PR rtl-optimization/pr55672

2013-01-10  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/pr55672
	* lra-eliminations.c (mark_not_elimnable): Permit addition with
	const to be elimnable.

2013-01-10  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/pr55672
	* gcc.target/i386/pr55672.c: New.

From-SVN: r195095

gcc/ChangeLog

+2013-01-10  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/pr55672
+	* lra-eliminations.c (mark_not_elimnable): Permit addition with
+	const to be elimnable.
+
 2013-01-10  David Edelsohn  <dje.gcc@gmail.com>
 
 	* configure.ac (HAVE_AS_TLS): Add check for powerpc-ibm-aix.

gcc/lra-eliminations.c

@@ -657,7 +657,7 @@ mark_not_eliminable (rtx x)
     case PRE_MODIFY:
       if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER)
 	/* If we modify the source of an elimination rule, disable
-	   it. Do the same if it is the source and not the hard frame
+	   it.  Do the same if it is the source and not the hard frame
 	   register.  */
 	for (ep = reg_eliminate;
 	     ep < &reg_eliminate[NUM_ELIMINABLE_REGS];
@@ -716,7 +716,10 @@ mark_not_eliminable (rtx x)
 	       ep < &reg_eliminate[NUM_ELIMINABLE_REGS];
 	       ep++)
 	    if (ep->to_rtx == SET_DEST (x)
-		&& SET_DEST (x) != hard_frame_pointer_rtx)
+		&& SET_DEST (x) != hard_frame_pointer_rtx
+		&& (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

+2013-01-10  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/pr55672
+	* gcc.target/i386/pr55672.c: New.
+
 2013-01-10  Jeff Law  <law@redhat.com>
 
 	* gcc/dg/tree-ssa/vrp06.c: Tighten expected output.  Make each

gcc/testsuite/gcc.target/i386/pr55672.c

+/* { dg-do compile } */
+/* { dg-options "-O -fstack-check=generic" } */
+
+int main ()
+{
+  int x[8];
+  if (x[0] != 4)
+    __builtin_abort ();
+  return 0;
+}