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[Bug middle-end/32624] [4.3 Regression] r126198 causes tramp3d slowdown w/o leafify
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 22 Nov 2007 13:28:25 -0000
- Subject: [Bug middle-end/32624] [4.3 Regression] r126198 causes tramp3d slowdown w/o leafify
- References: <bug-32624-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from rguenth at gcc dot gnu dot org 2007-11-22 13:28 -------
Created an attachment (id=14606)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14606&action=view)
patch doing TBAA pruning on the access site
But this patch makes the regression in the particular function go away. In
other functions the alias information would allow hoisting invariant loads
after
this patch but neither PRE nor LIM do it there, possibly because they do not
try to prove that
# VUSE <SMT.20637_172(D)>
D.627356_122 = p_121->engine_m.data_m;
cannot trap (I'm not 100% sure that can be proven). The patch doesn't cause
any notable performance improvement though (probably because of the above
reason). Also the missing V_MUST_DEFs cause missing propagation/dce of
trivial copies in arrays.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32624