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re PR tree-optimization/79824 (Failure to peel for gaps leads to read beyond mapped memory) 

2017-03-06  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79824
	* tree-vect-stmts.c (get_group_load_store_type): Fix alignment
	check disabling peeling for gaps.

	* gcc.dg/vect/pr79824-1.c: New testcase.
	* gcc.dg/vect/pr79824-2.c: Likewise.

From-SVN: r245922
This commit is contained in:
Richard Biener 2017-03-06 13:58:01 +00:00 committed by Richard Biener
parent 5464963112
commit 522fcdd739
5 changed files with 113 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2017-03-06 Richard Biener <rguenther@suse.de>
PR tree-optimization/79824
* tree-vect-stmts.c (get_group_load_store_type): Fix alignment
check disabling peeling for gaps.
2017-03-06 Toma Tabacu <toma.tabacu@imgtec.com>
* doc/sourcebuild.texi (Effective-Target Keywords, Environment

6
gcc/testsuite/ChangeLog
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@ -1,3 +1,9 @@
2017-03-06 Richard Biener <rguenther@suse.de>
PR tree-optimization/79824
* gcc.dg/vect/pr79824-1.c: New testcase.
* gcc.dg/vect/pr79824-2.c: Likewise.
2017-03-06 Toma Tabacu <toma.tabacu@imgtec.com>
* gcc.dg/lto/pr60449_0.c: Add dg-require-effective-target for

46
gcc/testsuite/gcc.dg/vect/pr79824-1.c Normal file
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@ -0,0 +1,46 @@
/* { dg-require-effective-target mmap } */
#include <sys/mman.h>
#include <stdio.h>
#include "tree-vect.h"
#define COUNT 320
#define MMAP_SIZE 0x10000
#define ADDRESS 0x1122000000
#define TYPE double
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
void __attribute__((noinline))
foo (TYPE *__restrict a, TYPE *__restrict b)
{
int n;
b = __builtin_assume_aligned (b, sizeof (TYPE) * 2);
a = __builtin_assume_aligned (a, sizeof (TYPE) * 2);
for (n = 0; n < COUNT; n++)
a[n] = b[n * 4];
}
int
main (void)
{
void *x;
size_t b_offset;
check_vect ();
x = mmap ((void *) ADDRESS, MMAP_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (x == MAP_FAILED)
{
perror ("mmap");
return 1;
}
b_offset = MMAP_SIZE - (4 * COUNT - 2) * sizeof (TYPE);
foo ((TYPE *) x, (TYPE *) ((char *) x + b_offset));
return 0;
}

48
gcc/testsuite/gcc.dg/vect/pr79824-2.c Normal file
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@ -0,0 +1,48 @@
/* { dg-require-effective-target mmap } */
#include <sys/mman.h>
#include <stdio.h>
#include "tree-vect.h"
#define COUNT 320
#define MMAP_SIZE 0x10000
#define ADDRESS 0x1122000000
#define TYPE double
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
void __attribute__((noinline))
foo (TYPE *__restrict a, TYPE *__restrict b)
{
int n;
b = __builtin_assume_aligned (b, sizeof (TYPE) * 2);
a = __builtin_assume_aligned (a, sizeof (TYPE) * 2);
for (n = 0; n < COUNT; n++)
{
a[n] = b[n * 4] + b[n * 4 + 1];
}
}
int
main (void)
{
void *x;
size_t b_offset;
check_vect ();
x = mmap ((void *) ADDRESS, MMAP_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (x == MAP_FAILED)
{
perror ("mmap");
return 1;
}
b_offset = MMAP_SIZE - (4 * COUNT - 2) * sizeof (TYPE);
foo ((TYPE *) x, (TYPE *) ((char *) x + b_offset));
return 0;
}

10
gcc/tree-vect-stmts.c
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@ -1731,7 +1731,7 @@ get_group_load_store_type (gimple *stmt, tree vectype, bool slp,
bool single_element_p = (stmt == first_stmt
&& !GROUP_NEXT_ELEMENT (stmt_info));
unsigned HOST_WIDE_INT gap = GROUP_GAP (vinfo_for_stmt (first_stmt));
int nunits = TYPE_VECTOR_SUBPARTS (vectype);
unsigned nunits = TYPE_VECTOR_SUBPARTS (vectype);
/* True if the vectorized statements would access beyond the last
statement in the group. */
@ -1794,9 +1794,13 @@ get_group_load_store_type (gimple *stmt, tree vectype, bool slp,
/* If there is a gap at the end of the group then these optimizations
would access excess elements in the last iteration. */
bool would_overrun_p = (gap != 0);
/* If the access is aligned an overrun is fine. */
/* If the access is aligned an overrun is fine, but only if the
overrun is not inside an unused vector (if the gap is as large
or larger than a vector). */
if (would_overrun_p
&& aligned_access_p (STMT_VINFO_DATA_REF (stmt_info)))
&& gap < nunits
&& aligned_access_p
(STMT_VINFO_DATA_REF (vinfo_for_stmt (first_stmt))))
would_overrun_p = false;
if (!STMT_VINFO_STRIDED_P (stmt_info)
&& (can_overrun_p || !would_overrun_p)