KonstantinSeurer
/
mesa
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

glsl: Add lowering pass for ir_quadop_bitfield_insert 

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This commit is contained in:
Ian Romanick 2016-06-23 23:16:10 -07:00
parent 4d6d219b58
commit 3079dcb00c
2 changed files with 74 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/compiler/glsl/ir_optimization.h
View File

@ -44,6 +44,7 @@
#define DFREXP_DLDEXP_TO_ARITH 0x1000
#define BIT_COUNT_TO_MATH 0x02000
#define EXTRACT_TO_SHIFTS 0x04000
#define INSERT_TO_SHIFTS 0x08000
/**
* \see class lower_packing_builtins_visitor

73
src/compiler/glsl/lower_instructions.cpp
View File

@ -161,6 +161,7 @@ private:
void dsign_to_csel(ir_expression *);
void bit_count_to_math(ir_expression *);
void extract_to_shifts(ir_expression *);
void insert_to_shifts(ir_expression *);
};
} /* anonymous namespace */
@ -1076,6 +1077,72 @@ lower_instructions_visitor::extract_to_shifts(ir_expression *ir)
this->progress = true;
}
void
lower_instructions_visitor::insert_to_shifts(ir_expression *ir)
{
ir_constant *c1;
ir_constant *c32;
ir_constant *cFFFFFFFF;
ir_variable *offset =
new(ir) ir_variable(ir->operands[0]->type, "offset", ir_var_temporary);
ir_variable *bits =
new(ir) ir_variable(ir->operands[0]->type, "bits", ir_var_temporary);
ir_variable *mask =
new(ir) ir_variable(ir->operands[0]->type, "mask", ir_var_temporary);
if (ir->operands[0]->type->base_type == GLSL_TYPE_INT) {
c1 = new(ir) ir_constant(int(1), ir->operands[0]->type->vector_elements);
c32 = new(ir) ir_constant(int(32), ir->operands[0]->type->vector_elements);
cFFFFFFFF = new(ir) ir_constant(int(0xFFFFFFFF), ir->operands[0]->type->vector_elements);
} else {
assert(ir->operands[0]->type->base_type == GLSL_TYPE_UINT);
c1 = new(ir) ir_constant(1u, ir->operands[0]->type->vector_elements);
c32 = new(ir) ir_constant(32u, ir->operands[0]->type->vector_elements);
cFFFFFFFF = new(ir) ir_constant(0xFFFFFFFFu, ir->operands[0]->type->vector_elements);
}
base_ir->insert_before(offset);
base_ir->insert_before(assign(offset, ir->operands[2]));
base_ir->insert_before(bits);
base_ir->insert_before(assign(bits, ir->operands[3]));
/* At least some hardware treats (x << y) as (x << (y%32)). This means
* we'd get a mask of 0 when bits is 32. Special case it.
*
* mask = (bits == 32 ? 0xffffffff : (1u << bits) - 1u) << offset;
*
* Section 8.8 (Integer Functions) of the GLSL 4.50 spec says:
*
* The result will be undefined if offset or bits is negative, or if the
* sum of offset and bits is greater than the number of bits used to
* store the operand.
*
* Since it's undefined, there are a couple other ways this could be
* implemented. The other way that was considered was to put the csel
* around the whole thing:
*
* final_result = bits == 32 ? insert : ... ;
*/
base_ir->insert_before(mask);
base_ir->insert_before(assign(mask, csel(equal(bits, c32),
cFFFFFFFF,
lshift(sub(lshift(c1, bits),
c1->clone(ir, NULL)),
offset))));
/* (base & ~mask) | ((insert << offset) & mask) */
ir->operation = ir_binop_bit_or;
ir->operands[0] = bit_and(ir->operands[0], bit_not(mask));
ir->operands[1] = bit_and(lshift(ir->operands[1], offset), mask);
ir->operands[2] = NULL;
ir->operands[3] = NULL;
this->progress = true;
}
ir_visitor_status
lower_instructions_visitor::visit_leave(ir_expression *ir)
{
@ -1188,6 +1255,12 @@ lower_instructions_visitor::visit_leave(ir_expression *ir)
extract_to_shifts(ir);
break;
case ir_quadop_bitfield_insert:
if (lowering(INSERT_TO_SHIFTS))
insert_to_shifts(ir);
break;
default:
return visit_continue;
}