https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103948
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rguenth at gcc dot gnu.org --- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> --- I guess that tree-vect-generic.c is not up-to-date with gimple-isel.cc. We should probably somehow factor out relevant pieces. Note vector lowering will see _1 = a_2(D) > b_3(D); _4 = VEC_COND_EXPR <_1, { -1, -1 }, { 0, 0 }>; and clearly a if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code)) that's just type/code based cannot know expanding just a comparison will work fine. It does look like expand_vector_condition from vector lowering needs some work. Maybe the following works though: diff --git a/gcc/tree-vect-generic.c b/gcc/tree-vect-generic.c index 6afb6999cd7..5814a71a5bb 100644 --- a/gcc/tree-vect-generic.c +++ b/gcc/tree-vect-generic.c @@ -1052,7 +1052,9 @@ expand_vector_condition (gimple_stmt_iterator *gsi, bitmap dce_ssa_names) } } - if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code)) + if (expand_vec_cond_expr_p (type, TREE_TYPE (a1), code) + || (integer_all_onesp (b) && integer_zerop (c) + && expand_vec_cmp_expr_p (type, TREE_TYPE (a1), code))) { gcc_assert (TREE_CODE (a) == SSA_NAME || TREE_CODE (a) == VECTOR_CST); return true; obviously missing would be the case cmp ? { 0, 0 } : { -1, -1 } via code inversion, not sure if we canonicalize that way already and not sure if expansion later will pick that up correctly. A vector mode with just vec_cmp and not vcond will be good to have to cover all this with testcases ... ;) If the above works it's pre-approved.