[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" <gcc-bugzilla at gcc dot gnu dot org>]

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