re PR middle-end/36988 (ICE in gimple_rhs_has_side_effects, at gimple.c:2369)

2008-08-01  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/36988
	* tree-ssa-ccp.c (ccp_fold): Conversions of constants only
	do not matter if that doesn't change volatile qualification.

	* gcc.c-torture/compile/pr36988.c: New testcase.

From-SVN: r138512

gcc/ChangeLog

+2008-08-01  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/36988
+	* tree-ssa-ccp.c (ccp_fold): Conversions of constants only
+	do not matter if that doesn't change volatile qualification.
+
 2008-08-01  Paolo Bonzini  <bonzini@gnu.org>
 
 	* configure.ac: Do not generate libada-mk.  Do not subst

gcc/testsuite/ChangeLog

+2008-08-01  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/36988
+	* gcc.c-torture/compile/pr36988.c: New testcase.
+
 2008-08-01  Olivier Hainque  <hainque@adacore.com>
 
 	* gnat.dg/raise_from_pure.ad[bs],

gcc/testsuite/gcc.c-torture/compile/pr36988.c

+typedef struct {
+    unsigned char mbxCommand;
+} MAILBOX_t;
+void lpfc_sli_brdrestart(void)
+{
+  volatile unsigned int word0;
+  MAILBOX_t *mb;
+  mb = (MAILBOX_t *) &word0;
+  mb->mbxCommand = 0x1A;
+  __writel((*(unsigned int *) mb));
+}

gcc/tree-ssa-ccp.c

@@ -989,7 +989,13 @@ ccp_fold (gimple stmt)
 		 allowed places.  */
               if ((subcode == NOP_EXPR || subcode == CONVERT_EXPR)
 		  && ((POINTER_TYPE_P (TREE_TYPE (lhs))
-		       && POINTER_TYPE_P (TREE_TYPE (op0)))
+		       && POINTER_TYPE_P (TREE_TYPE (op0))
+		       /* Do not allow differences in volatile qualification
+			  as this might get us confused as to whether a
+			  propagation destination statement is volatile
+			  or not.  See PR36988.  */
+		       && (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (lhs)))
+			   == TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (op0)))))
 		      || useless_type_conversion_p (TREE_TYPE (lhs),
 						    TREE_TYPE (op0))))
                 return op0;