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gallivm: Use range analysis to generate better fmin and fmax code

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If it is known that one of the source must be a number, then the (more
efficient) GALLIVM_NAN_RETURN_OTHER_SECOND_NONNAN path can be used.

v2: s/know to be/known to be/.  Noticed by Roland.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10532>
This commit is contained in:
Ian Romanick
2021-04-28 15:41:56 -07:00
committed by Marge Bot
parent b3f3287eac
commit aaeff52bbe
2 changed files with 32 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/gallium/auxiliary/gallivm/lp_bld_nir.c
+29 -7
View File
@@ -35,6 +35,7 @@
#include "lp_bld_debug.h"
#include "lp_bld_printf.h"
#include "nir_deref.h"
#include "nir_search_helpers.h"
static void visit_cf_list(struct lp_build_nir_context *bld_base,
struct exec_list *list);
@@ -516,13 +517,15 @@ do_quantize_to_f16(struct lp_build_nir_context *bld_base,
}
static LLVMValueRef do_alu_action(struct lp_build_nir_context *bld_base,
nir_op op, unsigned src_bit_size[NIR_MAX_VEC_COMPONENTS], LLVMValueRef src[NIR_MAX_VEC_COMPONENTS])
const nir_alu_instr *instr,
unsigned src_bit_size[NIR_MAX_VEC_COMPONENTS],
LLVMValueRef src[NIR_MAX_VEC_COMPONENTS])
{
struct gallivm_state *gallivm = bld_base->base.gallivm;
LLVMBuilderRef builder = gallivm->builder;
LLVMValueRef result;
switch (op) {
switch (instr->op) {
case nir_op_b2f32:
result = emit_b2f(bld_base, src[0], 32);
break;
@@ -679,14 +682,31 @@ static LLVMValueRef do_alu_action(struct lp_build_nir_context *bld_base,
break;
case nir_op_fmax:
case nir_op_fmin: {
enum gallivm_nan_behavior minmax_nan = GALLIVM_NAN_RETURN_OTHER;
enum gallivm_nan_behavior minmax_nan;
int first = 0;
if (op == nir_op_fmin) {
/* If one of the sources is known to be a number (i.e., not NaN), then
* better code can be generated by passing that information along.
*/
if (is_a_number(bld_base->range_ht, instr, 1,
0 /* unused num_components */,
NULL /* unused swizzle */)) {
minmax_nan = GALLIVM_NAN_RETURN_OTHER_SECOND_NONNAN;
} else if (is_a_number(bld_base->range_ht, instr, 0,
0 /* unused num_components */,
NULL /* unused swizzle */)) {
first = 1;
minmax_nan = GALLIVM_NAN_RETURN_OTHER_SECOND_NONNAN;
} else {
minmax_nan = GALLIVM_NAN_RETURN_OTHER;
}
if (instr->op == nir_op_fmin) {
result = lp_build_min_ext(get_flt_bld(bld_base, src_bit_size[0]),
src[0], src[1], minmax_nan);
src[first], src[1 - first], minmax_nan);
} else {
result = lp_build_max_ext(get_flt_bld(bld_base, src_bit_size[0]),
src[0], src[1], minmax_nan);
src[first], src[1 - first], minmax_nan);
}
break;
}
@@ -1019,7 +1039,7 @@ static void visit_alu(struct lp_build_nir_context *bld_base, const nir_alu_instr
src_chan[i] = src[i];
src_chan[i] = cast_type(bld_base, src_chan[i], nir_op_infos[instr->op].input_types[i], src_bit_size[i]);
}
result[c] = do_alu_action(bld_base, instr->op, src_bit_size, src_chan);
result[c] = do_alu_action(bld_base, instr, src_bit_size, src_chan);
result[c] = cast_type(bld_base, result[c], nir_op_infos[instr->op].output_type, nir_dest_bit_size(instr->dest.dest));
}
}
@@ -2286,6 +2306,7 @@ bool lp_build_nir_llvm(
_mesa_key_pointer_equal);
bld_base->vars = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
_mesa_key_pointer_equal);
bld_base->range_ht = _mesa_pointer_hash_table_create(NULL);
func = (struct nir_function *)exec_list_get_head(&nir->functions);
@@ -2302,6 +2323,7 @@ bool lp_build_nir_llvm(
free(bld_base->ssa_defs);
ralloc_free(bld_base->vars);
ralloc_free(bld_base->regs);
ralloc_free(bld_base->range_ht);
return true;
}
src/gallium/auxiliary/gallivm/lp_bld_nir.h
+3
View File
@@ -57,6 +57,9 @@ struct lp_build_nir_context
struct hash_table *regs;
struct hash_table *vars;
/** Value range analysis hash table used in code generation. */
struct hash_table *range_ht;
nir_shader *shader;
void (*load_ubo)(struct lp_build_nir_context *bld_base,