[PATCH AArch64]: Add constraint letter for stack_protect_test pattern

gcc/

	* config/aarch64/aarch64.md (stack_protect_test_<mode>): Mark
	scratch register as an output to placate register renaming.

gcc/testsuite/

	* gcc.dg/ssp-3.c: New.
	* gcc.dg/ssp-4.c: Likewise.

From-SVN: r215385

gcc/ChangeLog

+2014-09-19  James Greenhalgh  <james.greenhalgh@arm.com>
+
+	* config/aarch64/aarch64.md (stack_protect_test_<mode>): Mark
+	scratch register as written.
+
 2014-09-19  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
 
 	* config/s390/s390.c (s390_emit_epilogue): Remove bogus

gcc/config/aarch64/aarch64.md

@@ -4031,7 +4031,7 @@
 	(unspec:PTR [(match_operand:PTR 1 "memory_operand" "m")
 		     (match_operand:PTR 2 "memory_operand" "m")]
 	 UNSPEC_SP_TEST))
-   (clobber (match_scratch:PTR 3 "&r"))]
+   (clobber (match_scratch:PTR 3 "=&r"))]
   ""
   "ldr\t%<w>3, %x1\;ldr\t%<w>0, %x2\;eor\t%<w>0, %<w>3, %<w>0"
   [(set_attr "length" "12")

gcc/testsuite/ChangeLog

+2014-09-19  James Greenhalgh  <james.greenhalgh@arm.com>
+
+	* gcc.dg/ssp-3.c: New.
+	* gcc.dg/ssp-4.c: Likewise.
+
 2014-09-19  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>
 
 	* gcc.target/s390/dfp-conv1.c: New testcase.

gcc/testsuite/gcc.dg/ssp-3.c

+/* { dg-do assemble } */
+/* { dg-options "-fstack-protector-strong -O1 -frename-registers" } */
+/* { dg-require-effective-target fstack_protector } */
+
+extern int bar (const char *s, int *argc);
+extern int baz (const char *s);
+
+char
+foo (const char *s)
+{
+  int argc;
+  int ret;
+  if ( !bar (s, &argc))
+    ret = baz (s);
+  return *s;
+}

gcc/testsuite/gcc.dg/ssp-4.c

+/* { dg-do assemble } */
+/* { dg-options "-fstack-protector-strong -O1 -frename-registers" } */
+/* { dg-require-effective-target fstack_protector } */
+
+typedef unsigned int uint32_t;
+struct ctx
+{
+  uint32_t A;
+};
+
+void *
+buffer_copy (const struct ctx *ctx, void *resbuf)
+{
+  uint32_t buffer[4];
+  buffer[0] = (ctx->A);
+  __builtin_memcpy (resbuf, buffer, sizeof (buffer));
+  return resbuf;
+}