* config/i386/i386.h (TARGET_SAHF): New define.
* config/i386/i386.c (ix86_tune_features) [X86_TUNE_USE_SAHF]:
Also enable for m_K8, m_AMDFAM10 and m_CORE2.
(x86_sahf): New global variable.
(override_options): Add PTA_NO_SAHF to pta_flags enum. Recode
pta_flags masks using shifts. Add PTA_NO_SAHF to x86_64 and
nocona processor flags. Set x86_sahf when PTA_NO_SAHF is not set
in processor flags. Do not unconditionally disable TARGET_USE_SAHF
for 64-bit.
(ix86_fp_comparison_sahf_cost): Return high value for !TARGET_SAHF.
(ix86_expand_fp_compare): Check for TARGET_CMOVE or TARGET_SAHF
when expanding fcomi/sahf based tests.
(ix86_emit_fp_unordered_jump): Check for TARGET_SAHF when
expanding sahf based alternative. Emit sahf based sequence when
optimizing for code size.
* config/i386/i386.md (x86_sahf_1): Do not disable for
TARGET_64BIT, enable for TARGET_SAHF.