https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107647
--- Comment #15 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
I'm confused about the first hunk in the attached patch:
--- a/gcc/tree-vect-slp-patterns.cc
+++ b/gcc/tree-vect-slp-patterns.cc
@@ -1035,8 +1035,10 @@ complex_mul_pattern::matches (complex_operation_t op,
auto_vec<slp_tree> left_op, right_op;
slp_tree add0 = NULL;
- /* Check if we may be a multiply add. */
+ /* Check if we may be a multiply add. It's only valid to form FMAs
+ with -ffp-contract=fast. */
if (!mul0
+ && flag_fp_contract_mode != FP_CONTRACT_FAST
&& vect_match_expression_p (l0node[0], PLUS_EXPR))
{
auto vals = SLP_TREE_CHILDREN (l0node[0]);
Shouldn't it be ' == FP_CONTRACT_FAST' rather than '!='? It seems we are
checking that a match is found and contracting across statement boundaries is
allowed.
