[Bug rtl-optimization/46843] New: ICE: in spill_failure, at reload1.c:2157 -fschedule-insns -fsched-pressure when using doubles

[Bug rtl-optimization/46843] New: ICE: in spill_failure, at reload1.c:2157 -fschedule-insns -fsched-pressure when using doubles

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46843

           Summary: ICE: in spill_failure, at reload1.c:2157
                    -fschedule-insns -fsched-pressure when using doubles
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 22677
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22677
reduced testcase

Compiler output:
$ gcc -O -fschedule-insns -fsched-pressure pr46843.c 
pr46843.c: In function 'foo':
pr46843.c:9:1: error: unable to find a register to spill in class 'CREG'
pr46843.c:9:1: error: this is the insn:
(insn 19 50 9 2 (parallel [
            (set (reg/v:SI 0 ax [orig:63 n ] [63])
                (ashift:SI (reg:SI 0 ax [84])
                    (reg:QI 37 r8 [ s ])))
            (clobber (reg:CC 17 flags))
        ]) pr46843.c:3 497 {*ashlsi3_1}
     (expr_list:REG_DEAD (reg:SI 0 ax [84])
        (expr_list:REG_DEAD (reg:QI 37 r8 [ s ])
            (expr_list:REG_UNUSED (reg:CC 17 flags)
                (nil)))))
pr46843.c:9:1: internal compiler error: in spill_failure, at reload1.c:2105
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

-mdispatch-scheduler -march=bdver1 doesn't help in this case (opposing to
PR46829)

Tested revisions:
r167471 - fail
4.5 r166509 - fail

[Bug rtl-optimization/46843] ICE: in spill_failure, at reload1.c:2157 -fschedule-insns -fsched-pressure

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46843

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-07-13
   Target Milestone|---                         |4.6.4
            Summary|ICE: in spill_failure, at   |ICE: in spill_failure, at
                   |reload1.c:2157              |reload1.c:2157
                   |-fschedule-insns            |-fschedule-insns
                   |-fsched-pressure when using |-fsched-pressure
                   |doubles                     |
     Ever Confirmed|0                           |1
      Known to fail|                            |4.7.2, 4.8.0

--- Comment #1 from Uros Bizjak <ubizjak at gmail dot com> 2012-07-13 15:07:28 UTC ---
Confirmed.

sched1 pass is moving insn that reads CX hard register after the shift:

(insn 20 7 10 2 (parallel [
            (set (reg/v:SI 64 [ n ])
                (ashift:SI (reg:SI 85)
                    (reg:QI 37 r8 [ s ])))
            (clobber (reg:CC 17 flags))
        ]) pr46843.c:3 498 {*ashlsi3_1}
     (expr_list:REG_DEAD (reg:SI 85)
        (expr_list:REG_DEAD (reg:QI 37 r8 [ s ])
            (expr_list:REG_UNUSED (reg:CC 17 flags)
                (nil)))))

(insn 10 20 13 2 (set (reg/v/f:DI 81 [ d2 ])
        (reg:DI 2 cx [ d2 ])) pr46843.c:2 63 {*movdi_internal_rex64}
     (expr_list:REG_DEAD (reg:DI 2 cx [ d2 ])
        (nil)))

Probably not a good idea to increase live ranges of hard registers before
register allocation pass.

This PR is somehow related to PR 53942, where combine pass increased live range
of CX register after shift insn.

[Bug rtl-optimization/46843] ICE: in spill_failure, at reload1.c:2157 -fschedule-insns -fsched-pressure

[uros at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46843

--- Comment #2 from uros at gcc dot gnu.org 2012-09-01 14:29:51 UTC ---
Author: uros
Date: Sat Sep  1 14:29:45 2012
New Revision: 190847

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190847
Log:
    PR target/46829
    PR target/46843
    * config/i386/i386.c (ix86_legitimate_combined_insn): New function.
    (TARGET_LEGITIMATE_COMBINED_INSN): New macro.

testsuite/ChangeLog:

    PR target/46829
    PR target/46843
    * gcc.target/i386/pr46829.c: New test.
    * gcc.target/i386/pr46843.c: Ditto.


Added:
    trunk/gcc/testsuite/gcc.target/i386/pr46829.c
    trunk/gcc/testsuite/gcc.target/i386/pr46843.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/46843] ICE: in spill_failure, at reload1.c:2157 -fschedule-insns -fsched-pressure

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46843

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.6.4                       |4.8.0
      Known to fail|4.8.0                       |

--- Comment #3 from Uros Bizjak <ubizjak at gmail dot com> 2012-09-05 08:16:32 UTC ---
Fixed for 4.8.