diff options
| author | dberlin <dberlin@138bc75d-0d04-0410-961f-82ee72b054a4> | 2004-06-14 01:27:57 +0000 |
|---|---|---|
| committer | dberlin <dberlin@138bc75d-0d04-0410-961f-82ee72b054a4> | 2004-06-14 01:27:57 +0000 |
| commit | b876c4f049a16e9f44a52b9aed20c20562767b0a (patch) | |
| tree | 14c168f85c8b4c078f80f0133136eaac2cd75da9 /gcc/tree-ssa-pre.c | |
| parent | 2feb741e9cce4ede6a63d29ceee25900d104489a (diff) | |
| download | gcc-b876c4f049a16e9f44a52b9aed20c20562767b0a.tar.gz | |
2004-06-13 Daniel Berlin <dberlin@dberlin.org>
Fix PR tree-optimization/15979
Fix PR tree-optimization/15981
* tree-ssa-pre.c (insert_aux): Fix faulty logic so that we don't
try to insert values undefined along some path.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@83076 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-ssa-pre.c')
| -rw-r--r-- | gcc/tree-ssa-pre.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index b0d42ff05f3..c2853296cf5 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -1279,6 +1279,8 @@ insert_aux (basic_block block) edge pred; basic_block bprime; tree eprime; + bool cant_insert = false; + val = get_value_handle (node->expr); if (set_contains_value (PHI_GEN (block), val)) continue; @@ -1288,9 +1290,8 @@ insert_aux (basic_block block) fprintf (dump_file, "Found fully redundant value\n"); continue; } - - - avail = xcalloc (last_basic_block, sizeof (tree)); + + avail = xcalloc (last_basic_block, sizeof (tree)); for (pred = block->pred; pred; pred = pred->pred_next) @@ -1301,8 +1302,21 @@ insert_aux (basic_block block) eprime = phi_translate (node->expr, ANTIC_IN (block), bprime, block); + + /* eprime will generally only be NULL if the + value of the expression, translated + through the PHI for this predecessor, is + undefined. If that is the case, we can't + make the expression fully redundant, + because its value is undefined along a + predecessor path. We can thus break out + early because it doesn't matter what the + rest of the results are. */ if (eprime == NULL) - continue; + { + cant_insert = true; + break; + } vprime = get_value_handle (eprime); if (!vprime) @@ -1328,7 +1342,7 @@ insert_aux (basic_block block) } } - if (!all_same && by_some) + if (!cant_insert && !all_same && by_some) { tree temp; tree type = TREE_TYPE (avail[block->pred->src->index]); |