Let tree_single_nonzero_warnv_p use range information

2017-04-25  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* fold-const.c (tree_single_nonzero_warnv_p): Handle SSA_NAME.

gcc/testsuite/
	* gcc.dg/tree-ssa/cmpmul-1.c: New file.
	* gcc.dg/Wstrict-overflow-18.c: Xfail.

From-SVN: r247123

gcc/ChangeLog

+2017-04-25  Marc Glisse  <marc.glisse@inria.fr>
+
+	* fold-const.c (tree_single_nonzero_warnv_p): Handle SSA_NAME.
+
 2017-04-25  Julian Brown  <julian@codesourcery.com>
 	    Naveen H.S  <Naveen.Hurugalawadi@cavium.com>
 

gcc/fold-const.c

@@ -13412,6 +13412,11 @@ tree_single_nonzero_warnv_p (tree t, bool *strict_overflow_p)
 	}
       break;
 
+    case SSA_NAME:
+      if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
+	break;
+      return expr_not_equal_to (t, wi::zero (TYPE_PRECISION (TREE_TYPE (t))));
+
     default:
       break;
     }

gcc/testsuite/ChangeLog

+2017-04-25  Marc Glisse  <marc.glisse@inria.fr>
+
+	* gcc.dg/tree-ssa/cmpmul-1.c: New file.
+	* gcc.dg/Wstrict-overflow-18.c: Xfail.
+
 2017-04-22  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/80121

gcc/testsuite/gcc.dg/Wstrict-overflow-18.c

@@ -14,7 +14,8 @@ foo (struct c *p)
 
   for (i = 0; i < p->a - p->b; ++i)
     {
-      if (i > 0)  /* { dg-warning "signed overflow" "" } */
+      /* See PR80511 for the XFAIL.  */
+      if (i > 0)  /* { dg-warning "signed overflow" "" { xfail *-*-* } } */
 	sum += 2;
       bar (p);
     }

gcc/testsuite/gcc.dg/tree-ssa/cmpmul-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+
+int f(int a, int b, int c){
+  c |= 1; // c cannot be 0
+  a *= c;
+  b *= c;
+  return a == b;
+}
+
+/* { dg-final { scan-tree-dump-not "bit_ior_expr" "optimized" } } */