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authorAaron Sawdey <acsawdey@linux.vnet.ibm.com>2017-02-13 16:00:22 +0000
committerAaron Sawdey <acsawdey@gcc.gnu.org>2017-02-13 10:00:22 -0600
commit8d6427c6ddefb12bf5656e8938f8055a1201650a (patch)
tree142217a485e81ca4cb3cac2f51a3b9ed1cb7dd8f
parent550e2205cc42e5ca9906c81cbe4c3c4bc285fd5e (diff)
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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
Diffstat
-rw-r--r--gcc/ChangeLog6
-rw-r--r--gcc/config/rs6000/rs6000.c23
-rw-r--r--gcc/testsuite/ChangeLog6
-rw-r--r--gcc/testsuite/gcc.dg/strncmp-2.c99
4 files changed, 128 insertions, 6 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 098b1e6..f352051 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -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.
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 10cbea9..f082479 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -19931,14 +19931,25 @@ expand_strn_compare (rtx operands[], int no_length)
cmpldi cr7,r8,4096-16
bgt cr7,L(pagecross) */
+ /* 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;
+ }
+
if (align1 < 8)
- expand_strncmp_align_check (strncmp_label, src1, compare_length);
+ expand_strncmp_align_check (strncmp_label, src1, align_test);
if (align2 < 8)
- expand_strncmp_align_check (strncmp_label, src2, compare_length);
-
- /* After the runtime alignment checks, we can use any alignment we
- like as we know there is no 4k boundary crossing. */
- base_align = 8;
+ expand_strncmp_align_check (strncmp_label, src2, align_test);
/* Now generate the following sequence:
- branch to begin_compare
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f4497d5..b5e225e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -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
diff --git a/gcc/testsuite/gcc.dg/strncmp-2.c b/gcc/testsuite/gcc.dg/strncmp-2.c
new file mode 100644
index 0000000..0c9a07a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strncmp-2.c
@@ -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;
+}
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