re PR tree-optimization/64130 (vrp: handle non zero constant divided by range cannot be zero.)

gcc/ChangeLog:

2015-06-29  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/64130
	* tree-vrp.c (extract_range_from_binary_expr_1): For unsigned
	division, compute max and min when value ranges for dividend and
	divisor are available.


gcc/testsuite/ChangeLog:

2015-06-29  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/64130
	* gcc.dg/tree-ssa/pr64130.c: New test.

From-SVN: r225108

gcc/ChangeLog

+2015-06-29  Kugan Vivekanandarajah  <kuganv@linaro.org>
+
+	PR middle-end/64130
+	* tree-vrp.c (extract_range_from_binary_expr_1): For unsigned
+	division, compute max and min when value ranges for dividend and
+	divisor are available.
+
 2015-06-28  Chung-Lin Tang <cltang@codesourcery.com>
 	    Sandra Loosemore <sandra@codesourcery.com>
 

gcc/testsuite/ChangeLog

+2015-06-29  Kugan Vivekanandarajah  <kuganv@linaro.org>
+
+	PR middle-end/64130
+	* gcc.dg/tree-ssa/pr64130.c: New test.
+
 2015-06-26  Jiong Wang  <jiong.wang@arm.com>
 
 	* gcc.target/aarch64/pic-small.c: New testcase.

gcc/testsuite/gcc.dg/tree-ssa/pr64130.c

+
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+
+int funsigned (unsigned a)
+{
+  return 0x1ffffffffL / a == 0;
+}
+
+int funsigned2 (unsigned a)
+{
+  if (a < 1) return 1;
+  return (-1 * 0x1ffffffffL) / a == 0;
+}
+
+/* { dg-final { scan-tree-dump ": \\\[2, 8589934591\\\]" "vrp1" } } */
+/* { dg-final { scan-tree-dump ": \\\[-8589934591, -2\\\]" "vrp1" } } */
+

gcc/tree-vrp.c

@@ -3133,14 +3133,33 @@ extract_range_from_binary_expr_1 (value_range_t *vr,
 		 and all numbers from min to 0 for negative min.  */
 	      cmp = compare_values (vr0.max, zero);
 	      if (cmp == -1)
+		{
+		  /* When vr0.max < 0, vr1.min != 0 and value
+		     ranges for dividend and divisor are available.  */
+		  if (vr1.type == VR_RANGE
+		      && !symbolic_range_p (&vr0)
+		      && !symbolic_range_p (&vr1)
+		      && !compare_values (vr1.min, zero))
+		    max = int_const_binop (code, vr0.max, vr1.min);
+		  else
 		    max = zero;
+		}
 	      else if (cmp == 0 || cmp == 1)
 		max = vr0.max;
 	      else
 		type = VR_VARYING;
 	      cmp = compare_values (vr0.min, zero);
 	      if (cmp == 1)
+		{
+		  /* For unsigned division when value ranges for dividend
+		     and divisor are available.  */
+		  if (vr1.type == VR_RANGE
+		      && !symbolic_range_p (&vr0)
+		      && !symbolic_range_p (&vr1))
+		    min = int_const_binop (code, vr0.min, vr1.max);
+		  else
 		    min = zero;
+		}
 	      else if (cmp == 0 || cmp == -1)
 		min = vr0.min;
 	      else