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[Bug middle-end/55142] [4.8 Regression] internal compiler error: in plus_constant, at explow.c:88
- From: "hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 09 Nov 2012 00:35:28 +0000
- Subject: [Bug middle-end/55142] [4.8 Regression] internal compiler error: in plus_constant, at explow.c:88
- Auto-submitted: auto-generated
- References: <bug-55142-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55142
--- Comment #30 from H.J. Lu <hjl.tools at gmail dot com> 2012-11-09 00:35:28 UTC ---
(In reply to comment #24)
>
> I think the most robust solution would be to always zero-extend the addresses
> for -mx32, i.e. output
> movl %ecx, -1073743664(%eax)
> even if the address is a PLUS in DImode. Otherwise, we're left with kludges...
Since x32 runs in 64-bit mode, for address -0x40000300(%rax),
hardware sign-extends displacement from 32-bits to 64-bits and
adds it to %rax. But x32 wants 32-bit -0x40000300, not 64-bit
-0x40000300. I believe it is correct for GCC to use 32-bit
registers instead of 64-bit registers when displacement is
negative.