diff options
Diffstat (limited to 'gcc/tree-vect-patterns.c')
| -rw-r--r-- | gcc/tree-vect-patterns.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c index 57c76364b9c..066ec48c056 100644 --- a/gcc/tree-vect-patterns.c +++ b/gcc/tree-vect-patterns.c @@ -3979,6 +3979,20 @@ vect_recog_mask_conversion_pattern (vec<gimple *> *stmts, tree *type_in, } else if (COMPARISON_CLASS_P (rhs1)) { + /* Check whether we're comparing scalar booleans and (if so) + whether a better mask type exists than the mask associated + with boolean-sized elements. This avoids unnecessary packs + and unpacks if the booleans are set from comparisons of + wider types. E.g. in: + + int x1, x2, x3, x4, y1, y1; + ... + bool b1 = (x1 == x2); + bool b2 = (x3 == x4); + ... = b1 == b2 ? y1 : y2; + + it is better for b1 and b2 to use the mask type associated + with int elements rather bool (byte) elements. */ rhs1_type = search_type_for_mask (TREE_OPERAND (rhs1, 0), vinfo); if (!rhs1_type) rhs1_type = TREE_TYPE (TREE_OPERAND (rhs1, 0)); @@ -3992,9 +4006,11 @@ vect_recog_mask_conversion_pattern (vec<gimple *> *stmts, tree *type_in, return NULL; /* Continue if a conversion is needed. Also continue if we have - a comparison whose natural vector type is different from VECTYPE2; - in that case we'll replace the comparison with an SSA name and - behave as though the comparison was an SSA name from the outset. */ + a comparison whose vector type would normally be different from + VECTYPE2 when considered in isolation. In that case we'll + replace the comparison with an SSA name (so that we can record + its vector type) and behave as though the comparison was an SSA + name from the outset. */ if (must_eq (TYPE_VECTOR_SUBPARTS (vectype1), TYPE_VECTOR_SUBPARTS (vectype2)) && (TREE_CODE (rhs1) == SSA_NAME |