------- Comment #45 from lucier at math dot purdue dot edu 2009-02-13 16:09 ------- Subject: Re: [4.3/4.4 Regression] 30% performance slowdown in floating-point code caused by r118475
On Fri, 2009-02-13 at 16:05 +0000, bonzini at gnu dot org wrote: > ------- Comment #44 from bonzini at gnu dot org 2009-02-13 16:05 ------- > A simplified (local, noncascading) fwprop not using UD chains would not be > hard > to do... Basically, at -O1 use FOR_EACH_BB/FOR_EACH_BB_INSN instead of > walking > the uses, keep a (regno, insn) map of pseudos (cleared at the beginning of > every basic block), and use that info instead of UD chains in > use_killed_between... As noted in comment 42, enabling FWPROP on this test case does not fix the performance problem. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33928
