On Wed, 2017-03-22 at 15:47 -0700, Francisco Jerez wrote: > Samuel Iglesias Gonsálvez <sigles...@igalia.com> writes: > > > Generalize it to lower any unsupported narrower conversion. > > > > v2 (Curro): > > - Add supports_type_conversion() > > - Reuse existing intruction instead of cloning it. > > - Generalize d2x to narrower and equal size conversions. > > > > Signed-off-by: Samuel Iglesias Gonsálvez <sigles...@igalia.com> > > --- > > src/intel/compiler/brw_fs.cpp | 11 ++-- > > src/intel/compiler/brw_fs_lower_d2x.cpp | 97 > > ++++++++++++++++++++++++--------- > > 2 files changed, 77 insertions(+), 31 deletions(-) > > > > diff --git a/src/intel/compiler/brw_fs.cpp > > b/src/intel/compiler/brw_fs.cpp > > index 6da23b17107..8612a83805d 100644 > > --- a/src/intel/compiler/brw_fs.cpp > > +++ b/src/intel/compiler/brw_fs.cpp > > @@ -5694,11 +5694,6 @@ fs_visitor::optimize() > > OPT(dead_code_eliminate); > > } > > > > - if (OPT(lower_d2x)) { > > - OPT(opt_copy_propagation); > > - OPT(dead_code_eliminate); > > - } > > - > > OPT(lower_simd_width); > > > > /* After SIMD lowering just in case we had to unroll the EOT > > send. */ > > @@ -5745,6 +5740,12 @@ fs_visitor::optimize() > > OPT(dead_code_eliminate); > > } > > > > + if (OPT(lower_d2x)) { > > + OPT(opt_copy_propagation); > > + OPT(dead_code_eliminate); > > + OPT(lower_simd_width); > > + } > > + > > lower_uniform_pull_constant_loads(); > > > > validate(); > > diff --git a/src/intel/compiler/brw_fs_lower_d2x.cpp > > b/src/intel/compiler/brw_fs_lower_d2x.cpp > > index a2db1154615..fa25d313dcd 100644 > > --- a/src/intel/compiler/brw_fs_lower_d2x.cpp > > +++ b/src/intel/compiler/brw_fs_lower_d2x.cpp > > @@ -27,47 +27,92 @@ > > > > using namespace brw; > > > > +static bool > > +supports_type_conversion(fs_inst *inst) { > > Pointer should be marked const. > > > + switch(inst->opcode) { > > + case BRW_OPCODE_MOV: > > + case SHADER_OPCODE_MOV_INDIRECT: > > + return true; > > + case BRW_OPCODE_SEL: > > + return false; > > I suggest you return 'inst->dst.type == get_exec_type_size(inst)' > here > in order to simplify the logic below and restructure things in a way > that allows you to make opcode-specific decisions here based on the > actual execution and destination types.
I guess you meant: 'type_sz(inst->dst.type) == get_exec_type_size(inst)' This would make it simpler but we then allow f2d conversion which is not allowed for SEL. > > > + default: > > + /* FIXME: We assume the opcodes don't explicitly mentioned > > + * before just work fine with arbitrary conversions. > > + */ > > + return true; > > + } > > +} > > + > > bool > > fs_visitor::lower_d2x() > > { > > bool progress = false; > > > > foreach_block_and_inst_safe(block, fs_inst, inst, cfg) { > > - if (inst->opcode != BRW_OPCODE_MOV) > > - continue; > > + bool inst_support_conversion = > > supports_type_conversion(inst); > > + bool supported_conversion = > > + inst_support_conversion && > > + (get_exec_type_size(inst) != 8 || > > + type_sz(inst->dst.type) > 4 || > > + type_sz(inst->dst.type) >= get_exec_type_size(inst)); > > > > - if (inst->dst.type != BRW_REGISTER_TYPE_F && > > - inst->dst.type != BRW_REGISTER_TYPE_D && > > - inst->dst.type != BRW_REGISTER_TYPE_UD) > > + /* If the conversion is supported or there is no conversion > > then > > + * do nothing. > > + */ > > + if (supported_conversion || > > + (!inst_support_conversion && inst->dst.type == inst- > > >src[0].type) || > > You should be using the execution type here (and below where you > allocate the temp0 and temp1 vgrfs) instead of assuming it matches > the > type of the first source. Also I'm not 100% certain that the > combination of this conditional continue, the one below, the if/else > branches below and the supported_conversion definitions above catch > the > exact set of cases where you need to apply lowering. This would be a > lot easier to follow (most of the above goes away) if you did > something > along the lines of: > OK, thanks. > > if (supports_type_conversion(inst)) { > > if (get_exec_type_size(inst) == 8 && type_sz(inst->dst.type) < > > 8) { > > // Apply strided move workaround... > > progress = true; > > } > > } else { > > // Apply general conversion workaround... > > progress = true; > > } > > + inst->dst.file == BAD_FILE || inst->src[0].file == > > BAD_FILE) > > I don't think the 'inst->dst.file == BAD_FILE || inst->src[0].file == > BAD_FILE' terms of this expression are correct or useful, the > 'inst->src[0].file' term because there might be a destination region > conversion regardless of what the file of the first source is, the > 'inst->dst.file == BAD_FILE' term because you could just rely on DCE > instead... > OK > > continue; > > > > - if (inst->src[0].type != BRW_REGISTER_TYPE_DF && > > - inst->src[0].type != BRW_REGISTER_TYPE_UQ && > > - inst->src[0].type != BRW_REGISTER_TYPE_Q) > > - continue; > > + /* This pass only supports conversion to narrower or equal > > size types. */ > > + if (get_exec_type_size(inst) < type_sz(inst->dst.type)) > > + continue; > > > > I think you need to apply this condition to the if branch below that > deals with DF to F conversions *only*, the else branch you probably > need > to apply regardless of whether the destination type is larger or > smaller > than the execution type. > OK > > - assert(inst->dst.file == VGRF); > > assert(inst->saturate == false); > > I don't see why it's safe to rely on saturate being false here, in > any > case it would be straightforward to handle it by setting the flag on > the > emitted MOV instruction and clearing it on the original instruction. > OK > > - fs_reg dst = inst->dst; > > > > const fs_builder ibld(this, block, inst); > > + fs_reg dst = inst->dst; > > > > - /* From the Broadwell PRM, 3D Media GPGPU, "Double Precision > > Float to > > - * Single Precision Float": > > - * > > - * The upper Dword of every Qword will be written with > > undefined > > - * value when converting DF to F. > > - * > > - * So we need to allocate a temporary that's two registers, > > and then do > > - * a strided MOV to get the lower DWord of every Qword that > > has the > > - * result. > > - */ > > - fs_reg temp = ibld.vgrf(inst->src[0].type, 1); > > - fs_reg strided_temp = subscript(temp, inst->dst.type, 0); > > - ibld.MOV(strided_temp, inst->src[0]); > > - ibld.MOV(dst, strided_temp); > > + if (inst_support_conversion && !supported_conversion) { > > + /* From the Broadwell PRM, 3D Media GPGPU, "Double > > Precision Float to > > + * Single Precision Float": > > + * > > + * The upper Dword of every Qword will be written with > > undefined > > + * value when converting DF to F. > > + * > > + * So we need to allocate a temporary that's two > > registers, and then do > > + * a strided MOV to get the lower DWord of every Qword > > that has the > > + * result. > > + */ > > + fs_reg temp = ibld.vgrf(inst->src[0].type, 1); > > The '1' argument is redundant in all fs_builder::vgrf() calls here > and > below. > OK > > + fs_reg strided_temp = subscript(temp, dst.type, 0); > > + > > + /* We clone the original instruction as we are going to > > modify it > > + * and emit another one after it. > > + */ > > Comment seems stale. > Right. > > + inst->dst = strided_temp; > > + /* As it is an strided destination, we write n-times more > > being n the > > + * size difference between source and destination types. > > Update > > I guess by difference you meant ratio here and in the copy-pasted > comment below (the comments also have a few minor spelling mistakes > but > that's unlikely to cause as much confusion). > Right. > > + * size_written with the new destination. > > + */ > > + inst->size_written = inst->dst.component_size(inst- > > >exec_size); > > I think I'd add an assert(inst->size_written == > inst->dst.component_size(inst->exec_size)) right before you assign > 'inst->dst' to point at the temporary in order to make sure you > aren't > accidentally miscompiling instructions that write multiple > components. > OK > > + ibld.at(block, inst->next).MOV(dst, strided_temp); > > + } else { > > + fs_reg temp0 = ibld.vgrf(inst->src[0].type, 1); > > + fs_reg temp1 = ibld.vgrf(inst->src[0].type, 1); > > + fs_reg strided_temp1 = subscript(temp1, dst.type, 0); > > + > > + inst->dst = temp0; > > + /* As it is an strided destination, we write n-times more > > being n the > > + * size difference between source and destination types. > > Update > > + * size_written with the new destination. > > + */ > > + inst->size_written = inst->dst.component_size(inst- > > >exec_size); > > > > - inst->remove(block); > > + /* Now, do the conversion to original destination's type. > > */ > > + fs_inst *mov = ibld.at(block, inst- > > >next).MOV(strided_temp1, temp0); > > + ibld.at(block, mov->next).MOV(dst, strided_temp1); > > Isn't this MOV and the strided_temp1 handling redundant? I'd expect > it > to be handled automatically during the next loop iteration of this > pass > (though you may have to switch back to foreach_block_and_inst() > instead > of foreach_block_and_inst_safe()), which would also result in better > code because the extra move would only be emitted if this is an > actual > DF->F conversion. > Good catch! Thanks for all the suggestions, I am going to do them. Sam > > + } > > progress = true; > > } > > > > -- > > 2.11.0 > > > > _______________________________________________ > > mesa-dev mailing list > > mesa-dev@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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