On Tue, 2016-05-03 at 17:28 -0700, Jordan Justen wrote:
> On 2016-05-03 05:21:55, Samuel Iglesias Gonsálvez wrote:
> > From: Iago Toral Quiroga <ito...@igalia.com>
> >
> > We were not accounting for reg_suboffset in the check for the start
> > of the region. This meant that would allow copy-propagation even if
> > the dst wrote to sub_regoffset 4 and our source read from
> > sub_regoffset 0, which is not correct. This was observed in fp64 code,
> > since there we use reg_suboffset to select the high 32-bit of a double.
> >
> > Also, fs_reg::regs_read() already takes the stride into account, so we
> > should not multiply its result by the stride again. This was making
> > copy-propagation fail to copy-propagate cases that would otherwise be
> > safe to copy-propagate. Again, this was observed in fp64 code, since
> > there we use stride > 1 often.
> >
> > Incidentally, these fixes open up more possibilities for copy propagation
> > which uncovered new bugs in copy-propagation. The folowing patches address
> > each of these new issues.
>
> Should this be moved after those fixes?
Yeah, I think that would be better.
> -Jordan
>
> > ---
> > .../drivers/dri/i965/brw_fs_copy_propagation.cpp | 21
> > +++++++++++++--------
> > 1 file changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> > b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> > index 5fae10f..23df877 100644
> > --- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> > +++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> > @@ -329,6 +329,15 @@ can_take_stride(fs_inst *inst, unsigned arg, unsigned
> > stride,
> > return true;
> > }
> >
> > +static inline bool
> > +region_match(fs_reg src, unsigned regs_read,
> > + fs_reg dst, unsigned regs_written)
> > +{
> > + return src.reg_offset >= dst.reg_offset &&
> > + (src.reg_offset + regs_read) <= (dst.reg_offset + regs_written)
> > &&
> > + src.subreg_offset >= dst.subreg_offset;
> > +}
> > +
> > bool
> > fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
> > {
> > @@ -351,10 +360,8 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg,
> > acp_entry *entry)
> > /* Bail if inst is reading a range that isn't contained in the range
> > * that entry is writing.
> > */
> > - if (inst->src[arg].reg_offset < entry->dst.reg_offset ||
> > - (inst->src[arg].reg_offset * 32 + inst->src[arg].subreg_offset +
> > - inst->regs_read(arg) * inst->src[arg].stride * 32) >
> > - (entry->dst.reg_offset + entry->regs_written) * 32)
> > + if (!region_match(inst->src[arg], inst->regs_read(arg),
> > + entry->dst, entry->regs_written))
> > return false;
> >
> > /* we can't generally copy-propagate UD negations because we
> > @@ -554,10 +561,8 @@ fs_visitor::try_constant_propagate(fs_inst *inst,
> > acp_entry *entry)
> > /* Bail if inst is reading a range that isn't contained in the range
> > * that entry is writing.
> > */
> > - if (inst->src[i].reg_offset < entry->dst.reg_offset ||
> > - (inst->src[i].reg_offset * 32 + inst->src[i].subreg_offset +
> > - inst->regs_read(i) * inst->src[i].stride * 32) >
> > - (entry->dst.reg_offset + entry->regs_written) * 32)
> > + if (!region_match(inst->src[i], inst->regs_read(i),
> > + entry->dst, entry->regs_written))
> > continue;
> >
> > fs_reg val = entry->src;
> > --
> > 2.5.0
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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