[Bug rtl-optimization/61559] New: FAIL: gcc.dg/builtin-bswap-8.c on i686 with -mmovbe

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61559

            Bug ID: 61559
           Summary: FAIL: gcc.dg/builtin-bswap-8.c on i686 with -mmovbe
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ubizjak at gmail dot com
            Target: i686-pc-linux-gnu

gcc.dg/builtin-bswap-8.c fails on i686 with -mmovbe:

~/gcc-build/gcc/cc1 -O2 -march=corei7 -mmovbe -m32 builtin-bswap-8.c

foo5:
        movbe   4(%esp), %eax
        movbe   8(%esp), %edx
        andl    %edx, %eax
        bswap   %eax
        ret
foo6:
        movbe   4(%esp), %eax
        movbe   8(%esp), %edx
        orl     %edx, %eax
        bswap   %eax
        ret
foo7:
        movbe   4(%esp), %eax
        movbe   8(%esp), %edx
        xorl    %edx, %eax
        bswap   %eax
        ret

It looks that direct swap from memory (movbe) interferes with bswap
elimination. Without -mmovbe, following asm is produced:

foo5:
        movl    8(%esp), %eax
        andl    4(%esp), %eax
        ret
foo6:
        movl    8(%esp), %eax
        orl     4(%esp), %eax
        ret
foo7:
        movl    8(%esp), %eax
        xorl    4(%esp), %eax
        ret