re PR target/57018 (Miscompilation of bison 2.7.1 under "-Os -fomit-frame-pointer")

2013-04-22  Vladimir Makarov  <vmakarov@redhat.com>

	PR target/57018
	* lra-eliminations.c (mark_not_eliminable): Prevent elimination of
	a set sp if no stack realignment.

2013-04-22  Vladimir Makarov  <vmakarov@redhat.com>

	PR target/57018
	* gcc.target/i386/pr57018.c: New test.

From-SVN: r198140

gcc/ChangeLog

+2013-04-22  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR target/57018
+	* lra-eliminations.c (mark_not_eliminable): Prevent elimination of
+	a set sp if no stack realignment.
+
 2013-04-22  Nick Clifton  <nickc@redhat.com>
 
 	* config.gcc (tilegx-linux): Extend extra_objs rather than

gcc/lra-eliminations.c

@@ -716,7 +716,9 @@ mark_not_eliminable (rtx x)
 	       ep++)
 	    if (ep->to_rtx == SET_DEST (x)
 		&& SET_DEST (x) != hard_frame_pointer_rtx
-		&& (GET_CODE (SET_SRC (x)) != PLUS
+		&& (! (SUPPORTS_STACK_ALIGNMENT && stack_realign_fp
+		       && REGNO (ep->to_rtx) == STACK_POINTER_REGNUM)
+		    || GET_CODE (SET_SRC (x)) != PLUS
 		    || XEXP (SET_SRC (x), 0) != SET_DEST (x)
 		    || ! CONST_INT_P (XEXP (SET_SRC (x), 1))))
 	      setup_can_eliminate (ep, false);

gcc/testsuite/ChangeLog

+2013-04-22  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR target/57018
+	* gcc.target/i386/pr57018.c: New test.
+
 2013-04-22  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* gcc.target/aarch64/vrecps.c: New.

gcc/testsuite/gcc.target/i386/pr57018.c

+/* { dg-do run } */
+/* { dg-options "-Os -fomit-frame-pointer -fno-asynchronous-unwind-tables" } */
+/* { dg-additional-options "-march=i686" { target ia32 } } */
+
+struct A { char a[16]; } a;
+
+void __attribute__((noinline, noclone))
+foo (struct A b)
+{
+  if (__builtin_memcmp (b.a, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16))
+    __builtin_abort ();
+  asm volatile ("" : : : "memory");
+}
+
+void __attribute__((noinline, noclone))
+bar (struct A b)
+{
+  foo (a);
+  a = b;
+}
+
+int
+main ()
+{
+  struct A b = { "\0\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17" };
+  bar (b);
+  if (__builtin_memcmp (a.a, b.a, 16))
+    __builtin_abort ();
+  return 0;
+}
+