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tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of the variable part of the offset as well. 

* tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of
	the variable part of the offset as well.  Use highest_pow2_factor for
	all alignment checks.

From-SVN: r158951
This commit is contained in:
Eric Botcazou 2010-04-30 21:22:53 +00:00
parent 881139c3ef
commit 25a367c855
4 changed files with 71 additions and 8 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2010-04-30 Eric Botcazou <ebotcazou@adacore.com>
* tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of
the variable part of the offset as well. Use highest_pow2_factor for
all alignment checks.
2010-04-30 Jakub Jelinek <jakub@redhat.com>
PR c/43893

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2010-04-30 DJ Delorie <dj@redhat.com>
* gcc.c-torture/execute/20100430-1.c: New test.
2010-04-29 Release Manager
* GCC 4.4.4 released.

51
gcc/testsuite/gcc.c-torture/execute/20100430-1.c Normal file
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@ -0,0 +1,51 @@
/* This used to generate unaligned accesses at -O2 because of IVOPTS. */
struct packed_struct
{
struct packed_struct1
{
unsigned char cc11;
unsigned char cc12;
} __attribute__ ((packed)) pst1;
struct packed_struct2
{
unsigned char cc21;
unsigned char cc22;
unsigned short ss[104];
unsigned char cc23[13];
} __attribute__ ((packed)) pst2[4];
} __attribute__ ((packed));
typedef struct
{
int ii;
struct packed_struct buf;
} info_t;
static unsigned short g;
static void __attribute__((noinline))
dummy (unsigned short s)
{
g = s;
}
static int
foo (info_t *info)
{
int i, j;
for (i = 0; i < info->buf.pst1.cc11; i++)
for (j = 0; j < info->buf.pst2[i].cc22; j++)
dummy (info->buf.pst2[i].ss[j]);
return 0;
}
int main(void)
{
info_t info;
info.buf.pst1.cc11 = 2;
info.buf.pst2[0].cc22 = info.buf.pst2[1].cc22 = 8;
return foo (&info);
}

18
gcc/tree-ssa-loop-ivopts.c
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@ -1525,16 +1525,18 @@ may_be_unaligned_p (tree ref, tree step)
if (mode != BLKmode)
{
double_int mul;
tree al = build_int_cst (TREE_TYPE (step),
GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT);
unsigned mode_align = GET_MODE_ALIGNMENT (mode);
if (base_align < GET_MODE_ALIGNMENT (mode)
|| bitpos % GET_MODE_ALIGNMENT (mode) != 0
|| bitpos % BITS_PER_UNIT != 0)
if (base_align < mode_align
|| (bitpos % mode_align) != 0
|| (bitpos % BITS_PER_UNIT) != 0)
return true;
if (!constant_multiple_of (step, al, &mul))
if (toffset
&& (highest_pow2_factor (toffset) * BITS_PER_UNIT) < mode_align)
return true;
if ((highest_pow2_factor (step) * BITS_PER_UNIT) < mode_align)
return true;
}