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re PR target/79449 (ppc builtin expansion of strncmp can cross page (4k) boundary where it should not) 

2017-02-13  Aaron Sawdey  <acsawdey@linux.vnet.ibm.com>

	PR target/79449
	* gcc.dg/strncmp-2.c: New.  Test strncmp and memcmp builtin expansion
	for reading beyond a 4k boundary.

2017-02-13  Aaron Sawdey  <acsawdey@linux.vnet.ibm.com>

	PR target/79449
	* config/rs6000/rs6000.c (expand_block_compare): Make sure runtime
	boundary crossing check and subsequent code generation agree.

From-SVN: r245392
This commit is contained in:
Aaron Sawdey 2017-02-13 16:00:22 +00:00 committed by Aaron Sawdey
parent 550e2205cc
commit 8d6427c6dd
4 changed files with 129 additions and 7 deletions
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6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2017-02-13 Aaron Sawdey <acsawdey@linux.vnet.ibm.com>
PR target/79449
* config/rs6000/rs6000.c (expand_block_compare): Make sure runtime
boundary crossing check and subsequent code generation agree.
2017-02-13 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
* config/aarch64/aarch64.c (has_memory_op): Delete.

25
gcc/config/rs6000/rs6000.c
View File

@ -19931,14 +19931,25 @@ expand_strn_compare (rtx operands[], int no_length)
cmpldi cr7,r8,4096-16
bgt cr7,L(pagecross) */
if (align1 < 8)
expand_strncmp_align_check (strncmp_label, src1, compare_length);
if (align2 < 8)
expand_strncmp_align_check (strncmp_label, src2, compare_length);
/* Make sure that the length we use for the alignment test and
the subsequent code generation are in agreement so we do not
go past the length we tested for a 4k boundary crossing. */
unsigned HOST_WIDE_INT align_test = compare_length;
if (align_test < 8)
{
align_test = HOST_WIDE_INT_1U << ceil_log2 (align_test);
base_align = align_test;
}
else
{
align_test = ROUND_UP (align_test, 8);
base_align = 8;
}
/* After the runtime alignment checks, we can use any alignment we
like as we know there is no 4k boundary crossing. */
base_align = 8;
if (align1 < 8)
expand_strncmp_align_check (strncmp_label, src1, align_test);
if (align2 < 8)
expand_strncmp_align_check (strncmp_label, src2, align_test);
/* Now generate the following sequence:
- branch to begin_compare

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2017-02-13 Aaron Sawdey <acsawdey@linux.vnet.ibm.com>
PR target/79449
* gcc.dg/strncmp-2.c: New. Test strncmp and memcmp builtin expansion
for reading beyond a 4k boundary.
2017-02-13 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/79388

99
gcc/testsuite/gcc.dg/strncmp-2.c Normal file
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@ -0,0 +1,99 @@
/* Test strncmp builtin expansion for compilation and proper execution. */
/* { dg-do run { target *-*-linux* *-*-gnu* } } */
/* { dg-options "-O2" } */
/* { dg-require-effective-target ptr32plus } */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <stdlib.h>
int lib_memcmp(const void *a, const void *b, size_t n) asm("memcmp");
int lib_strncmp(const char *a, const char *b, size_t n) asm("strncmp");
static void test_driver_strncmp (void (test_strncmp)(const char *, const char *, int),
void (test_memcmp)(const void *, const void *, int),
size_t sz)
{
long pgsz = sysconf(_SC_PAGESIZE);
char buf1[sz+1];
char *buf2 = aligned_alloc(pgsz,2*pgsz);
char *p2;
int r,i,e;
r = mprotect (buf2+pgsz,pgsz,PROT_NONE);
if (r < 0) abort();
memset(buf1,'A',sz);
for(i=10; i>=0; i--) {
p2 = buf2+pgsz-sz-i;
memset(p2,'A',sz);
e = lib_strncmp(buf1,p2,sz);
(*test_strncmp)(buf1,p2,e);
e = lib_memcmp(buf1,p2,sz);
(*test_memcmp)(buf1,p2,e);
}
}
#define RUN_TEST(SZ) test_driver_strncmp (test_strncmp_ ## SZ, test_memcmp_ ## SZ, SZ);
#define DEF_TEST(SZ) \
__attribute__((noinline)) \
void test_strncmp_ ## SZ (const char *str1, const char *str2, int expect) \
{ \
int r; \
r = strncmp(str1,str2,SZ); \
if ( r < 0 && !(expect < 0) ) abort(); \
if ( r > 0 && !(expect > 0) ) abort(); \
if ( r == 0 && !(expect == 0) ) abort(); \
} \
__attribute__((noinline)) \
void test_memcmp_ ## SZ (const void *p1, const void *p2, int expect) \
{ \
int r; \
r = memcmp(p1,p2,SZ); \
if ( r < 0 && !(expect < 0) ) abort(); \
if ( r > 0 && !(expect > 0) ) abort(); \
if ( r == 0 && !(expect == 0) ) abort(); \
}
DEF_TEST(1)
DEF_TEST(2)
DEF_TEST(3)
DEF_TEST(4)
DEF_TEST(5)
DEF_TEST(6)
DEF_TEST(7)
DEF_TEST(8)
DEF_TEST(9)
DEF_TEST(10)
DEF_TEST(11)
DEF_TEST(12)
DEF_TEST(13)
DEF_TEST(14)
DEF_TEST(15)
DEF_TEST(16)
int
main(int argc, char **argv)
{
RUN_TEST(1) ;
RUN_TEST(2) ;
RUN_TEST(3) ;
RUN_TEST(4) ;
RUN_TEST(5) ;
RUN_TEST(6) ;
RUN_TEST(7) ;
RUN_TEST(8) ;
RUN_TEST(9) ;
RUN_TEST(10);
RUN_TEST(11);
RUN_TEST(12);
RUN_TEST(13);
RUN_TEST(14);
RUN_TEST(15);
RUN_TEST(16);
return 0;
}