[Bug tree-optimization/33928] [4.3/4.4 Regression] 22% performance slowdown from 4.2.2 to 4.3/4.4.0 in floating-point code

[bonzini at gnu dot org]

------- Comment #40 from bonzini at gnu dot org  2008-12-07 02:55 -------
IIUC this is a typical case in which CSE was fixing something that earlier
passes messed up.  Unfortunately fwprop does (better) what CSE was meant to do,
but does not do what I assumed was already done before CSE.

If the problem is aliasing/FRE, then I think Richi is the one who could fix it
for good in the tree passes.  If there is more to it, however, I can take a
look at why fwprop is generating the ugly code.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33928