On Tue, 18 Dec 2018 03:08:51 -0600
Segher Boessenkool <seg...@kernel.crashing.org> wrote:
> Hi!
>
> On Fri, Dec 14, 2018 at 03:22:13PM +0000, Jozef Lawrynowicz wrote:
> > 2018-12-14 Jozef Lawrynowicz <joze...@mittosystems.com>
> >
> > gcc/ChangeLog:
> > * combine.c (update_rsp_from_reg_equal): Only look for the nonzero bits
> > of src in nonzero_bits_mode if the mode of src is MODE_INT and
> > HWI_COMPUTABLE.
> > (reg_nonzero_bits_for_combine): Add clarification to comment.
>
> Is there some PR this fixes?
No not for this one, I just spotted the timeouts in the GCC testsuite.
> >
> > diff --git a/gcc/combine.c b/gcc/combine.c
> > index 7e61139..c93aaed 100644
> > --- a/gcc/combine.c
> > +++ b/gcc/combine.c
> > @@ -1698,9 +1698,13 @@ update_rsp_from_reg_equal (reg_stat_type *rsp,
> > rtx_insn *insn, const_rtx set,
> > /* Don't call nonzero_bits if it cannot change anything. */
> > if (rsp->nonzero_bits != HOST_WIDE_INT_M1U)
> > {
> > - bits = nonzero_bits (src, nonzero_bits_mode);
> > + machine_mode mode = GET_MODE (x);
> > + if (GET_MODE_CLASS (mode) == MODE_INT
> > + && HWI_COMPUTABLE_MODE_P (mode))
> > + mode = nonzero_bits_mode;
> > + bits = nonzero_bits (src, mode);
> > if (reg_equal && bits)
> > - bits &= nonzero_bits (reg_equal, nonzero_bits_mode);
> > + bits &= nonzero_bits (reg_equal, mode);
> > rsp->nonzero_bits |= bits;
> > }
> >
> > @@ -10224,6 +10228,7 @@ simplify_and_const_int (rtx x, scalar_int_mode
> > mode, rtx varop,
> >
> > /* Given a REG X of mode XMODE, compute which bits in X can be nonzero.
> > We don't care about bits outside of those defined in MODE.
> > + We DO care about all the bits in MODE, even if XMODE is smaller than
> > MODE.
> >
> > For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
> > a shift, AND, or zero_extract, we can do better. */
>
> I think this is okay for trunk, and for backports after waiting a week
> or so for fallout. Thanks!
Thanks, applied to trunk.
Jozef
