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| author | Jeff Law <law@redhat.com> | 2017-02-21 10:58:00 -0700 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2017-02-21 10:58:00 -0700 |
| commit | 1486c2a780bee75dc5afecdc8b03f28906b2ef04 (patch) | |
| tree | e20843060c099ad84815b9aebcf3148a87cd4912 /gcc/gimple-ssa-isolate-paths.c | |
| parent | 3bb4311904171b4938f6682566a24180f318b196 (diff) | |
| download | gcc-1486c2a780bee75dc5afecdc8b03f28906b2ef04.zip gcc-1486c2a780bee75dc5afecdc8b03f28906b2ef04.tar.gz gcc-1486c2a780bee75dc5afecdc8b03f28906b2ef04.tar.bz2 | |
re PR tree-optimization/79621 (Missed path isolation opportunity)
PR tree-optimization/79621
* gimple-ssa-isolate-paths.c (find_implicit_erroneous_behavior): Ignore
blocks with edges to themselves.
PR tree-optimization/79621
* gcc.c-torture/compile/pr79621.c: New test.
From-SVN: r245637
Diffstat (limited to 'gcc/gimple-ssa-isolate-paths.c')
| -rw-r--r-- | gcc/gimple-ssa-isolate-paths.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/gcc/gimple-ssa-isolate-paths.c b/gcc/gimple-ssa-isolate-paths.c index 25e8c8a..7babe09 100644 --- a/gcc/gimple-ssa-isolate-paths.c +++ b/gcc/gimple-ssa-isolate-paths.c @@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see #include "tree-ssa.h" #include "cfgloop.h" #include "tree-cfg.h" +#include "cfganal.h" #include "intl.h" @@ -352,6 +353,16 @@ find_implicit_erroneous_behavior (void) if (has_abnormal_or_eh_outgoing_edge_p (bb)) continue; + + /* If BB has an edge to itself, then duplication of BB below + could result in reallocation of BB's PHI nodes. If that happens + then the loop below over the PHIs would use the old PHI and + thus invalid information. We don't have a good way to know + if a PHI has been reallocated, so just avoid isolation in + this case. */ + if (find_edge (bb, bb)) + continue; + /* First look for a PHI which sets a pointer to NULL and which is then dereferenced within BB. This is somewhat overly conservative, but probably catches most of the interesting |