------- Comment #2 from ubizjak at gmail dot com 2010-04-12 17:11 -------
configure should detect if assembler supports sahf mnemonic.
In your build directory, check gcc/config.log for:
configure:23019: checking assembler for sahf mnemonic
configure:23028: /usr/local/x86_64-unknown-linux-gnu/bin/as -o conftest.o
conftest.s >&5
configure:23031: $? = 0
configure:23042: result: yes
Based on this result, gcc outputs:
(define_insn "x86_sahf_1"
[(set (reg:CC FLAGS_REG)
(unspec:CC [(match_operand:HI 0 "register_operand" "a")]
UNSPEC_SAHF))]
"TARGET_SAHF"
{
#ifdef HAVE_AS_IX86_SAHF
return "sahf";
#else
return ASM_BYTE "0x9e";
#endif
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43733
