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x86-64: Use notl in EVEX strcmp [BZ #28646]

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Must use notl %edi here as lower bits are for CHAR comparisons
potentially out of range thus can be 0 without indicating mismatch.
This fixes BZ #28646.

Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
Noah Goldstein 2021-12-03 15:29:25 -08:00 committed by H.J. Lu
parent 23c77f6018
commit 4df1fa6ddc
2 changed files with 36 additions and 6 deletions
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28
string/test-strcmp.c
View File

@ -23,6 +23,7 @@
# define TEST_NAME "strcmp"
#endif
#include "test-string.h"
#include <support/test-driver.h>
#ifdef WIDE
# include <wchar.h>
@ -390,6 +391,32 @@ check2 (void)
}
}
static void
check3 (void)
{
size_t size = 0xd000 + 0x4000;
CHAR *s1, *s2;
CHAR *buffer1 = mmap (NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON, -1, 0);
CHAR *buffer2 = mmap (NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON, -1, 0);
if (buffer1 == MAP_FAILED || buffer1 == MAP_FAILED)
error (EXIT_UNSUPPORTED, errno, "mmap failed");
s1 = (CHAR *) (buffer1 + 0x8f8 / sizeof (CHAR));
s2 = (CHAR *) (buffer2 + 0xcff3 / sizeof (CHAR));
STRCPY(s1, L("/export/redhat/rpms/BUILD/java-1.8.0-openjdk-1.8.0.312.b07-2.fc35.x86_64/openjdk/langtools/src/share/classes/com/sun/tools/doclets/internal/toolkit/util/PathDocFileFactory.java"));
STRCPY(s2, L("/export/redhat/rpms/BUILD/java-1.8.0-openjdk-1.8.0.312.b07-2.fc35.x86_64/openjdk/langtools/src/share/classes/com/sun/tools/doclets/internal/toolkit/taglets/ThrowsTaglet.java"));
int exp_result = SIMPLE_STRCMP (s1, s2);
FOR_EACH_IMPL (impl, 0)
check_result (impl, s1, s2, exp_result);
munmap ((void *) buffer1, size);
munmap ((void *) buffer2, size);
}
int
test_main (void)
{
@ -398,6 +425,7 @@ test_main (void)
test_init ();
check();
check2 ();
check3 ();
printf ("%23s", "");
FOR_EACH_IMPL (impl, 0)

14
sysdeps/x86_64/multiarch/strcmp-evex.S
View File

@ -646,12 +646,13 @@ L(loop_cross_page):
in YMM3 and 32 bytes at VEC_SIZE(%rdx, %r10). */
VPCMP $0, VEC_SIZE(%rdx, %r10), %YMM3, %k3{%k4}
kmovd %k3, %edi
/* Must use notl %edi here as lower bits are for CHAR
comparisons potentially out of range thus can be 0 without
indicating mismatch. */
notl %edi
# ifdef USE_AS_WCSCMP
/* Don't use subl since it is the upper 8 bits of EDI below. */
notl %edi
andl $0xff, %edi
# else
incl %edi
# endif
# ifdef USE_AS_WCSCMP
@ -733,12 +734,13 @@ L(loop_cross_page_2_vec):
in YMM1 and 32 bytes at (VEC_SIZE * 3)(%rdx, %r10). */
VPCMP $0, (VEC_SIZE * 3)(%rdx, %r10), %YMM1, %k3{%k4}
kmovd %k3, %edi
/* Must use notl %edi here as lower bits are for CHAR
comparisons potentially out of range thus can be 0 without
indicating mismatch. */
notl %edi
# ifdef USE_AS_WCSCMP
/* Don't use subl since it is the upper 8 bits of EDI below. */
notl %edi
andl $0xff, %edi
# else
incl %edi
# endif
# ifdef USE_AS_WCSCMP