[Bug target/52421] New: SH Target: -fnon-call-exceptions prevents delay slot filling

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52421

             Bug #: 52421
           Summary: SH Target: -fnon-call-exceptions prevents delay slot
                    filling
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: olegendo@gcc.gnu.org
            Target: sh*-*-*


When the -fnon-call-exceptions option is used delay slots might not be filled,
although they could.

int test (int x, int y)
{
  return x == y;
}

compiled with -Os:
    cmp/eq    r5,r4    ! 7    cmpeqsi_t/3    [length = 2]
    rts        ! 22    *return_i    [length = 2]
    movt    r0    ! 13    movsi_i/8    [length = 2]

compiled with -Os -fnon-call-exceptions
    cmp/eq    r5,r4    ! 7    cmpeqsi_t/3    [length = 2]
    movt    r0    ! 14    movsi_i/8    [length = 2]
    rts    
    nop    ! 24    *return_i    [length = 4]

It seems this happens for all SH variants.
When compiled for SH2A the no-delay-slot-rts insn is picked:
    cmp/eq    r5,r4    ! 7    cmpeqsi_t/3    [length = 2]
    movt    r0    ! 14    movsi_ie/10    [length = 2]
    rts/n    ! 28    *return_i    [length = 4]



Using built-in specs.
COLLECT_GCC=sh-elf-gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/sh-elf/4.7.0/lto-wrapper
Target: sh-elf
Configured with: ../gcc-trunk/configure --target=sh-elf --prefix=/usr/local
--enable-languages=c,c++ --enable-multilib --disable-libssp --disable-nls
--disable-werror --enable-lto --with-newlib --with-gnu-as --with-gnu-ld
--with-system-zlib
Thread model: single
gcc version 4.7.0 20120227 (experimental) (GCC)