[Bug rtl-optimization/38373] New: 32-bit Vortex degradation on PPC due to bad RTL aliasing

[Bug rtl-optimization/38373] New: 32-bit Vortex degradation on PPC due to bad RTL aliasing

[luisgpm at linux dot vnet dot ibm dot com]

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.


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           Summary: 32-bit Vortex degradation on PPC due to bad RTL aliasing
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: luisgpm at linux dot vnet dot ibm dot com
 GCC build triplet: powerpc*-*-*
  GCC host triplet: powerpc*-*-*
GCC target triplet: powerpc*-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[luisgpm at linux dot vnet dot ibm dot com]

------- Comment #1 from luisgpm at linux dot vnet dot ibm dot com  2009-01-09 18:00 -------
Created an attachment (id=17065)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17065&action=view)
Second part of the combined patch

Additional check to avoid returning a NULL base. This is a placeholder for a
4.5 fix.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[bonzini at gnu dot org]

------- Comment #2 from bonzini at gnu dot org  2009-02-03 14:00 -------
Is this a regression?  I don't see anything in the patches or in their
description that would prevent a backport to 4.4.


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bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[luisgpm at linux dot vnet dot ibm dot com]

------- Comment #3 from luisgpm at linux dot vnet dot ibm dot com  2009-04-30 16:33 -------
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


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[steven at gcc dot gnu dot org]

------- Comment #4 from steven at gcc dot gnu dot org  2009-06-04 12:52 -------
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.


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steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[luisgpm at linux dot vnet dot ibm dot com]

------- Comment #5 from luisgpm at linux dot vnet dot ibm dot com  2009-06-29 02:24 -------
Already commited on 4.5. Closing...


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luisgpm at linux dot vnet dot ibm dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373

[Bug rtl-optimization/38373] 32-bit Vortex degradation on PPC due to bad RTL aliasing

[luisgpm at linux dot vnet dot ibm dot com]

------- Comment #6 from luisgpm at linux dot vnet dot ibm dot com  2009-06-29 02:25 -------
Fixed


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luisgpm at linux dot vnet dot ibm dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |VERIFIED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38373