This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug middle-end/32964] [4.3 Regression] union cause inefficient code inside loops
- 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: 4 Jan 2008 16:59:26 -0000
- Subject: [Bug middle-end/32964] [4.3 Regression] union cause inefficient code inside loops
- References: <bug-32964-6528@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from rguenth at gcc dot gnu dot org 2008-01-04 16:59 -------
The plain DECL does not work because
1) we don't do the storetmp
2) can_PRE_operation and can_value_number_operation return false (so we
do not enter a into EXP_GEN
3) create_value_expr_from cannot handle it
most of the rest of PRE looks like it may handle DECLs, but if you fix the
above, vn_lookup_with_vuses still not finds VH.10, because it is not ANTIC_IN.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32964