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| author | Steven Bosscher <stevenb@suse.de> | 2005-02-01 10:03:15 +0000 |
|---|---|---|
| committer | Steven Bosscher <steven@gcc.gnu.org> | 2005-02-01 10:03:15 +0000 |
| commit | bbcb0c056be0883aa970eb5552bb713d516d9c1e (patch) | |
| tree | 87553ed6cbe3253976ee763b34f7a58ef2a27ed1 /gcc/doc/invoke.texi | |
| parent | e88334a68f98bc5ca30180787f9c67512b568ab7 (diff) | |
| download | gcc-bbcb0c056be0883aa970eb5552bb713d516d9c1e.zip gcc-bbcb0c056be0883aa970eb5552bb713d516d9c1e.tar.gz gcc-bbcb0c056be0883aa970eb5552bb713d516d9c1e.tar.bz2 | |
re PR rtl-optimization/15242 (pessimization of "goto *")
PR optimization/15242
* params.def (PARAM_MAX_GOTO_DUPLICATION_INSNS): New param.
* basic-block.h (duplicate_computed_gotos): Add prototype.
* bb-reorder.c (duplicate_computed_gotos): New function to
duplicate sufficiently small blocks ending in a computed jump.
* passes.c (rest_of_compilation): Call duplicate_computed_gotos
if not optimizing for size.
* cfgcleanup.c (try_crossjump_bb): If not optimizing for size,
never do tail merging for blocks ending in a computed jump.
* doc/invoke.texi: Document the max-goto-duplication-insns param.
From-SVN: r94531
Diffstat (limited to 'gcc/doc/invoke.texi')
| -rw-r--r-- | gcc/doc/invoke.texi | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index b58cd41..1247f64 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -5344,6 +5344,14 @@ of two blocks before crossjumping will be performed on them. This value is ignored in the case where all instructions in the block being crossjumped from are matched. The default value is 5. +@item max-goto-duplication-insns +The maximum number of instructions to duplicate to a block that jumps +to a computed goto. To avoid @math{O(N^2)} behavior in a number of +passes, GCC factors computed gotos early in the compilation process, +and unfactors them as late as possible. Only computed jumps at the +end of a basic blocks with no more than max-goto-duplication-insns are +unfactored. The default value is 8. + @item max-delay-slot-insn-search The maximum number of instructions to consider when looking for an instruction to fill a delay slot. If more than this arbitrary number of |