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optabs.c (expand_atomic_load): Do not assume compare_and_swap will succeed for larger than word integers.

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* optabs.c (expand_atomic_load): Do not assume compare_and_swap will
	succeed for larger than word integers.

From-SVN: r184009
This commit is contained in:
Andrew MacLeod 2012-02-08 15:26:02 +00:00 • committed by Andrew Macleod
parent ea72cc1dca
commit c51ec0a3d6
2 changed files with 11 additions and 3 deletions
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gcc/ChangeLog
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@ -1,3 +1,8 @@
2012-02-08 Andrew MacLeod <amacleod@redhat.com>
* optabs.c (expand_atomic_load): Do not assume compare_and_swap will
always succeed for integers larger than a native word.
2012-02-08 Richard Guenther <rguenther@suse.de>
PR rtl-optimization/52170

9
gcc/optabs.c
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@ -7665,9 +7665,12 @@ expand_atomic_load (rtx target, rtx mem, enum memmodel model)
/* Issue val = compare_and_swap (mem, 0, 0).
This may cause the occasional harmless store of 0 when the value is
already 0, but it seems to be OK according to the standards guys. */
expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
const0_rtx, false, model, model);
return target;
if (expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
const0_rtx, false, model, model))
return target;
else
/* Otherwise there is no atomic load, leave the library call. */
return NULL_RTX;
}
/* Otherwise assume loads are atomic, and emit the proper barriers. */