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[Bug target/36713] [4.4 regression] r137252 breaks -O2 optimization on x86_64-unknown-linux-gnu
- From: "dfranke at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Jul 2008 11:42:13 -0000
- Subject: [Bug target/36713] [4.4 regression] r137252 breaks -O2 optimization on x86_64-unknown-linux-gnu
- References: <bug-36713-13648@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from dfranke at gcc dot gnu dot org 2008-07-03 11:42 -------
Differences in *.optimized dumps seem to be variable renaming only, e.g.
- temp.1140 = tdata->p;
+ temp.1137 = tdata->p;
Differences in *.alias seems to be mostly of the kind:
-PARM_NOALIAS.895 = &ANYTHING
+PARM_NOALIAS.895 = &ESCAPED
However, I also found:
-PARM_NOALIAS.895 = { ANYTHING ESCAPED NONLOCAL }
-D.3410_6 = same as thread_data
-thread_data = { ANYTHING }
-D.3411_7 = same as thread_data
+PARM_NOALIAS.895 = { ESCAPED NONLOCAL }
+D.3410_6 = same as derefaddrtmp.893
+thread_data = same as derefaddrtmp.893 <---- ?!?
+D.3411_7 = same as derefaddrtmp.893
which might hint at the problem: the variable thread_data is an allocated
POINTER to a vector of structures (which hold more pointers), public within a
module. USE-ing it, makes it (sort of) local to the function. Most (>80% of
all) changes in *.optimized where in the one source file that uses this module
...
Richard, would this fit the bill?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36713