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re PR rtl-optimization/55547 (Alias analysis does not handle AND addresses correctly) 

PR rtl-optimization/55547
PR rtl-optimization/53827
PR debug/53671
PR debug/49888
* alias.c (memrefs_conflict_p): Set sizes to negative after
AND adjustments.

From-SVN: r195227
This commit is contained in:
Alexandre Oliva 2013-01-16 04:31:30 +00:00 committed by Alexandre Oliva
parent c851c76cdf
commit 5147bf6a23
2 changed files with 22 additions and 5 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2013-01-16 Alexandre Oliva <aoliva@redhat.com>
PR rtl-optimization/55547
PR rtl-optimization/53827
PR debug/53671
PR debug/49888
* alias.c (memrefs_conflict_p): Set sizes to negative after
AND adjustments.
2013-01-15 Jakub Jelinek <jakub@redhat.com>
PR target/55940

18
gcc/alias.c
View File

@ -2080,14 +2080,20 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
/* Deal with alignment ANDs by adjusting offset and size so as to
cover the maximum range, without taking any previously known
alignment into account. */
alignment into account. Make a size negative after such an
adjustments, so that, if we end up with e.g. two SYMBOL_REFs, we
assume a potential overlap, because they may end up in contiguous
memory locations and the stricter-alignment access may span over
part of both. */
if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
{
HOST_WIDE_INT sc = INTVAL (XEXP (x, 1));
unsigned HOST_WIDE_INT uc = sc;
if (xsize > 0 && sc < 0 && -uc == (uc & -uc))
if (sc < 0 && -uc == (uc & -uc))
{
xsize -= sc + 1;
if (xsize > 0)
xsize = -xsize;
xsize += sc + 1;
c -= sc + 1;
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
ysize, y, c);
@ -2097,9 +2103,11 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
{
HOST_WIDE_INT sc = INTVAL (XEXP (y, 1));
unsigned HOST_WIDE_INT uc = sc;
if (ysize > 0 && sc < 0 && -uc == (uc & -uc))
if (sc < 0 && -uc == (uc & -uc))
{
ysize -= sc + 1;
if (ysize > 0)
ysize = -ysize;
ysize += sc + 1;
c += sc + 1;
return memrefs_conflict_p (xsize, x,
ysize, canon_rtx (XEXP (y, 0)), c);