diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/tree-ssa-forwprop.c | 22 |
2 files changed, 23 insertions, 6 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 8507c2e..8f5ec70 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,12 @@ 2020-01-28 Richard Sandiford <richard.sandiford@arm.com> + PR tree-optimization/92822 + * tree-ssa-forwprop.c (simplify_vector_constructor): When filling + out the don't-care elements of a vector whose significant elements + are duplicates, make the don't-care elements duplicates too. + +2020-01-28 Richard Sandiford <richard.sandiford@arm.com> + PR tree-optimization/93434 * tree-predcom.c (split_data_refs_to_components): Record which components have had aliasing loads removed. Prevent store-store diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c index d63e87c..5203891 100644 --- a/gcc/tree-ssa-forwprop.c +++ b/gcc/tree-ssa-forwprop.c @@ -2455,16 +2455,26 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi) it and its source indexes to make the permutation supported. For now it mimics a blend. */ vec_perm_builder sel (refnelts, refnelts, 1); + bool all_same_p = true; for (i = 0; i < elts.length (); ++i) - sel.quick_push (elts[i].second + elts[i].first * refnelts); + { + sel.quick_push (elts[i].second + elts[i].first * refnelts); + all_same_p &= known_eq (sel[i], sel[0]); + } /* And fill the tail with "something". It's really don't care, and ideally we'd allow VEC_PERM to have a smaller destination - vector. As heuristic try to preserve a uniform orig[0] which - facilitates later pattern-matching VEC_PERM_EXPR to a - BIT_INSERT_EXPR. */ + vector. As a heuristic: + + (a) if what we have so far duplicates a single element, make the + tail do the same + + (b) otherwise preserve a uniform orig[0]. This facilitates + later pattern-matching of VEC_PERM_EXPR to a BIT_INSERT_EXPR. */ for (; i < refnelts; ++i) - sel.quick_push ((elts[0].second == 0 && elts[0].first == 0 - ? 0 : refnelts) + i); + sel.quick_push (all_same_p + ? sel[0] + : (elts[0].second == 0 && elts[0].first == 0 + ? 0 : refnelts) + i); vec_perm_indices indices (sel, orig[1] ? 2 : 1, refnelts); if (!can_vec_perm_const_p (TYPE_MODE (perm_type), indices)) return false; |