If the LHS does not contain zero, neither do multiply operands.

Given ~[0,0] = op1 * op2, range-ops should determine that neither op1 nor
op2 is zero.  Add this to the operator_mult for op1_range.  op2_range
simply invokes op1_range, so both will be covered.

	PR tree-optimzation/110992.c
	PR tree-optimzation/119471.c
	gcc/
	* range-op.cc (operator_mult::op1_range): If the LHS does not
	contain zero, return non-zero.

	gcc/testsuite/
	* gcc.dg/pr110992.c: New.
	* gcc.dg/pr119471.c: New.

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 6310ce27f03c449bcfc29b4b27358c67fe27cca4..f72b4ae92cfd88ef46a4b0d98a71f0108f965aa5 100644 (file)
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -2220,6 +2220,13 @@ operator_mult::op1_range (irange &r, tree type,
   wide_int offset;
   if (op2.singleton_p (offset) && offset != 0)
     return range_op_handler (TRUNC_DIV_EXPR).fold_range (r, type, lhs, op2);
+
+  //  ~[0, 0] = op1 * op2  defines op1 and op2 as non-zero.
+  if (!lhs.contains_p (wi::zero (TYPE_PRECISION (lhs.type ()))))
+    {
+      r.set_nonzero (type);
+      return true;
+    }
   return false;
 }
 

diff --git a/gcc/testsuite/gcc.dg/pr110992.c b/gcc/testsuite/gcc.dg/pr110992.c
new file mode 100644 (file)
index 0000000..05e9b92
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110992.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+void foo (int);
+
+int f(unsigned b, short c)
+{
+  int bt = b;
+  int bt1 = bt;
+  int t = bt1 & -(c!=0);
+ // int t = bt1 * (c!=0);
+
+  if (!t) return 0;
+  foo(bt == 0);
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "foo \\(0\\)" 1 "evrp" } } */

diff --git a/gcc/testsuite/gcc.dg/pr119471.c b/gcc/testsuite/gcc.dg/pr119471.c
new file mode 100644 (file)
index 0000000..4c55d85
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr119471.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+int fa(int a, int b)
+{
+  int c = a * b;
+  if (c != 0)
+    return (a != 0);
+  return 0;
+}
+int fb(int a, int b)
+{
+  int c = a * b;
+  if (c != 0)
+    return (b != 0);
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "PHI <1" 2 "evrp" } } */