Add -ffp-contract = { fast | on | off } command line option support.
This flag sets the 'fp-contract' mode, which controls the formation of fused
floating point operations. Available modes are:
- Fast: Form fused operations anywhere.
- On: Form fused operations where allowed by FP_CONTRACT. This is the default
mode.
- Off: Don't form fused operations (in future this may be relaxed to forming
fused operations where it can be proved that the result won't be
affected).
Currently clang doesn't support the FP_CONTRACT pragma, so the 'On' and 'Off'
modes are equivalent.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159794 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 5a97875..0a1915b 100644
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -351,6 +351,19 @@
Options.FloatABIType = llvm::FloatABI::Default;
}
+ // Set FP fusion mode.
+ switch (LangOpts.getFPContractMode()) {
+ case LangOptions::FPC_Off:
+ Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
+ break;
+ case LangOptions::FPC_On:
+ Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
+ break;
+ case LangOptions::FPC_Fast:
+ Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
+ break;
+ }
+
Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 98beb22..dd198a1 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1805,6 +1805,24 @@
!TrappingMath)
CmdArgs.push_back("-menable-unsafe-fp-math");
+
+ // Validate and pass through -fp-contract option.
+ if (Arg *A = Args.getLastArg(options::OPT_ffast_math,
+ options::OPT_ffp_contract)) {
+ if (A->getOption().getID() == options::OPT_ffp_contract) {
+ StringRef Val = A->getValue(Args);
+ if (Val == "fast" || Val == "on" || Val == "off") {
+ CmdArgs.push_back(Args.MakeArgString("-ffp-contract=" + Val));
+ } else {
+ D.Diag(diag::err_drv_unsupported_option_argument)
+ << A->getOption().getName() << Val;
+ }
+ } else { // A is OPT_ffast_math
+ // If fast-math is set then set the fp-contract mode to fast.
+ CmdArgs.push_back(Args.MakeArgString("-ffp-contract=fast"));
+ }
+ }
+
// We separately look for the '-ffast-math' flag, and if we find it, tell the
// frontend to provide the appropriate preprocessor macros. This is distinct
// from enabling any optimizations as it induces a language change which must
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 943cb20..cf08913 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -759,6 +759,11 @@
Res.push_back("-ftrapv-handler", Opts.OverflowHandler);
break;
}
+ switch (Opts.getFPContractMode()) {
+ case LangOptions::FPC_Off: Res.push_back("-ffp-contract=off"); break;
+ case LangOptions::FPC_On: Res.push_back("-ffp-contract=on"); break;
+ case LangOptions::FPC_Fast: Res.push_back("-ffp-contract=fast"); break;
+ }
if (Opts.HeinousExtensions)
Res.push_back("-fheinous-gnu-extensions");
// Optimize is implicit.
@@ -1975,6 +1980,18 @@
Diags.Report(diag::err_drv_invalid_value)
<< Args.getLastArg(OPT_fvisibility)->getAsString(Args) << Vis;
+ if (Arg *A = Args.getLastArg(OPT_ffp_contract)) {
+ StringRef Val = A->getValue(Args);
+ if (Val == "fast")
+ Opts.setFPContractMode(LangOptions::FPC_Fast);
+ else if (Val == "on")
+ Opts.setFPContractMode(LangOptions::FPC_On);
+ else if (Val == "off")
+ Opts.setFPContractMode(LangOptions::FPC_Off);
+ else
+ Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Val;
+ }
+
if (Args.hasArg(OPT_fvisibility_inlines_hidden))
Opts.InlineVisibilityHidden = 1;