the code generator is not allowed to
-  /// produce results that are "less precise" than IEEE allows.  This includes
-  /// use of X86 instructions like FSIN and FCOS instead of libcalls.
-  unsigned UnsafeFPMath : 1;
-
   /// NoInfsFPMath - This flag is enabled when the
   /// -enable-no-infs-fp-math flag is specified on the command line. When
   /// this flag is off (the default), the code generator is not allowed to

llvm/lib/CodeGen/CommandFlags.cpp

@@ -64,7 +64,6 @@ CGOPT_EXP(uint64_t, LargeDataThreshold)
 CGOPT(ExceptionHandling, ExceptionModel)
 CGOPT_EXP(CodeGenFileType, FileType)
 CGOPT(FramePointerKind, FramePointerUsage)
-CGOPT(bool, EnableUnsafeFPMath)
 CGOPT(bool, EnableNoInfsFPMath)
 CGOPT(bool, EnableNoNaNsFPMath)
 CGOPT(bool, EnableNoSignedZerosFPMath)
@@ -219,12 +218,6 @@ codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
                      "Enable frame pointer elimination")));
   CGBINDOPT(FramePointerUsage);
 
-  static cl::opt<bool> EnableUnsafeFPMath(
-      "enable-unsafe-fp-math",
-      cl::desc("Enable optimizations that may decrease FP precision"),
-      cl::init(false));
-  CGBINDOPT(EnableUnsafeFPMath);
-
   static cl::opt<bool> EnableNoInfsFPMath(
       "enable-no-infs-fp-math",
       cl::desc("Enable FP math optimizations that assume no +-Infs"),
@@ -552,7 +545,6 @@ TargetOptions
 codegen::InitTargetOptionsFromCodeGenFlags(const Triple &TheTriple) {
   TargetOptions Options;
   Options.AllowFPOpFusion = getFuseFPOps();
-  Options.UnsafeFPMath = getEnableUnsafeFPMath();
   Options.NoInfsFPMath = getEnableNoInfsFPMath();
   Options.NoNaNsFPMath = getEnableNoNaNsFPMath();
   Options.NoSignedZerosFPMath = getEnableNoSignedZerosFPMath();
@@ -706,7 +698,6 @@ void codegen::setFunctionAttributes(StringRef CPU, StringRef Features,
   if (getStackRealign())
     NewAttrs.addAttribute("stackrealign");
 
-  HANDLE_BOOL_ATTR(EnableUnsafeFPMathView, "unsafe-fp-math");
   HANDLE_BOOL_ATTR(EnableNoInfsFPMathView, "no-infs-fp-math");
   HANDLE_BOOL_ATTR(EnableNoNaNsFPMathView, "no-nans-fp-math");
   HANDLE_BOOL_ATTR(EnableNoSignedZerosFPMathView, "no-signed-zeros-fp-math");

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -17462,9 +17462,9 @@ SDValue DAGCombiner::visitFSUBForFMACombine(SDNode *N) {
   // fold (fsub (fpext (fneg (fmul, x, y))), z)
   //   -> (fneg (fma (fpext x), (fpext y), z))
   // Note: This could be removed with appropriate canonicalization of the
-  // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However, the
-  // orthogonal flags -fp-contract=fast and -enable-unsafe-fp-math prevent
-  // from implementing the canonicalization in visitFSUB.
+  // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However,
+  // -fp-contract=fast prevent from implementing the canonicalization
+  // in visitFSUB.
   if (matcher.match(N0, ISD::FP_EXTEND)) {
     SDValue N00 = N0.getOperand(0);
     if (matcher.match(N00, ISD::FNEG)) {
@@ -17486,9 +17486,9 @@ SDValue DAGCombiner::visitFSUBForFMACombine(SDNode *N) {
   // fold (fsub (fneg (fpext (fmul, x, y))), z)
   //   -> (fneg (fma (fpext x)), (fpext y), z)
   // Note: This could be removed with appropriate canonicalization of the
-  // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However, the
-  // orthogonal flags -fp-contract=fast and -enable-unsafe-fp-math prevent
-  // from implementing the canonicalization in visitFSUB.
+  // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However,
+  // -fp-contract=fast prevent from implementing the canonicalization
+  // in visitFSUB.
   if (matcher.match(N0, ISD::FNEG)) {
     SDValue N00 = N0.getOperand(0);
     if (matcher.match(N00, ISD::FP_EXTEND)) {

llvm/lib/CodeGen/TargetOptionsImpl.cpp

@@ -51,7 +51,7 @@ bool TargetOptions::FramePointerIsReserved(const MachineFunction &MF) const {
 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
 /// that the rounding mode of the FPU can change from its default.
 bool TargetOptions::HonorSignDependentRoundingFPMath() const {
-  return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
+  return HonorSignDependentRoundingFPMathOption;
 }
 
 /// NOTE: There are targets that still do not support the debug entry values

llvm/lib/Target/TargetMachine.cpp

@@ -158,7 +158,6 @@ void TargetMachine::resetTargetOptions(const Function &F) const {
     Options.X = F.getFnAttribute(Y).getValueAsBool();     \
   } while (0)
 
-  RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
   RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
   RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
   RESET_OPTION(NoSignedZerosFPMath, "no-signed-zeros-fp-math");