> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
>
> Richard.
>
> 2017-03-28 Richard Biener <rguent...@suse.de>
>
> PR middle-end/80222
> * gimple-fold.c (gimple_fold_indirect_ref): Do not touch
> TYPE_REF_CAN_ALIAS_ALL references.
> * fold-const.c (fold_indirect_ref_1): Likewise.
You just backported it onto the 6 branch and the fold_indirect_ref_1 hunk
alone introduced regressions in the C testsuite on the branch for strict-
alignment architectures, e.g. SPARC. Reduced testcase:
typedef long long V
__attribute__ ((vector_size (2 * sizeof (long long)), may_alias));
typedef struct S { V b; } P __attribute__((aligned (1)));
__attribute__((noinline, noclone)) void
bar (P *p)
{
p->b[1] = 5;
}
Before the patch at -O0:
bar:
save %sp, -96, %sp
st %i0, [%fp+68]
ld [%fp+68], %g1
ldub [%g1+12], %g2
and %g2, 0, %g2
stb %g2, [%g1+12]
ldub [%g1+13], %g2
and %g2, 0, %g2
stb %g2, [%g1+13]
ldub [%g1+14], %g2
and %g2, 0, %g2
stb %g2, [%g1+14]
ldub [%g1+15], %g2
and %g2, 0, %g2
or %g2, 5, %g2
stb %g2, [%g1+15]
ldub [%g1+8], %g2
and %g2, 0, %g2
stb %g2, [%g1+8]
ldub [%g1+9], %g2
and %g2, 0, %g2
stb %g2, [%g1+9]
ldub [%g1+10], %g2
and %g2, 0, %g2
stb %g2, [%g1+10]
ldub [%g1+11], %g2
and %g2, 0, %g2
stb %g2, [%g1+11]
nop
return %i7+8
nop
After the patch:
bar:
save %sp, -96, %sp
st %i0, [%fp+68]
ld [%fp+68], %g1
add %g1, 8, %g1
mov 0, %g2
mov 5, %g3
std %g2, [%g1]
nop
return %i7+8
nop
that is to say, the compiler now generates an unaligned store.
--
Eric Botcazou
