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Commit 1f862e92 authored by Matt Turner's avatar Matt Turner
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i965/fs: Optimize float conversions of byte/word extract.


   instructions in affected programs: 31535 -> 29966 (-4.98%)
   helped: 23

   cycles in affected programs: 272648 -> 266022 (-2.43%)
   helped: 14
   HURT: 1

The patch decreases the number of instructions in the two Unigine
programs by:

 #1721: 4374 -> 4155 instructions (-5.01%)
 #1706: 3582 -> 3363 instructions (-6.11%)

Reviewed-by: Kenneth Graunke's avatarKenneth Graunke <kenneth@whitecape.org>
Reviewed-by: default avatarIago Toral Quiroga <itoral@igalia.com>
parent 905ff861
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......@@ -272,6 +272,8 @@ public:
void emit_percomp(const brw::fs_builder &bld, const fs_inst &inst,
unsigned wr_mask);
bool optimize_extract_to_float(nir_alu_instr *instr,
const fs_reg &result);
bool optimize_frontfacing_ternary(nir_alu_instr *instr,
const fs_reg &result);
......
......@@ -500,6 +500,49 @@ fs_visitor::nir_emit_instr(nir_instr *instr)
}
}
/**
* Recognizes a parent instruction of nir_op_extract_* and changes the type to
* match instr.
*/
bool
fs_visitor::optimize_extract_to_float(nir_alu_instr *instr,
const fs_reg &result)
{
if (!instr->src[0].src.is_ssa ||
!instr->src[0].src.ssa->parent_instr)
return false;
if (instr->src[0].src.ssa->parent_instr->type != nir_instr_type_alu)
return false;
nir_alu_instr *src0 =
nir_instr_as_alu(instr->src[0].src.ssa->parent_instr);
if (src0->op != nir_op_extract_u8 && src0->op != nir_op_extract_u16 &&
src0->op != nir_op_extract_i8 && src0->op != nir_op_extract_i16)
return false;
nir_const_value *element = nir_src_as_const_value(src0->src[1].src);
assert(element != NULL);
enum opcode extract_op;
if (src0->op == nir_op_extract_u16 || src0->op == nir_op_extract_i16) {
assert(element->u[0] <= 1);
extract_op = SHADER_OPCODE_EXTRACT_WORD;
} else {
assert(element->u[0] <= 3);
extract_op = SHADER_OPCODE_EXTRACT_BYTE;
}
fs_reg op0 = get_nir_src(src0->src[0].src);
op0.type = brw_type_for_nir_type(nir_op_infos[src0->op].input_types[0]);
op0 = offset(op0, bld, src0->src[0].swizzle[0]);
set_saturate(instr->dest.saturate,
bld.emit(extract_op, result, op0, brw_imm_ud(element->u[0])));
return true;
}
bool
fs_visitor::optimize_frontfacing_ternary(nir_alu_instr *instr,
const fs_reg &result)
......@@ -671,6 +714,9 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
switch (instr->op) {
case nir_op_i2f:
case nir_op_u2f:
if (optimize_extract_to_float(instr, result))
return;
inst = bld.MOV(result, op[0]);
inst->saturate = instr->dest.saturate;
break;
......
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