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| author | Jeff Law <law@redhat.com> | 2005-11-04 13:09:25 -0700 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2005-11-04 13:09:25 -0700 |
| commit | 43f31be5b702402e76289ae304045d8a91bc7437 (patch) | |
| tree | ad9cd6b26ccb8f5631c14579e9c4b7fc9941c67e /gcc/tree-ssa-dom.c | |
| parent | 8b1062b24b37fcda9a94ad655e73e9352abcd3a0 (diff) | |
| download | gcc-43f31be5b702402e76289ae304045d8a91bc7437.zip gcc-43f31be5b702402e76289ae304045d8a91bc7437.tar.gz gcc-43f31be5b702402e76289ae304045d8a91bc7437.tar.bz2 | |
invoke.texi: Document max-jump-thread-duplication-stmts PARAM.
* doc/invoke.texi: Document max-jump-thread-duplication-stmts PARAM.
* tree-ssa-dom.c: Include params.h.
(thread_across_edge): If there are too many statements in the
target block, then do not thread through it.
* Makefile.in (tree-ssa-dom.o): Depend on $(PARAMS_H).
* params.def (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS): New PARAM.
From-SVN: r106503
Diffstat (limited to 'gcc/tree-ssa-dom.c')
| -rw-r--r-- | gcc/tree-ssa-dom.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index b37df77..cb5eeb0 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -42,6 +42,7 @@ Boston, MA 02110-1301, USA. */ #include "tree-pass.h" #include "tree-ssa-propagate.h" #include "langhooks.h" +#include "params.h" /* This file implements optimizations on the dominator tree. */ @@ -608,6 +609,9 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e) block_stmt_iterator bsi; tree stmt = NULL; tree phi; + int stmt_count = 0; + int max_stmt_count; + /* If E->dest does not end with a conditional, then there is nothing to do. */ @@ -637,6 +641,11 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e) tree src = PHI_ARG_DEF_FROM_EDGE (phi, e); tree dst = PHI_RESULT (phi); + /* Do not include virtual PHIs in our statement count as + they never generate code. */ + if (is_gimple_reg (dst)) + stmt_count++; + /* If the desired argument is not the same as this PHI's result and it is set by a PHI in E->dest, then we can not thread through E->dest. */ @@ -664,6 +673,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e) Failure to simplify into the form above merely means that the statement provides no equivalences to help simplify later statements. This does not prevent threading through E->dest. */ + max_stmt_count = PARAM_VALUE (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS); for (bsi = bsi_start (e->dest); ! bsi_end_p (bsi); bsi_next (&bsi)) { tree cached_lhs = NULL; @@ -674,6 +684,12 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e) if (IS_EMPTY_STMT (stmt) || TREE_CODE (stmt) == LABEL_EXPR) continue; + /* If duplicating this block is going to cause too much code + expansion, then do not thread through this block. */ + stmt_count++; + if (stmt_count > max_stmt_count) + return; + /* Safely handle threading across loop backedges. This is over conservative, but still allows us to capture the majority of the cases where we can thread across a loop |