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re PR rtl-optimization/79032 (unaligned memory access generated with LRA and optimization)

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PR rtl-optimization/79032
	* lra-constraints.c (simplify_operand_subreg): In the MEM case, test
	the alignment of the adjusted memory reference against that of MODE,
	instead of the alignment of the original memory reference.

From-SVN: r244311
This commit is contained in:
Eric Botcazou 2017-01-11 11:27:43 +00:00 committed by Eric Botcazou
parent e325277522
commit 849fccf831
4 changed files with 48 additions and 4 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2017-01-11 Eric Botcazou <ebotcazou@adacore.com>
PR rtl-optimization/79032
* lra-constraints.c (simplify_operand_subreg): In the MEM case, test
the alignment of the adjusted memory reference against that of MODE,
instead of the alignment of the original memory reference.
2017-01-11 Martin Jambor <mjambor@suse.cz>
* hsa.c (hsa_callable_function_p): Revert addition of DECL_ARTIFICIAL

8
gcc/lra-constraints.c
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@ -1505,15 +1505,15 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
MEM_ADDR_SPACE (subst))))
{
/* If we change the address for a paradoxical subreg of memory, the
address might violate the necessary alignment or the access might
be slow. So take this into consideration. We need not worry
new address might violate the necessary alignment or the access
might be slow; take this into consideration. We need not worry
about accesses beyond allocated memory for paradoxical memory
subregs as we don't substitute such equiv memory (see processing
equivalences in function lra_constraints) and because for spilled
pseudos we allocate stack memory enough for the biggest
corresponding paradoxical subreg. */
if (!(MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (mode)
&& SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (reg)))
if (!(MEM_ALIGN (subst) < GET_MODE_ALIGNMENT (mode)
&& SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (subst)))
|| (MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (innermode)
&& SLOW_UNALIGNED_ACCESS (innermode, MEM_ALIGN (reg))))
return true;

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2017-01-11 Eric Botcazou <ebotcazou@adacore.com>
* gcc.c-torture/execute/20170111-1.c: New test.
2017-01-11 Richard Biener <rguenther@suse.de>
* gcc.dg/tree-ssa/pr61743-1.c: Adjust.

33
gcc/testsuite/gcc.c-torture/execute/20170111-1.c Normal file
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@ -0,0 +1,33 @@
/* PR rtl-optimization/79032 */
/* Reported by Daniel Cederman <cederman@gaisler.com> */
extern void abort (void);
struct S {
short a;
long long b;
short c;
char d;
unsigned short e;
long *f;
};
static long foo (struct S *s) __attribute__((noclone, noinline));
static long foo (struct S *s)
{
long a = 1;
a /= s->e;
s->f[a]--;
return a;
}
int main (void)
{
long val = 1;
struct S s = { 0, 0, 0, 0, 2, &val };
val = foo (&s);
if (val != 0)
abort ();
return 0;
}