fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-05-05 09:38:07 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

mesa/st: don't use CMP / I2F for conditional assignments with native integers

Browse source 
The original idea was to optimize away the condition by integrating it directly
into the CMP instruction. However, with native integers this requires an extra
I2F instruction. It is also fishy because the negation used didn't really honor
ieee754 float comparison rules, not to mention the CMP instruction itself
(being pretty much a legacy instruction) doesn't really have defined special
float value behavior in any case.
So, use UCMP and adjust the code trying to optimize the condition away
accordingly (I have absolutely no idea if such conditions are actually hit
or would be translated away somewhere else already).

v2: cosmetic changes

No piglit regressions on llvmpipe.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
This commit is contained in:
Roland Scheidegger 2014-12-05 23:08:34 +01:00
parent 6f2cf5f3d0
commit d8da6decea
1 changed files with 46 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

64
src/mesa/state_tracker/st_glsl_to_tgsi.cpp
View file

@ -2288,6 +2288,37 @@ glsl_to_tgsi_visitor::process_move_condition(ir_rvalue *ir)
bool switch_order = false;
ir_expression *const expr = ir->as_expression();
if (native_integers) {
if ((expr != NULL) && (expr->get_num_operands() == 2)) {
enum glsl_base_type type = expr->operands[0]->type->base_type;
if (type == GLSL_TYPE_INT || type == GLSL_TYPE_UINT ||
type == GLSL_TYPE_BOOL) {
if (expr->operation == ir_binop_equal) {
if (expr->operands[0]->is_zero()) {
src_ir = expr->operands[1];
switch_order = true;
}
else if (expr->operands[1]->is_zero()) {
src_ir = expr->operands[0];
switch_order = true;
}
}
else if (expr->operation == ir_binop_nequal) {
if (expr->operands[0]->is_zero()) {
src_ir = expr->operands[1];
}
else if (expr->operands[1]->is_zero()) {
src_ir = expr->operands[0];
}
}
}
}
src_ir->accept(this);
return switch_order;
}
if ((expr != NULL) && (expr->get_num_operands() == 2)) {
bool zero_on_left = false;
@ -2379,7 +2410,7 @@ glsl_to_tgsi_visitor::emit_block_mov(ir_assignment *ir, const struct glsl_type *
const struct glsl_type *vec_type;
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
type->vector_elements, 1);
type->vector_elements, 1);
for (int i = 0; i < type->matrix_columns; i++) {
emit_block_mov(ir, vec_type, l, r);
@ -2447,7 +2478,7 @@ glsl_to_tgsi_visitor::visit(ir_assignment *ir)
swizzles[i] = first_enabled_chan;
}
r.swizzle = MAKE_SWIZZLE4(swizzles[0], swizzles[1],
swizzles[2], swizzles[3]);
swizzles[2], swizzles[3]);
}
assert(l.file != PROGRAM_UNDEFINED);
@ -2460,24 +2491,21 @@ glsl_to_tgsi_visitor::visit(ir_assignment *ir)
for (i = 0; i < type_size(ir->lhs->type); i++) {
st_src_reg l_src = st_src_reg(l);
st_src_reg condition_temp = condition;
st_src_reg op1, op2;
l_src.swizzle = swizzle_for_size(ir->lhs->type->vector_elements);
if (native_integers) {
/* This is necessary because TGSI's CMP instruction expects the
* condition to be a float, and we store booleans as integers.
* TODO: really want to avoid i2f path and use UCMP. Requires
* changes to process_move_condition though too.
*/
condition_temp = get_temp(glsl_type::vec4_type);
condition.negate = 0;
emit(ir, TGSI_OPCODE_I2F, st_dst_reg(condition_temp), condition);
condition_temp.swizzle = condition.swizzle;
}
op1 = r;
op2 = l_src;
if (switch_order) {
emit(ir, TGSI_OPCODE_CMP, l, condition_temp, l_src, r);
} else {
emit(ir, TGSI_OPCODE_CMP, l, condition_temp, r, l_src);
op1 = l_src;
op2 = r;
}
if (native_integers) {
emit(ir, TGSI_OPCODE_UCMP, l, condition_temp, op1, op2);
}
else {
emit(ir, TGSI_OPCODE_CMP, l, condition_temp, op1, op2);
}
l.index++;