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[Bug rtl-optimization/59535] [4.9 regression] -Os code size regressions for Thumb1/Thumb2 with LRA
- From: "vmakarov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 18 Dec 2013 16:06:26 +0000
- Subject: [Bug rtl-optimization/59535] [4.9 regression] -Os code size regressions for Thumb1/Thumb2 with LRA
- Auto-submitted: auto-generated
- References: <bug-59535-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59535
Vladimir Makarov <vmakarov at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |vmakarov at gcc dot gnu.org
--- Comment #9 from Vladimir Makarov <vmakarov at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #5)
> Number of register-register move operations in the testcase
> lra: 208
> no-lra: 105
That is huge degradation. And I guess it is not only because of 2-ops insns.
It works adequate on x86/x86-64. Although I know some issues with 2-ops
commutative insns (I am trying to fix it too).
I think major problem is in wrong alternative choices as thumb lo/hi reg usage
is complicated.
I take this bug very seriously. If I cannot fix it till end of Jan (sorry, it
is a vacation time), probably we should switch to reload pass for thumb.