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[Bug tree-optimization/35164] [4.3 regression] Unable to coalesce ab SSA_NAMEs
- From: "jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Feb 2008 12:00:16 -0000
- Subject: [Bug tree-optimization/35164] [4.3 regression] Unable to coalesce ab SSA_NAMEs
- References: <bug-35164-87@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #1 from jakub at gcc dot gnu dot org 2008-02-12 12:00 -------
But this one doesn't seem to be inlining related. Until vrp1 pass the var in
question (D.20903) has just one SSA_NAME (D.20903_14) in the whole function,
non-ab, initialized at the beginning of the loop and nothing before the loop or
in loop header can throw. vrp introduces a lot of new SSA_NAMEs for this
variable, now (ab) marked in the dump, but except one are of the form:
# D.20903_627(ab) = PHI <D.20903_14(ab)(5)>
# D.20903_628(ab) = PHI <D.20903_14(ab)(18)>
# D.20903_629(ab) = PHI <D.20903_14(ab)(36)>
and then one:
# D.20903_630(ab) = PHI <D.20903_14(ab)(27), D.20903_628(ab)(25),
D.20903_629(ab)(39), D.20903_14(ab)(42), D.20903_14(ab)(4), D
.20903_627(ab)(8), D.20903_14(ab)(11)>
the 3 are only used in this last PHI, so I wonder what was the point creating
them.
D.20903_630 is then used couple of times and so is the original D.20903_14.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35164