diff options
| author | Patrick Palka <ppalka@gcc.gnu.org> | 2014-11-10 20:43:40 +0000 |
|---|---|---|
| committer | Patrick Palka <ppalka@gcc.gnu.org> | 2014-11-10 20:43:40 +0000 |
| commit | c7488fba456957f70edd5a6bb0464fe336f694c5 (patch) | |
| tree | 5775c1e9ec86f3e40c0415ce897655efa09b8992 /gcc/tree-ssa-propagate.c | |
| parent | 3bbddc8e442eab7b76a5c1a0f63ef5fc647423e0 (diff) | |
re PR tree-optimization/63748 (wrong may be used uninitialized warning (abnormal edges))
2014-11-10 Patrick Palka <ppalka@gcc.gnu.org>
gcc/
PR middle-end/63748
* tree-ssa-propagate.c (may_propagate_copy): Allow propagating
SSA copies whose source and destination names both occur in
abnormal PHIs.
gcc/testsuite/
PR middle-end/63748
* gcc.dg/pr63748.c: New testcase.
From-SVN: r217317
Diffstat (limited to 'gcc/tree-ssa-propagate.c')
| -rw-r--r-- | gcc/tree-ssa-propagate.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/gcc/tree-ssa-propagate.c b/gcc/tree-ssa-propagate.c index 9f4d3811f28..0195afa7f01 100644 --- a/gcc/tree-ssa-propagate.c +++ b/gcc/tree-ssa-propagate.c @@ -1275,21 +1275,24 @@ may_propagate_copy (tree dest, tree orig) tree type_d = TREE_TYPE (dest); tree type_o = TREE_TYPE (orig); - /* If ORIG flows in from an abnormal edge, it cannot be propagated. */ + /* If ORIG is a default definition which flows in from an abnormal edge + then the copy can be propagated. It is important that we do so to avoid + uninitialized copies. */ if (TREE_CODE (orig) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig) - /* If it is the default definition and an automatic variable then - we can though and it is important that we do to avoid - uninitialized regular copies. */ - && !(SSA_NAME_IS_DEFAULT_DEF (orig) - && (SSA_NAME_VAR (orig) == NULL_TREE - || TREE_CODE (SSA_NAME_VAR (orig)) == VAR_DECL))) + && SSA_NAME_IS_DEFAULT_DEF (orig) + && (SSA_NAME_VAR (orig) == NULL_TREE + || TREE_CODE (SSA_NAME_VAR (orig)) == VAR_DECL)) + ; + /* Otherwise if ORIG just flows in from an abnormal edge then the copy cannot + be propagated. */ + else if (TREE_CODE (orig) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)) return false; - - /* If DEST is an SSA_NAME that flows from an abnormal edge, then it - cannot be replaced. */ - if (TREE_CODE (dest) == SSA_NAME - && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest)) + /* Similarly if DEST flows in from an abnormal edge then the copy cannot be + propagated. */ + else if (TREE_CODE (dest) == SSA_NAME + && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest)) return false; /* Do not copy between types for which we *do* need a conversion. */ |