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From: "ebotcazou at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/16532] Inefficient jump to epilogue
Date: Wed, 14 Jul 2004 07:43:00 -0000 [thread overview]
Message-ID: <20040714074311.1493.qmail@sourceware.org> (raw)
In-Reply-To: <20040713215437.16532.dann@godzilla.ics.uci.edu>
------- Additional Comments From ebotcazou at gcc dot gnu dot org 2004-07-14 07:43 -------
> It is probably better to just duplicate the epilogue instead of using
> "ba,pt %xcc, .LL1", this is what Forte-7 does (and gcc on x86).
Definitely.
> I don't have mainline gcc built on sparc to see if this is still the case.
We're on the right track on mainline but not yet there. We now can emit the
epilogue anywhere in the function, so mainline compiles the function into:
FirstOne:
save %sp, -112, %sp
sethi %hi(64512), %o5
mov 0, %o4
sllx %i0, 32, %g1
srl %i1, 0, %i1
or %i1, %g1, %g1
srlx %g1, 32, %g1
srlx %g1, 32, %i4
mov %g1, %i5
or %o5, 1023, %o5
and %i4, %o4, %i4
sllx %i0, 32, %g1
srl %i1, 0, %i1
or %i1, %g1, %g1
srlx %g1, 48, %g1
srlx %g1, 32, %i2
mov %g1, %i3
orcc %i2, %i3, %g0
be,pt %icc, .LL2
and %i5, %o5, %i5
sethi %hi(first_one), %g1
or %g1, %lo(first_one), %g1
ldub [%g1+%i3], %i0
.LL10:
return %i7+8
nop
.LL2:
orcc %i4, %i5, %g0
be,pt %icc, .LL5
sethi %hi(64512), %g1
sethi %hi(first_one), %g1
or %g1, %lo(first_one), %g1
ldub [%g1+%i5], %i5
ba,pt %xcc, .LL10
add %i5, 16, %i0
.LL5:
or %g1, 1023, %g1
and %i1, %g1, %i3
sllx %i0, 32, %g1
srl %i1, 0, %i1
or %i1, %g1, %g1
srlx %g1, 16, %g1
srlx %g1, 32, %i4
mov %g1, %i5
and %i4, %o4, %i0
and %i5, %o5, %i1
orcc %i0, %i1, %g0
be,pt %icc, .LL7
sethi %hi(first_one), %g1
or %g1, %lo(first_one), %g1
ldub [%g1+%i1], %i5
ba,pt %xcc, .LL10
add %i5, 32, %i0
.LL7:
or %g1, %lo(first_one), %g1
ldub [%g1+%i3], %i5
ba,pt %xcc, .LL10
add %i5, 48, %i0
.size FirstOne, .-FirstOne
.ident "GCC: (GNU) 3.5.0 20040710 (experimental)"
The next planned step is to allow multiple epilogues (at least when they are
trivial). This is currently blocked by a small code quality regression
introduced by the previous change in some cases.
> The function is from crafty, a different version of this function appears in
> 186.crafty from SPEC2000, the same problem can be seen in that code. (The code
> in SPEC2K, which is functionally equivalent is optimized much better than the
> function above).
Do you run SPEC2K regularly on SPARC machines?
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |ebotcazou at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16532
next prev parent reply other threads:[~2004-07-14 7:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-13 21:54 [Bug rtl-optimization/16532] New: duplicate function epilogue on sparc dann at godzilla dot ics dot uci dot edu
2004-07-13 22:31 ` [Bug target/16532] " pinskia at gcc dot gnu dot org
2004-07-14 7:29 ` [Bug target/16532] Inefficient jump to epilogue ebotcazou at gcc dot gnu dot org
2004-07-14 7:43 ` ebotcazou at gcc dot gnu dot org [this message]
2004-07-14 16:19 ` dann at godzilla dot ics dot uci dot edu
2004-08-18 18:30 ` dann at godzilla dot ics dot uci dot edu
2004-08-19 10:13 ` ebotcazou at gcc dot gnu dot org
2004-08-19 16:58 ` dann at godzilla dot ics dot uci dot edu
2004-09-27 20:35 ` pinskia at gcc dot gnu dot org
2004-09-28 6:26 ` cvs-commit at gcc dot gnu dot org
2004-09-28 6:34 ` ebotcazou at gcc dot gnu dot org
2004-09-28 6:57 ` ebotcazou at gcc dot gnu dot org
2004-09-28 7:00 ` ebotcazou at gcc dot gnu dot org
2004-09-28 7:14 ` ebotcazou at gcc dot gnu dot org
2004-09-28 7:17 ` ebotcazou at gcc dot gnu dot org
2004-09-28 7:18 ` ebotcazou at gcc dot gnu dot org
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