[Bug target/39942] Nonoptimal code - leaveq; xchg %ax,%ax; retq
jakub at gcc dot gnu dot org
gcc-bugzilla@gcc.gnu.org
Sat May 16 06:38:00 GMT 2009
------- Comment #45 from jakub at gcc dot gnu dot org 2009-05-16 06:37 -------
cmpl $1, %eax does have the modrm byte:
83 f8 01 cmp $0x1,%eax
compared to cmpl $0xdeadbeef, $eax which doesn't have it:
3d ef be ad de cmp $0xdeadbeef,%eax
So I think what I wrote is more precise. modrm byte is there if the insn has
ax_reg_operand destination and immediate source which hasn't been shortened.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39942
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