[Bug rtl-optimization/63620] RELOAD lost SET_GOT dependency on Darwin
evstupac at gmail dot com
Mon Oct 27 12:10:00 GMT 2014
--- Comment #10 from Stupachenko Evgeny <evstupac at gmail dot com> ---
(In reply to Uroš Bizjak from comment #9)
> (In reply to Stupachenko Evgeny from comment #8)
> > (In reply to Uroš Bizjak from comment #7)
> > > The difference si that the call to f128_p3 does not expand with "use (reg:SI
> > > bx)" tag in the Darwin case. Probably ix86_expand_call should be fixed for
> > > TARGET_MACHO
> > Darwin generates indirect access throw generated section: .symbol_stub.
> > They don't use EBX in the call even without any changes (relaxing EBX usage).
> I guess that the mentioned "use" in the call is what keeps PIC register live
> accross push in the non-Darwin case.
Not sure I understand Darwin features correct, but they push shifted esp to
(objdump of example for PR63618)
d20: 56 push %esi
d21: 83 ec 18 sub $0x18,%esp
d24: 66 0f 6f 44 24 30 movdqa 0x30(%esp),%xmm0
d2a: 89 e0 mov %esp,%eax
d2c: 83 ec 2c sub $0x2c,%esp
d2f: 8b 74 24 4c mov 0x4c(%esp),%esi
d33: 0f 11 44 24 1c movups %xmm0,0x1c(%esp)
d38: 0f 11 44 24 0c movups %xmm0,0xc(%esp)
d3d: 50 push %eax
d3e: e8 f9 00 00 00 call e3c <___multf3$stub>
d43: 89 f0 mov %esi,%eax
d45: 66 0f 6f 4c 24 2c movdqa 0x2c(%esp),%xmm1
d4b: 0f 29 0e movaps %xmm1,(%esi)
d4e: 83 c4 44 add $0x44,%esp
d51: 5e pop %esi
d52: c2 04 00 ret $0x4
Anyway, if call is not EBX dependent (say local call in Linux) the issue is not
reproduced (like in example from PR63618).
So the issue looks like Darwin dependent RA issue.
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