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From: "pthaugen at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/39976] [4.5 Regression] Big sixtrack degradation on powerpc 32/64 after revision r146817
Date: Wed, 08 Jul 2009 21:53:00 -0000 [thread overview]
Message-ID: <20090708215311.29026.qmail@sourceware.org> (raw)
In-Reply-To: <bug-39976-16550@http.gcc.gnu.org/bugzilla/>
------- Comment #20 from pthaugen at gcc dot gnu dot org 2009-07-08 21:53 -------
Created an attachment (id=18165)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18165&action=view)
Reduced testcase
The attatched testcase exhibits the problem with the load-hit-store. It's
resulting from choosing a bad register class (GENERAL_REGS) for a pseudo that
should get assigned to FLOAT_REGS. Since there is no FPR -> GPR move for
-mcpu=power6 the copy must go through memory. I compiled the testcase with
-m64 -O3 -mcpu=power6 using trunk revision 149376. The pseudo in question is
361.
Following are the 3 insns referencing reg 361 in the sched1 dump (before ira):
(insn 51 238 241 8 thin6d_reduced.f:178 (set (reg:DF 361 [ prephitmp.35 ])
(reg:DF 358 [ prephitmp.35 ])) 351 {*movdf_hardfloat64} (nil))
...
(insn 47 46 231 9 thin6d_reduced.f:178 (set (reg:DF 361 [ prephitmp.35 ])
(reg:DF 179 [ prephitmp.35 ])) 351 {*movdf_hardfloat64} (nil))
...
(insn 196 194 198 11 thin6d_reduced.f:169 (set (mem/c/i:DF (plus:DI (reg/f:DI
477)
(const_int 56 [0x38])) [2 crkve+0 S8 A64])
(reg:DF 361 [ prephitmp.35 ])) 351 {*movdf_hardfloat64}
(expr_list:REG_DEAD (reg:DF 361 [ prephitmp.35 ])
(nil)))
And from the ira dump:
Pass1 cost computation:
a71 (r361,l1) best GENERAL_REGS, cover GENERAL_REGS
a3 (r361,l0) best GENERAL_REGS, cover GENERAL_REGS
a3(r361,l0) costs: BASE_REGS:0,0 GENERAL_REGS:0,0 FLOAT_REGS:0,0
LINK_REGS:156,1836 CTR_REGS:156,1836 SPECIAL_REGS:156,1836 MEM:156
a71(r361,l1) costs: BASE_REGS:0,0 GENERAL_REGS:0,0 FLOAT_REGS:0,0
LINK_REGS:1680,1680 CTR_REGS:1680,1680 SPECIAL_REGS:1680,1680 MEM:1120
Pass 2 cost computation:
r361: preferred GENERAL_REGS, alternative NO_REGS
a3(r361,l0) costs: BASE_REGS:0,2240 GENERAL_REGS:0,2240 FLOAT_REGS:312,2552
LINK_REGS:234,4154 CTR_REGS:234,4154 SPECIAL_REGS:234,4154 MEM:156
a71(r361,l1) costs: BASE_REGS:2240,2240 GENERAL_REGS:2240,2240
FLOAT_REGS:2240,2240 LINK_REGS:3920,3920 CTR_REGS:3920,3920
SPECIAL_REGS:3920,3920 MEM:3360
Not sure what's causing the FLOAT cost to be higher than the GENERAL cost yet.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39976
next prev parent reply other threads:[~2009-07-08 21:53 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-30 16:25 [Bug regression/39976] New: " luisgpm at linux dot vnet dot ibm dot com
2009-04-30 16:57 ` [Bug middle-end/39976] " pinskia at gcc dot gnu dot org
2009-04-30 19:30 ` luisgpm at linux dot vnet dot ibm dot com
2009-04-30 19:39 ` luisgpm at linux dot vnet dot ibm dot com
2009-04-30 19:52 ` pinskia at gcc dot gnu dot org
2009-04-30 20:17 ` hjl dot tools at gmail dot com
2009-05-01 20:07 ` rguenth at gcc dot gnu dot org
2009-05-04 13:51 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-04 14:37 ` matz at gcc dot gnu dot org
2009-05-04 15:41 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-04 15:50 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-04 16:10 ` matz at gcc dot gnu dot org
2009-05-05 15:52 ` mmitchel at gcc dot gnu dot org
2009-05-12 12:56 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-12 13:38 ` matz at gcc dot gnu dot org
2009-05-12 15:29 ` pinskia at gcc dot gnu dot org
2009-05-13 18:17 ` matz at gcc dot gnu dot org
2009-05-13 20:15 ` matz at gcc dot gnu dot org
2009-05-14 4:12 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-15 2:16 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-15 2:19 ` luisgpm at linux dot vnet dot ibm dot com
2009-05-18 18:09 ` pthaugen at gcc dot gnu dot org
2009-05-21 10:40 ` rguenth at gcc dot gnu dot org
2009-06-03 3:01 ` luisgpm at linux dot vnet dot ibm dot com
2009-07-08 21:53 ` pthaugen at gcc dot gnu dot org [this message]
2009-07-09 10:43 ` matz at gcc dot gnu dot org
2009-07-14 21:15 ` pthaugen at gcc dot gnu dot org
2009-07-23 23:49 ` pthaugen at gcc dot gnu dot org
2009-11-30 13:14 ` rguenth at gcc dot gnu dot org
2009-11-30 21:29 ` pthaugen at gcc dot gnu dot org
2010-03-28 15:51 ` rguenth at gcc dot gnu dot org
2010-03-31 11:56 ` rguenth at gcc dot gnu dot org
2010-04-06 11:38 ` rguenth at gcc dot gnu dot org
2010-07-31 9:33 ` [Bug middle-end/39976] [4.5/4.6 " rguenth at gcc dot gnu dot org
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