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| author | Richard Biener <rguenther@suse.de> | 2021-11-03 13:26:48 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2021-11-03 15:00:10 +0100 |
| commit | 1967fd8f2197f2b0334ab0fbc26abc3d9efe56c9 (patch) | |
| tree | 13ffd45ae9f6e550e02db50366844ebe6e7da8d7 /gcc/tree-ssa-pre.c | |
| parent | 67b0d47e20e655c0dd53a76ea88aab60fafb2059 (diff) | |
| download | gcc-1967fd8f2197f2b0334ab0fbc26abc3d9efe56c9.zip gcc-1967fd8f2197f2b0334ab0fbc26abc3d9efe56c9.tar.gz gcc-1967fd8f2197f2b0334ab0fbc26abc3d9efe56c9.tar.bz2 | |
tree-optimization/102970 - remap cliques when translating over backedges
The following makes sure to remap (or rather drop for simplicity)
dependence info encoded in MR_DEPENDENCE_CLIQUE when PRE PHI translation
translates a reference over a backedge since that ends up interleaving
two different loop iterations which boils down to two different
inline copies.
2021-11-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/102970
* tree-ssa-pre.c (phi_translate_1): Drop clique and base
when translating a MEM_REF over a backedge.
* g++.dg/opt/pr102970.C: New testcase.
Diffstat (limited to 'gcc/tree-ssa-pre.c')
| -rw-r--r-- | gcc/tree-ssa-pre.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index 1cc1aae..dc55d86 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -1588,6 +1588,21 @@ phi_translate_1 (bitmap_set_t dest, newoperands.release (); return NULL; } + /* When we translate a MEM_REF across a backedge and we have + restrict info that's not from our functions parameters + we have to remap it since we now may deal with a different + instance where the dependence info is no longer valid. + See PR102970. Note instead of keeping a remapping table + per backedge we simply throw away restrict info. */ + if ((newop.opcode == MEM_REF + || newop.opcode == TARGET_MEM_REF) + && newop.clique > 1 + && (e->flags & EDGE_DFS_BACK)) + { + newop.clique = 0; + newop.base = 0; + changed = true; + } if (!changed) continue; if (!newoperands.exists ()) |