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Re: Big find_cross_jump performance regression.
- To: matzmich at cs dot tu-berlin dot de (Michael Matz)
- Subject: Re: Big find_cross_jump performance regression.
- From: Brad Lucier <lucier at math dot purdue dot edu>
- Date: Thu, 25 May 2000 20:41:23 -0500 (EST)
- Cc: lucier at math dot purdue dot edu (Brad Lucier), gcc at gcc dot gnu dot org, feeley at iro dot umontreal dot ca
> Meanwhile, because I'm curious, can you change in jump_optimize_1() all
> calls to find_cross_jump() to not use BRANCH_COST in the third argument
> but instead simply have a 2 there (as the whole third argument), as in
> find_cross_jump(foo, bar, 2, &bla, &baz) and measure again? I'm just
> interested if it has any effect, but as I simply can't reproduce...
Bingo. I basically reverted the patch
http://gcc.gnu.org/ml/gcc-cvs/2000-05/msg00414.html
installed by Richard Henderson on May 18 in response to an example of mine of
poor jump code generation on the alpha :-) and the main loop in jump_optimize_1
was executed only 19 times, 17 of which were caused by the same reasons as
before.
The new output of gcov on jump.c when run on this file is at
http://www.math.purdue.edu/~lucier/jump-new.c.gcov.gz
Brad