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| author | aldyh <aldyh@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-03-09 20:05:08 +0000 |
|---|---|---|
| committer | aldyh <aldyh@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-03-09 20:05:08 +0000 |
| commit | 161fe168cd083534da50aa1d414d24794a5d8164 (patch) | |
| tree | c9430a0a92da8d81b5ec3f994b8012825972f9ba /gcc/tree-ssa-dse.c | |
| parent | ef005ed0ac0f0d8429d6aaa8768bf726369be3ab (diff) | |
| download | gcc-161fe168cd083534da50aa1d414d24794a5d8164.tar.gz | |
PR tree-optimization/30375
* tree-ssa-dse.c (dse_possible_dead_store_p): Do not eliminate if
LHS of statements is not the same.
* testsuite/gcc.dg/tree-ssa/ssa-dse-10.c: New.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@122758 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-ssa-dse.c')
| -rw-r--r-- | gcc/tree-ssa-dse.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c index ed1a5b2a381..bb5d14d78f9 100644 --- a/gcc/tree-ssa-dse.c +++ b/gcc/tree-ssa-dse.c @@ -283,6 +283,32 @@ dse_possible_dead_store_p (tree stmt, gcc_assert (*use_p != NULL_USE_OPERAND_P); *first_use_p = *use_p; + /* In the case of memory partitions, we may get: + + # MPT.764_162 = VDEF <MPT.764_161(D)> + x = {}; + # MPT.764_167 = VDEF <MPT.764_162> + y = {}; + + So we must make sure we're talking about the same LHS. + */ + if (TREE_CODE (temp) == GIMPLE_MODIFY_STMT) + { + tree base1 = get_base_address (GIMPLE_STMT_OPERAND (stmt, 0)); + tree base2 = get_base_address (GIMPLE_STMT_OPERAND (temp, 0)); + + while (base1 && INDIRECT_REF_P (base1)) + base1 = TREE_OPERAND (base1, 0); + while (base2 && INDIRECT_REF_P (base2)) + base2 = TREE_OPERAND (base2, 0); + + if (base1 != base2) + { + fail = true; + break; + } + } + /* If the immediate use of DEF_VAR is not the same as the previously find immediate uses, then we will not be able to eliminate STMT. */ |