From a81169d8fa4382d7d4e702323096358dd31e174a Mon Sep 17 00:00:00 2001 From: Jan Hubicka Date: Wed, 9 Oct 2013 01:33:34 +0200 Subject: [PATCH] i386.c (ix86_option_override_internal): Switch to SSE math for -ffast-math when target ISA supports SSE2. * config/i386/i386.c (ix86_option_override_internal): Switch to SSE math for -ffast-math when target ISA supports SSE2. From-SVN: r203291 --- gcc/ChangeLog | 5 +++++ gcc/config/i386/i386.c | 13 +++++++++++++ 2 files changed, 18 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d5bc285e92f..fa1ef08d9ba 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2013-10-08 Jan Hubicka + + * config/i386/i386.c (ix86_option_override_internal): Switch + to SSE math for -ffast-math when target ISA supports SSE2. + 2013-10-08 Andrew MacLeod * tree-flow.h: Remove some prototypes. diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 1713ad6f06d..168a2ac50ea 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -3769,6 +3769,19 @@ ix86_option_override_internal (bool main_args_p) } } } + /* For all chips supporting SSE2, -mfpmath=sse performs better than + fpmath=387. The second is however default at many targets since the + extra 80bit precision of temporaries is considered to be part of ABI. + Overwrite the default at least for -ffast-math. + TODO: -mfpmath=both seems to produce same performing code with bit + smaller binaries. It is however not clear if register allocation is + ready for this setting. + Also -mfpmath=387 is overall a lot more compact (bout 4-5%) than SSE + codegen. We may switch to 387 with -ffast-math for size optimized + functions. */ + else if (fast_math_flags_set_p (&global_options) + && TARGET_SSE2) + ix86_fpmath = FPMATH_SSE; else ix86_fpmath = TARGET_FPMATH_DEFAULT; -- 2.30.2