Bug 38373 - 32-bit Vortex degradation on PPC due to bad RTL aliasing
Summary: 32-bit Vortex degradation on PPC due to bad RTL aliasing
Status: VERIFIED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: rtl-optimization (show other bugs)
Version: 4.4.0
: P3 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords:
Depends on:
Blocks: 37515
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Reported: 2008-12-02 15:09 UTC by Luis Machado
Modified: 2009-06-29 02:25 UTC (History)
4 users (show)

See Also:
Host: powerpc*-*-*
Target: powerpc*-*-*
Build: powerpc*-*-*
Known to work:
Known to fail:
Last reconfirmed:


Attachments
Second part of the combined patch (389 bytes, patch)
2009-01-09 18:00 UTC, Luis Machado
Details | Diff

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Description Luis Machado 2008-12-02 15:09:39 UTC
The handling of LO_SUM by alias.c:find_base_term causes a degradation on 32-bit vortex on PPC when used with the new REG_POINTER attribute. 

Making "find_base_term" handle LO_SUM the same way as alias.c:find_base_value fixes the problem. Preventing "find_base_term" from returning NULL so easily also fixes the problem.

A fix for 4.5 will most probably be a combination of these two approaches.
Comment 1 Luis Machado 2009-01-09 18:00:04 UTC
Created attachment 17065 [details]
Second part of the combined patch

Additional check to avoid returning a NULL base. This is a placeholder for a 4.5 fix.
Comment 2 Paolo Bonzini 2009-02-03 14:00:21 UTC
Is this a regression?  I don't see anything in the patches or in their description that would prevent a backport to 4.4.
Comment 3 Luis Machado 2009-04-30 16:33:32 UTC
This is already in 4.4, but we would like to add additional checks on 4.5 that would be risky to have on 4.4 (since it was almost being released). I have the additional patch and will attach it soon.

Sorry it took so long to reply.

Luis
Comment 4 Steven Bosscher 2009-06-04 12:52:48 UTC
This is one of the "GCC 4.5 pending patches". Now would be a good time to do something with this patch -- like, submitting it.
Comment 5 Luis Machado 2009-06-29 02:24:41 UTC
Already commited on 4.5. Closing...
Comment 6 Luis Machado 2009-06-29 02:25:14 UTC
Fixed