[commit, spu] Re: [BUILDROBOT] spu: left shift of negative value

[Ulrich Weigand]

Jan-Benedict Glaw wrote:

> I just noticed that (for config_list.mk builds), current GCC errors
> out at spu.c, see eg. build
> http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=3D469639 :
> 
> g++ -fno-PIE -c   -g -O2 -DIN_GCC  -DCROSS_DIRECTORY_STRUCTURE   -fno-excep=
> tions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrit=
> e-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -peda=
> ntic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -f=
> no-common  -DHAVE_CONFIG_H -I. -I. -I../../../gcc/gcc -I../../../gcc/gcc/. =
> -I../../../gcc/gcc/../include -I../../../gcc/gcc/../libcpp/include -I/opt/c=
> farm/mpc/include  -I../../../gcc/gcc/../libdecnumber -I../../../gcc/gcc/../=
> libdecnumber/dpd -I../libdecnumber -I../../../gcc/gcc/../libbacktrace   -o =
> spu.o -MT spu.o -MMD -MP -MF ./.deps/spu.TPo ../../../gcc/gcc/config/spu/sp=
> u.c
> ../../../gcc/gcc/config/spu/spu.c: In function =E2=80=98void spu_expand_ins=
> v(rtx_def**)=E2=80=99:
> ../../../gcc/gcc/config/spu/spu.c:530:46: error: left shift of negative val=
> ue [-Werror=3Dshift-negative-value]
>        maskbits =3D (-1ll << (32 - width - start));
>                                               ^
> ../../../gcc/gcc/config/spu/spu.c:536:46: error: left shift of negative val=
> ue [-Werror=3Dshift-negative-value]
>        maskbits =3D (-1ll << (64 - width - start));
>                                               ^
> cc1plus: all warnings being treated as errors
> Makefile:2092: recipe for target 'spu.o' failed
> make[2]: *** [spu.o] Error 1
> make[2]: Leaving directory '/home/jbglaw/build-configlist_mk/spu-elf/build-=
> gcc/mk/spu-elf/gcc'

I've now checked in the following fix.

Thanks,
Ulrich


ChangeLog:

        * config/spu/spu.c (spu_expand_insv): Avoid undefined behavior.

Index: gcc/config/spu/spu.c
===================================================================
*** gcc/config/spu/spu.c        (revision 227968)
--- gcc/config/spu/spu.c        (working copy)
*************** spu_expand_insv (rtx ops[])
*** 472,478 ****
  {
    HOST_WIDE_INT width = INTVAL (ops[1]);
    HOST_WIDE_INT start = INTVAL (ops[2]);
!   HOST_WIDE_INT maskbits;
    machine_mode dst_mode;
    rtx dst = ops[0], src = ops[3];
    int dst_size;
--- 472,478 ----
  {
    HOST_WIDE_INT width = INTVAL (ops[1]);
    HOST_WIDE_INT start = INTVAL (ops[2]);
!   unsigned HOST_WIDE_INT maskbits;
    machine_mode dst_mode;
    rtx dst = ops[0], src = ops[3];
    int dst_size;
*************** spu_expand_insv (rtx ops[])
*** 527,541 ****
    switch (dst_size)
      {
      case 32:
!       maskbits = (-1ll << (32 - width - start));
        if (start)
!       maskbits += (1ll << (32 - start));
        emit_move_insn (mask, GEN_INT (maskbits));
        break;
      case 64:
!       maskbits = (-1ll << (64 - width - start));
        if (start)
!       maskbits += (1ll << (64 - start));
        emit_move_insn (mask, GEN_INT (maskbits));
        break;
      case 128:
--- 527,541 ----
    switch (dst_size)
      {
      case 32:
!       maskbits = (~(unsigned HOST_WIDE_INT)0 << (32 - width - start));
        if (start)
!       maskbits += ((unsigned HOST_WIDE_INT)1 << (32 - start));
        emit_move_insn (mask, GEN_INT (maskbits));
        break;
      case 64:
!       maskbits = (~(unsigned HOST_WIDE_INT)0 << (64 - width - start));
        if (start)
!       maskbits += ((unsigned HOST_WIDE_INT)1 << (64 - start));
        emit_move_insn (mask, GEN_INT (maskbits));
        break;
      case 128:


-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  ulrich.weig...@de.ibm.com