3 files changed, 12 insertions, 7 deletions
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 59196b20e28..e07068aea14 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1823,12 +1823,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
-  // 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
-  // survive serialization and deserialization, etc.
+  // We separately look for the '-ffast-math' and '-ffinite-math-only' flags,
+  // and if we find them, tell the frontend to provide the appropriate
+  // preprocessor macros. This is distinct from enabling any optimizations as
+  // these options induce language changes which must survive serialization
+  // and deserialization, etc.
   if (Args.hasArg(options::OPT_ffast_math))
     CmdArgs.push_back("-ffast-math");
+  if (Args.hasArg(options::OPT_ffinite_math_only))
+    CmdArgs.push_back("-ffinite-math-only");
 
   // Decide whether to use verbose asm. Verbose assembly is the default on
   // toolchains which have the integrated assembler on by default.
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 016783b1dc5..544c0a270a0 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2100,6 +2100,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NoInlineDefine = !Opt || Args.hasArg(OPT_fno_inline);
 
   Opts.FastMath = Args.hasArg(OPT_ffast_math);
+  Opts.FiniteMathOnly = Args.hasArg(OPT_ffinite_math_only);
 
   unsigned SSP = Args.getLastArgIntValue(OPT_stack_protector, 0, Diags);
   switch (SSP) {
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 6120d117e3c..3979731ff6f 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -527,9 +527,10 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (const char *Prefix = TI.getUserLabelPrefix())
     Builder.defineMacro("__USER_LABEL_PREFIX__", Prefix);
 
-  // Build configuration options.  FIXME: these should be controlled by
-  // command line options or something.
-  Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
+  if (LangOpts.FastMath || LangOpts.FiniteMathOnly)
+    Builder.defineMacro("__FINITE_MATH_ONLY__", "1");
+  else
+    Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
 
   if (LangOpts.GNUInline)
     Builder.defineMacro("__GNUC_GNU_INLINE__");