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.

llvm-svn: 159794

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index 4eed4aa06f3..b74b2855014 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -29,3 +29,9 @@
 // RUN: %clang -### -c -Wdeprecated %s 2>&1 | FileCheck -check-prefix=DEPRECATED-OFF-CHECK %s
 // DEPRECATED-ON-CHECK: -fdeprecated-macro
 // DEPRECATED-OFF-CHECK-NOT: -fdeprecated-macro
+
+// RUN: %clang -### -S -ffp-contract=fast %s 2>&1 | FileCheck -check-prefix=FP-CONTRACT-FAST-CHECK %s
+// RUN: %clang -### -S -ffast-math %s 2>&1 | FileCheck -check-prefix=FP-CONTRACT-FAST-CHECK %s
+// RUN: %clang -### -S -ffp-contract=off %s 2>&1 | FileCheck -check-prefix=FP-CONTRACT-OFF-CHECK %s
+// FP-CONTRACT-FAST-CHECK: -ffp-contract=fast
+// FP-CONTRACT-OFF-CHECK: -ffp-contract=off