So it turns out VN can't handle any kind of recusion 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 recusive. gcc/testsuite/ChangeLog: * gcc.c-torture/compile/pr111442-1.c: New test. --- gcc/match.pd | 5 ++++- gcc/testsuite/gcc.c-torture/compile/pr111442-1.c | 13 +++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr111442-1.c diff --git a/gcc/match.pd b/gcc/match.pd index 887665633d4..773c3810f51 100644 --- 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 recusive due to VN handling of equivalents, + VN and would cause an infinite recusion. */ (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 index 00000000000..5814ee938de --- /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; +} -- 2.31.1