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| author | Andrew Pinski <quic_apinski@quicinc.com> | 2024-04-28 20:21:02 -0700 |
|---|---|---|
| committer | Andrew Pinski <quic_apinski@quicinc.com> | 2024-04-30 09:11:55 -0700 |
| commit | a30d2e6bd0b965e7687f58530a767a3c3b079158 (patch) | |
| tree | 526b9e2f4da08b9b37631449c7fdc46673e5a7fb | |
| parent | 611815e0233302e1fcccca113e6f865fa450b7ae (diff) | |
PHIOPT: Value-replacement check undef
While moving value replacement part of PHIOPT over
to use match-and-simplify, I ran into the case where
we would have an undef use that was conditional become
unconditional. This prevents that. I can't remember at this
point what the testcase was though.
Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
* tree-ssa-phiopt.cc (value_replacement): Reject undef variables
so they don't become unconditional used.
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
| -rw-r--r-- | gcc/tree-ssa-phiopt.cc | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc index a2bdcb5eae8..f166c3132cb 100644 --- a/gcc/tree-ssa-phiopt.cc +++ b/gcc/tree-ssa-phiopt.cc @@ -1146,6 +1146,13 @@ value_replacement (basic_block cond_bb, basic_block middle_bb, if (code != NE_EXPR && code != EQ_EXPR) return 0; + /* Do not make conditional undefs unconditional. */ + if ((TREE_CODE (arg0) == SSA_NAME + && ssa_name_maybe_undef_p (arg0)) + || (TREE_CODE (arg1) == SSA_NAME + && ssa_name_maybe_undef_p (arg1))) + return false; + /* If the type says honor signed zeros we cannot do this optimization. */ if (HONOR_SIGNED_ZEROS (arg1)) |