Use FPContractModeKind universally

FPContractModeKind is the codegen option flag which is already ternary (off,
on, fast).  This makes it universally the type for the contractable info
across the front-end:

* In FPOptions (i.e. in the Sema + in the expression nodes).
* In LangOpts::DefaultFPContractMode which is the option that initializes
FPOptions in the Sema.

Another way to look at this change is that before fp-contractable on/off were
the only states handled to the front-end:
 * For "on", FMA folding was performed by  the front-end
 * For "fast", we simply forwarded the flag to TargetOptions to handle it in
 LLVM

Now off/on/fast are all exposed because for fast we will generate
fast-math-flags during CodeGen.

This is toward moving fp-contraction=fast from an LLVM TargetOption to a
FastMathFlag in order to fix PR25721.

Differential Revision: https://reviews.llvm.org/D31167

llvm-svn: 299027

4 files changed, 27 insertions, 30 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 35de1a4580e..f34c8cabc69 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -561,14 +561,14 @@ void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
           .Default(llvm::FloatABI::Default);
 
   // Set FP fusion mode.
-  switch (CodeGenOpts.getFPContractMode()) {
-  case CodeGenOptions::FPC_Off:
+  switch (LangOpts.getDefaultFPContractMode()) {
+  case LangOptions::FPC_Off:
     Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
     break;
-  case CodeGenOptions::FPC_On:
+  case LangOptions::FPC_On:
     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
     break;
-  case CodeGenOptions::FPC_Fast:
+  case LangOptions::FPC_Fast:
     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
     break;
   }
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 9eb21b8086f..e9041b282fb 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -2672,12 +2672,7 @@ static Value* tryEmitFMulAdd(const BinOpInfo &op,
          "Only fadd/fsub can be the root of an fmuladd.");
 
   // Check whether this op is marked as fusable.
-  if (!op.FPFeatures.isFPContractable())
-    return nullptr;
-
-  // Check whether -ffp-contract=on. (If -ffp-contract=off/fast, fusing is
-  // either disabled, or handled entirely by the LLVM backend).
-  if (CGF.CGM.getCodeGenOpts().getFPContractMode() != CodeGenOptions::FPC_On)
+  if (!op.FPFeatures.allowFPContractWithinStatement())
     return nullptr;
 
   // We have a potentially fusable op. Look for a mul on one of the operands.
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index ab2ba9287c8..0c1d6d0d854 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -816,18 +816,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     }
   }
 
-  if (Arg *A = Args.getLastArg(OPT_ffp_contract)) {
-    StringRef Val = A->getValue();
-    if (Val == "fast")
-      Opts.setFPContractMode(CodeGenOptions::FPC_Fast);
-    else if (Val == "on")
-      Opts.setFPContractMode(CodeGenOptions::FPC_On);
-    else if (Val == "off")
-      Opts.setFPContractMode(CodeGenOptions::FPC_Off);
-    else
-      Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
-  }
-
   if (Arg *A = Args.getLastArg(OPT_fdenormal_fp_math_EQ)) {
     StringRef Val = A->getValue();
     if (Val == "ieee")
@@ -1647,7 +1635,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
     Opts.AltiVec = 0;
     Opts.ZVector = 0;
     Opts.LaxVectorConversions = 0;
-    Opts.DefaultFPContract = 1;
+    Opts.setDefaultFPContractMode(LangOptions::FPC_On);
     Opts.NativeHalfType = 1;
     Opts.NativeHalfArgsAndReturns = 1;
     // Include default header file for OpenCL.
@@ -1658,6 +1646,9 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
 
   Opts.CUDA = IK == IK_CUDA || IK == IK_PreprocessedCuda ||
               LangStd == LangStandard::lang_cuda;
+  if (Opts.CUDA)
+    // Set default FP_CONTRACT to FAST.
+    Opts.setDefaultFPContractMode(LangOptions::FPC_Fast);
 
   Opts.RenderScript = IK == IK_RenderScript;
   if (Opts.RenderScript) {
@@ -2282,6 +2273,18 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                       Args.hasArg(OPT_cl_unsafe_math_optimizations) ||
                       Args.hasArg(OPT_cl_fast_relaxed_math);
 
+  if (Arg *A = Args.getLastArg(OPT_ffp_contract)) {
+    StringRef Val = A->getValue();
+    if (Val == "fast")
+      Opts.setDefaultFPContractMode(LangOptions::FPC_Fast);
+    else if (Val == "on")
+      Opts.setDefaultFPContractMode(LangOptions::FPC_On);
+    else if (Val == "off")
+      Opts.setDefaultFPContractMode(LangOptions::FPC_Off);
+    else
+      Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
+  }
+
   Opts.RetainCommentsFromSystemHeaders =
       Args.hasArg(OPT_fretain_comments_from_system_headers);
 
@@ -2536,10 +2539,6 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
     // triple used for host compilation.
     if (LangOpts.CUDAIsDevice)
       Res.getTargetOpts().HostTriple = Res.getFrontendOpts().AuxTriple;
-
-    // Set default FP_CONTRACT to FAST.
-    if (!Args.hasArg(OPT_ffp_contract))
-      Res.getCodeGenOpts().setFPContractMode(CodeGenOptions::FPC_Fast);
   }
 
   // FIXME: Override value name discarding when asan or msan is used because the
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 992eac9019f..34744cbdd99 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -450,13 +450,16 @@ void Sema::ActOnPragmaVisibility(const IdentifierInfo* VisType,
 void Sema::ActOnPragmaFPContract(tok::OnOffSwitch OOS) {
   switch (OOS) {
   case tok::OOS_ON:
-    FPFeatures.setFPContractable(true);
+    FPFeatures.setAllowFPContractWithinStatement();
     break;
   case tok::OOS_OFF:
-    FPFeatures.setFPContractable(false);
+    FPFeatures.setDisallowFPContract();
     break;
   case tok::OOS_DEFAULT:
-    FPFeatures.setFPContractable(getLangOpts().DefaultFPContract);
+    if (getLangOpts().getDefaultFPContractMode() == LangOptions::FPC_On)
+      FPFeatures.setAllowFPContractWithinStatement();
+    else
+      FPFeatures.setDisallowFPContract();
     break;
   }
 }