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| author | Richard Biener <rguenther@suse.de> | 2014-06-26 11:29:34 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2014-06-26 11:29:34 +0000 |
| commit | 73c7d6bc25d9bb86bdb81283d237a5b94607ac8c (patch) | |
| tree | 1c939200ec3ae5f46afa0de763e00de9f4d4e65b /gcc/tree-ssa-copy.c | |
| parent | 1d805a56b6a5c2252baccd257e00a719a22ad143 (diff) | |
| download | gcc-73c7d6bc25d9bb86bdb81283d237a5b94607ac8c.zip gcc-73c7d6bc25d9bb86bdb81283d237a5b94607ac8c.tar.gz gcc-73c7d6bc25d9bb86bdb81283d237a5b94607ac8c.tar.bz2 | |
re PR tree-optimization/61607 (DOM missed jump threading and destroyed loops)
2014-06-26 Richard Biener <rguenther@suse.de>
PR tree-optimization/61607
* tree-ssa-copy.c (copy_prop_visit_phi_node): Adjust comment
explaining why we restrict copies on loop depth.
* tree-ssa-dom.c (cprop_operand): Remove restriction on
on loop depth.
(record_equivalences_from_phis): Instead add it here.
* gcc.dg/tree-ssa/ssa-dom-thread-5.c: New testcase.
From-SVN: r212026
Diffstat (limited to 'gcc/tree-ssa-copy.c')
| -rw-r--r-- | gcc/tree-ssa-copy.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c index 1d404d2..0ba665b 100644 --- a/gcc/tree-ssa-copy.c +++ b/gcc/tree-ssa-copy.c @@ -401,11 +401,8 @@ copy_prop_visit_phi_node (gimple phi) arg_value = valueize_val (arg); /* Avoid copy propagation from an inner into an outer loop. - Otherwise, this may move loop variant variables outside of - their loops and prevent coalescing opportunities. If the - value was loop invariant, it will be hoisted by LICM and - exposed for copy propagation. - ??? The value will be always loop invariant. + Otherwise, this may introduce uses of loop variant variables + outside of their loops and prevent coalescing opportunities. In loop-closed SSA form do not copy-propagate through PHI nodes in blocks with a loop exit edge predecessor. */ if (TREE_CODE (arg_value) == SSA_NAME |