re PR tree-optimization/56837 (-ftree-loop-distribute-patterns generates incorrect code)

2013-04-04  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56837
	* tree-loop-distribution.c (classify_partition): For non-zero
	values require that the value has the same precision as its
	mode to be useful as memset value.

	* g++.dg/torture/pr56837.C: New testcase.

From-SVN: r197476

gcc/ChangeLog

+2013-04-04  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56837
+	* tree-loop-distribution.c (classify_partition): For non-zero
+	values require that the value has the same precision as its
+	mode to be useful as memset value.
+
 2013-04-03  Nick Clifton  <nickc@redhat.com>
 
 	* config/v850/v850e3v5.md (fmasf4): Use fmaf.s on E3V5

gcc/testsuite/ChangeLog

+2013-04-04  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56837
+	* g++.dg/torture/pr56837.C: New testcase.
+
 2013-04-04  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/50269

gcc/testsuite/g++.dg/torture/pr56837.C

+// { dg-do run }
+// { dg-options "-ftree-loop-distribute-patterns" }
+
+extern "C" void abort (void);
+extern "C" int memcmp (const void *, const void *, __SIZE_TYPE__);
+
+bool b1[8];
+bool b2[8] = { true, true, true, true, true, true, true, true };
+
+int main()
+{
+  unsigned int i;
+  for(i=0 ; i < 8; i++)
+    b1[i] = true;
+
+  if (memcmp (b1, b2, 8) != 0)
+    abort ();
+
+  return 0;
+}

gcc/tree-loop-distribution.c

@@ -942,13 +942,17 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
       gimple stmt = DR_STMT (single_store);
       tree rhs = gimple_assign_rhs1 (stmt);
       if (!(integer_zerop (rhs)
-	    || integer_all_onesp (rhs)
 	    || real_zerop (rhs)
 	    || (TREE_CODE (rhs) == CONSTRUCTOR
 		&& !TREE_CLOBBER_P (rhs))
-	    || (INTEGRAL_TYPE_P (TREE_TYPE (rhs))
-		&& (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)))
-		    == TYPE_MODE (unsigned_char_type_node)))))
+	    || ((integer_all_onesp (rhs)
+		 || (INTEGRAL_TYPE_P (TREE_TYPE (rhs))
+		     && (TYPE_MODE (TREE_TYPE (rhs))
+			 == TYPE_MODE (unsigned_char_type_node))))
+		/* For stores of a non-zero value require that the precision
+		   of the value matches its actual size.  */
+		&& (TYPE_PRECISION (TREE_TYPE (rhs))
+		    == GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (rhs)))))))
 	return;
       if (TREE_CODE (rhs) == SSA_NAME
 	  && !SSA_NAME_IS_DEFAULT_DEF (rhs)