MATCH: Make zero_one_valued_p non-recursive fully

So it turns out VN can't handle any kind of recursion for match. In this
case we have `b = a & -1` and we try to match a as being zero_one_valued_p
and VN returns b as being the value and we just go into an infinite loop at
this point.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Note genmatch should warn (or error out) if this gets detected so I filed PR 111446
which I will be looking into next week or the week after so we don't run into
this issue again.

	PR tree-optimization/111442

gcc/ChangeLog:

	* match.pd (zero_one_valued_p): Have the bit_and match not be
	recursive.

gcc/testsuite/ChangeLog:

	* gcc.c-torture/compile/pr111442-1.c: New test.

diff --git a/gcc/match.pd b/gcc/match.pd
index a405c9ff6f82fa2c440f3ee61fab8bab90179468..bef513aaa3f0acbe55565e5efc232a042b456d26 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2183,8 +2183,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* (a&1) is always [0,1] too. This is useful again when
    the range is not known. */
+/* Note this can't be recursive due to VN handling of equivalents,
+   VN and would cause an infinite recursion. */
 (match zero_one_valued_p
- (bit_and:c@0 @1 zero_one_valued_p))
+ (bit_and:c@0 @1 integer_onep)
+ (if (INTEGRAL_TYPE_P (type))))
 
 /* A conversion from an zero_one_valued_p is still a [0,1].
    This is useful when the range of a variable is not known */

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr111442-1.c b/gcc/testsuite/gcc.c-torture/compile/pr111442-1.c
new file mode 100644 (file)
index 0000000..5814ee9
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr111442-1.c
@@ -0,0 +1,13 @@
+
+int *a, b;
+int main() {
+  int d = 1, e;
+  if (d)
+    e = a ? 0 % 0 : 0;
+  if (d)
+    a = &d;
+  d = -1;
+  b = d & e;
+  b = 2 * e ^ 1;
+  return 0;
+}