[Bug rtl-optimization/37534] [4.4 Regression] IRA causes 17% degradation in 187.facerec benchmark

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2008-09-16 01:04 -------
The first thing I noticed (this for both with/without IRA), is that we are
moving from cr and then comparing right away:
+       mfcr %r0,1
+       rlwinm %r0,%r0,30,1
...
+       cmpdi %cr7,%r0,0

Why is that?

The other thing I noticed for the tree level (still without/with IRA), is that
FRAME.98 is not SRA'ed because we take the address of one of the elements even
though we know that cannot be done on the normal pointer tricks on it (see PR
17217 which I had forgot to reopen when the code was disabled).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37534