From 25127123100f04c2d5d70c6933a5f5aedcd69c40 Mon Sep 17 00:00:00 2001 From: Tamar Christina Date: Wed, 3 Jul 2024 09:30:28 +0100 Subject: [PATCH] ivopts: fix wide_int_constant_multiple_p when VAL and DIV are 0. [PR114932] wide_int_constant_multiple_p tries to check if for two tree expressions a and b that there is a multiplier which makes a == b * c. This code however seems to think that there's no c where a=0 and b=0 are equal which is of course wrong. This fixes it and also fixes the comment. gcc/ChangeLog: PR tree-optimization/114932 * tree-affine.cc (wide_int_constant_multiple_p): Support 0 and 0 being multiples. --- gcc/tree-affine.cc | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/gcc/tree-affine.cc b/gcc/tree-affine.cc index d6309c439036..76117aa4fd6d 100644 --- a/gcc/tree-affine.cc +++ b/gcc/tree-affine.cc @@ -880,11 +880,11 @@ free_affine_expand_cache (hash_map **cache) *cache = NULL; } -/* If VAL != CST * DIV for any constant CST, returns false. - Otherwise, if *MULT_SET is true, additionally compares CST and MULT, - and if they are different, returns false. Finally, if neither of these - two cases occur, true is returned, and CST is stored to MULT and MULT_SET - is set to true. */ +/* If VAL == CST * DIV for any constant CST, returns true. + and if *MULT_SET is true, additionally compares CST and MULT + and if they are different, returns false. If true is returned, CST is + stored to MULT and MULT_SET is set to true unless VAL and DIV are both zero + in which case neither MULT nor MULT_SET are updated. */ static bool wide_int_constant_multiple_p (const poly_widest_int &val, @@ -895,6 +895,9 @@ wide_int_constant_multiple_p (const poly_widest_int &val, if (known_eq (val, 0)) { + if (known_eq (div, 0)) + return true; + if (*mult_set && maybe_ne (*mult, 0)) return false; *mult_set = true; -- 2.43.5