diff options
| author | Richard Biener <rguenther@suse.de> | 2019-11-11 16:07:54 +0000 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2019-11-11 16:07:54 +0000 |
| commit | 455ea308e16e9681595b59521b18f466757f54fc (patch) | |
| tree | cb786dce6b9a80998dcc16a9c4561e7d58ba1541 /gcc/tree-ssa-reassoc.c | |
| parent | f417c3356799147b4f4f8439b1da3526d9c880e7 (diff) | |
2019-11-11 Richard Biener <rguenther@suse.de>
Backport from mainline
2019-06-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/90930
* tree-ssa-reassoc.c (reassociate_bb): Only rewrite expression
into parallel form in the last pass instance.
* gcc.dg/tree-ssa/reassoc-24.c: Adjust.
* gcc.dg/tree-ssa/reassoc-25.c: Likewise.
git-svn-id: https://gcc.gnu.org/svn/gcc/branches/gcc-9-branch@278059 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-ssa-reassoc.c')
| -rw-r--r-- | gcc/tree-ssa-reassoc.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c index 7161c4c36c3..6794fbde29e 100644 --- a/gcc/tree-ssa-reassoc.c +++ b/gcc/tree-ssa-reassoc.c @@ -6013,12 +6013,7 @@ reassociate_bb (basic_block bb) { machine_mode mode = TYPE_MODE (TREE_TYPE (lhs)); int ops_num = ops.length (); - int width = get_reassociation_width (ops_num, rhs_code, mode); - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, - "Width = %d was chosen for reassociation\n", width); - + int width; /* For binary bit operations, if there are at least 3 operands and the last last operand in OPS is a constant, @@ -6032,10 +6027,21 @@ reassociate_bb (basic_block bb) && TREE_CODE (ops.last ()->op) == INTEGER_CST) std::swap (*ops[0], *ops[ops_num - 1]); - if (width > 1 - && ops.length () > 3) - rewrite_expr_tree_parallel (as_a <gassign *> (stmt), - width, ops); + /* Only rewrite the expression tree to parallel in the + last reassoc pass to avoid useless work back-and-forth + with initial linearization. */ + if (!reassoc_insert_powi_p + && ops.length () > 3 + && (width = get_reassociation_width (ops_num, rhs_code, + mode)) > 1) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Width = %d was chosen for reassociation\n", + width); + rewrite_expr_tree_parallel (as_a <gassign *> (stmt), + width, ops); + } else { /* When there are three operands left, we want |