[Bug c/34845] New: [4.3.0 20080111] mips16 : branch in branch delay slot

[Bug c/34845] New: [4.3.0 20080111] mips16 : branch in branch delay slot

[armcc2000 at yahoo dot com]

$ mipsel-linux-gnu-gcc -v
Using built-in specs.
Target: mipsel-linux-gnu
Configured with:
/home/andre/toolchain/bs_build_4.3-20080111/gcc-4.3-20080111/configure
--prefix=/usr/local/mipsel_amd64/4.3-20080111-bare --target=mipsel-linux-gnu
--enable-languages=c --enable-checking=no --with-gnu-as --with-gnu-ld
--with-newlib --disable-libada --disable-libgomp --disable-libssp --disable-nls
--disable-multilib --disable-shared --disable-threads --with-tune=mips32r2
--with-gmp=/usr/local/mipsel_amd64/4.3-20080111-bare
--with-mpfr=/usr/local/mipsel_amd64/4.3-20080111-bare
Thread model: single
gcc version 4.3.0 20080111 (experimental) (GCC) 

$ cat badmips16.c

void foo (unsigned long base, unsigned char *dst, unsigned int count)
{
        while (count && ((unsigned long) dst) & 0x03) {
                count--;
                *dst++ = *((volatile unsigned char *) base);
        }               
        while (count >= 4) {
                count -= 4;
                *dst = *((volatile unsigned int *) base);
                dst += 4;
        }
}

$ mipsel-linux-gnu-gcc -Os -mips16 -march=mips32r2 -mno-abicalls -c badmips16.c
$ mipsel-linux-gnu-objdump -d badmips16.o

badmips16.o:     file format elf32-tradlittlemips

Disassembly of section .text:

00000000 <foo>:
   0:   1004            b       a <foo+0xa>
   2:   a440            lbu     v0,0(a0)
   4:   4eff            addiu   a2,-1
   6:   c540            sb      v0,0(a1)
   8:   4d01            addiu   a1,1
   a:   2608            beqz    a2,1c <foo+0x1c>
   c:   6a03            li      v0,3
   e:   eaac            and     v0,a1
  10:   2af8            bnez    v0,2 <foo+0x2>
  12:   1004            b       1c <foo+0x1c>
  14:   9c40            lw      v0,0(a0)
  16:   4efc            addiu   a2,-4
  18:   c540            sb      v0,0(a1)
  1a:   4d04            addiu   a1,4
  1c:   5e04            sltiu   a2,4
  1e:   60fa            bteqz   14 <foo+0x14>
  20:   e8a0            jrc     ra
  22:   6500            nop
  ...
  ...

Bug: The branch instruction at offset 0x12 is in the branch delay slot of the
bnez instruction at offset 0x10.


-- 
           Summary: [4.3.0 20080111] mips16 : branch in branch delay slot
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: armcc2000 at yahoo dot com
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: mipsel-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34845

[Bug rtl-optimization/34845] [4.3.0 20080111] mips16 : branch in branch delay slot

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
           Severity|major                       |normal
          Component|c                           |rtl-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34845

[Bug rtl-optimization/34845] [4.3.0 20080111] mips16 : branch in branch delay slot

[armcc2000 at yahoo dot com]

------- Comment #1 from armcc2000 at yahoo dot com  2008-01-18 03:57 -------
Bug is invalid: branches in mips16 don't have delay slots. The cause of the
problems I was seeing was found elsewhere. Sorry for the noise...


-- 

armcc2000 at yahoo dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34845