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| author | Richard Biener <rguenther@suse.de> | 2020-11-30 13:39:59 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2020-11-30 14:29:57 +0100 |
| commit | ebbe3f29518854c36574adbd4fa82fd56fa64056 (patch) | |
| tree | 94cf39775563bbeaf504bf34ca9b268a08450dd4 /gcc/tree-vect-loop.c | |
| parent | 1e5c644fb62e3e1757cf74fe8a14873d5e8ba53e (diff) | |
| download | gcc-ebbe3f29518854c36574adbd4fa82fd56fa64056.zip gcc-ebbe3f29518854c36574adbd4fa82fd56fa64056.tar.gz gcc-ebbe3f29518854c36574adbd4fa82fd56fa64056.tar.bz2 | |
tree-optimization/98064 - fix BB SLP live lane extract wrt LC SSA
This avoids breaking LC SSA when SLP codegen pulled an out-of-loop
def into a loop when merging with in-loop defs for an external def.
2020-11-30 Richard Biener <rguenther@suse.de>
PR tree-optimization/98064
* tree-vect-loop.c (vectorizable_live_operation): Avoid
breaking LC SSA for BB vectorization.
* g++.dg/vect/pr98064.cc: New testcase.
Diffstat (limited to 'gcc/tree-vect-loop.c')
| -rw-r--r-- | gcc/tree-vect-loop.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 48dfb4d..c8b4dc3 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -8743,6 +8743,24 @@ vectorizable_live_operation (vec_info *vinfo, "def\n"); continue; } + /* ??? It can also happen that we end up pulling a def into + a loop where replacing out-of-loop uses would require + a new LC SSA PHI node. Retain the original scalar in + those cases as well. PR98064. */ + if (TREE_CODE (new_tree) == SSA_NAME + && !SSA_NAME_IS_DEFAULT_DEF (new_tree) + && (gimple_bb (use_stmt)->loop_father + != gimple_bb (vec_stmt)->loop_father) + && !flow_loop_nested_p (gimple_bb (vec_stmt)->loop_father, + gimple_bb (use_stmt)->loop_father)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Using original scalar computation for " + "live lane because there is an out-of-loop " + "definition for it\n"); + continue; + } FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) SET_USE (use_p, new_tree); update_stmt (use_stmt); |