[Hexagon] Set -ffp-contract=fast at -O3 unless explicitly specified

llvm-svn: 301361

clang/lib/Driver/ToolChains/Hexagon.cpp

@@ -402,6 +402,39 @@ Tool *HexagonToolChain::buildLinker() const {
   return new tools::hexagon::Linker(*this);
 }
 
+unsigned HexagonToolChain::getOptimizationLevel(
+    const llvm::opt::ArgList &DriverArgs) const {
+  // Copied in large part from lib/Frontend/CompilerInvocation.cpp.
+  Arg *A = DriverArgs.getLastArg(options::OPT_O_Group);
+  if (!A)
+    return 0;
+
+  if (A->getOption().matches(options::OPT_O0))
+    return 0;
+  if (A->getOption().matches(options::OPT_Ofast))
+    return 3;
+  assert(A->getNumValues() != 0);
+  StringRef S(A->getValue());
+  if (S == "s" || S == "z" || S.empty())
+    return 2;
+  if (S == "g")
+    return 1;
+
+  unsigned OptLevel;
+  if (S.getAsInteger(10, OptLevel))
+    return 0;
+  return OptLevel;
+}
+
+void HexagonToolChain::addClangTargetOptions(const ArgList &DriverArgs,
+                                             ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_ffp_contract))
+    return;
+  unsigned OptLevel = getOptimizationLevel(DriverArgs);
+  if (OptLevel >= 3)
+    CC1Args.push_back("-ffp-contract=fast");
+}
+
 void HexagonToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                                  ArgStringList &CC1Args) const {
   if (DriverArgs.hasArg(options::OPT_nostdinc) ||

clang/lib/Driver/ToolChains/Hexagon.h

@@ -61,11 +61,15 @@ protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
 
+  unsigned getOptimizationLevel(const llvm::opt::ArgList &DriverArgs) const;
+
 public:
   HexagonToolChain(const Driver &D, const llvm::Triple &Triple,
                    const llvm::opt::ArgList &Args);
   ~HexagonToolChain() override;
 
+  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
+                             llvm::opt::ArgStringList &CC1Args) const override;
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;

clang/test/Driver/hexagon-toolchain-elf.c

@@ -97,6 +97,22 @@
 // CHECK024: "-cc1" {{.*}} "-target-cpu" "hexagonv62"
 // CHECK024: hexagon-link{{.*}}/Inputs/hexagon_tree/Tools/bin/../target/hexagon/lib/v62/crt0
 
+// RUN: %clang -### -target hexagon-unknown-elf \
+// RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
+// RUN:   -O3 \
+// RUN:   %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK025 %s
+// CHECK025: "-ffp-contract=fast"
+// CHECK025: hexagon-link
+
+// RUN: %clang -### -target hexagon-unknown-elf \
+// RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
+// RUN:   -O3 -ffp-contract=off \
+// RUN:   %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK026 %s
+// CHECK026-NOT: "-ffp-contract=fast"
+// CHECK026: hexagon-link
+
 // -----------------------------------------------------------------------------
 // Test Linker related args
 // -----------------------------------------------------------------------------