[Bug rtl-optimization/49080] New: Wrong register allocation for even register

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49080

           Summary: Wrong register allocation for even register
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Keywords: ra, wrong-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: rgue...@gcc.gnu.org
                CC: vmaka...@gcc.gnu.org, kreb...@gcc.gnu.org
            Target: s390-linux


Created attachment 24300
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24300
preprocessed source

glibc _itoa is miscompiled with

> ./cc1 -quiet -fpreprocessed _itoa.i -quiet -dumpbase _itoa.c -m31 -mesa -O2 
> -std=gnu99 -fgnu89-inline -fmerge-all-constants -fno-strict-aliasing -fpic -o 
> _itoa.s -march=z10 -mzarch -mtune=z196

(reproduced on a x86_64 -> s390-linux cross)

resulting in SIGILLs because mr needs an even numbered register as first
operand.

_itoa:
.LFB5:
        stm     %r6,%r15,24(%r15)
.LCFI8:
...
#APP
# 434 "_itoa.c" 1
        lr %r14,%r1
        mr %r13,%r10
#NO_APP
        nr      %r3,%r14