Re: [PATCH] Fix issue with RTL alias-export and promoted subregs

[Uros Bizjak <ubizjak at gmail dot com>]

Hello!

> It happens that with promoted subregs we have to deal with
> MEMs like [9 p_initial+-4 S8 A64] which access 8 bytes starting
> 4 bytes before a decl with 4 bytes in size.  Not very nice.
>
> Fixed like the following.  Bootstrapped and tested on
> x86_64-unknown-linux-gnu and ppc64 (by Pat).
>
> Applied to trunk.
>
> Richard.
>
> 2009-09-23  Richard Guenther<rguenther@suse.de>
>
> 	* alias.c (ao_ref_from_mem): Correct for negative MEM_OFFSET
> 	produced for bigendian targets with promoted subregs.
>    

This patch breaks a couple of testcases on alpha-linux-gnu [1]:

FAIL: gcc.c-torture/execute/20030408-1.c compilation,  -O3 -fomit-frame-pointer  (internal compiler error)
UNRESOLVED: gcc.c-torture/execute/20030408-1.c execution,  -O3 -fomit-frame-pointer
FAIL: gcc.c-torture/execute/20030408-1.c compilation,  -O3 -g  (internal compiler error)
UNRESOLVED: gcc.c-torture/execute/20030408-1.c execution,  -O3 -g
FAIL: gcc.c-torture/execute/pr27285.c compilation,  -O1  (internal compiler error)
UNRESOLVED: gcc.c-torture/execute/pr27285.c execution,  -O1
FAIL: gcc.c-torture/execute/pr27285.c compilation,  -O2  (internal compiler error)
UNRESOLVED: gcc.c-torture/execute/pr27285.c execution,  -O2
FAIL: gcc.c-torture/execute/pr27285.c compilation,  -Os  (internal compiler error)
UNRESOLVED: gcc.c-torture/execute/pr27285.c execution,  -Os


This failure can be reproduced by a cross (from x86_64-pc-linux-gnu):

~/gcc-build-alpha/gcc/cc1 -O2 -quiet pr27285.c
pr27285.c: In function âmainâ:
pr27285.c:46:1: internal compiler error: in ao_ref_from_mem, at alias.c:321
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

[1] http://gcc.gnu.org/ml/gcc-testresults/2009-09/msg02383.html

Uros.