diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/tree-ssa-dce.c | 16 |
2 files changed, 18 insertions, 4 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2666821..b6eb7c5 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2009-11-26 Richard Guenther <rguenther@suse.de> + + * tree-ssa-dce.c (nr_walks): New variable. + (mark_aliased_reaching_defs_necessary): Adjust oracle cut-off. + (perform_tree_ssa_dce): Init nr_walks. + 2009-11-26 Michael Matz <matz@suse.de> PR tree-optimization/41905 diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c index 0ddda76..cdb6432 100644 --- a/gcc/tree-ssa-dce.c +++ b/gcc/tree-ssa-dce.c @@ -489,6 +489,7 @@ ref_may_be_aliased (tree ref) static bitmap visited = NULL; static unsigned int longest_chain = 0; static unsigned int total_chain = 0; +static unsigned int nr_walks = 0; static bool chain_ovfl = false; /* Worker for the walker that marks reaching definitions of REF, @@ -557,6 +558,7 @@ mark_aliased_reaching_defs_necessary (gimple stmt, tree ref) if (chain > longest_chain) longest_chain = chain; total_chain += chain; + nr_walks++; } /* Worker for the walker that marks reaching definitions of REF, which @@ -803,11 +805,16 @@ propagate_necessity (struct edge_list *el) gcc_unreachable (); /* If we over-used our alias oracle budget drop to simple - mode. The cost metric allows quadratic behavior up to - a constant maximal chain and after that falls back to + mode. The cost metric allows quadratic behavior + (number of uses times number of may-defs queries) up to + a constant maximal number of queries and after that falls back to super-linear complexity. */ - if (longest_chain > 256 - && total_chain > 256 * longest_chain) + if (/* Constant but quadratic for small functions. */ + total_chain > 128 * 128 + /* Linear in the number of may-defs. */ + && total_chain > 32 * longest_chain + /* Linear in the number of uses. */ + && total_chain > nr_walks * 32) { chain_ovfl = true; if (visited) @@ -1376,6 +1383,7 @@ perform_tree_ssa_dce (bool aggressive) longest_chain = 0; total_chain = 0; + nr_walks = 0; chain_ovfl = false; visited = BITMAP_ALLOC (NULL); propagate_necessity (el); |