From 84eeecf8225c7f9bc1a2e6e3c5f2ef12f805b90d Mon Sep 17 00:00:00 2001
From: Rhys Perry <pendingchaos02@gmail.com>
Date: Tue, 10 Mar 2026 16:48:56 +0000
Subject: [PATCH] nir/range_analysis: use a dense array

ministat (nir_analyze_fp_class):
Difference at 95.0% confidence
    -201983 +/- 1064.87
    -9.31575% +/- 0.0468505%
    (Student's t, pooled s = 1257.67)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40346>
---
 src/compiler/nir/nir_range_analysis.c | 23 +++++++++++++----------
 src/compiler/nir/nir_range_analysis.h |  3 +--
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/compiler/nir/nir_range_analysis.c b/src/compiler/nir/nir_range_analysis.c
index c1ea843ed2a..23af7db809e 100644
--- a/src/compiler/nir/nir_range_analysis.c
+++ b/src/compiler/nir/nir_range_analysis.c
@@ -201,7 +201,7 @@ fp_lookup(void *table, uint32_t key, uint32_t *value)
 {
    nir_fp_analysis_state *state = table;
    if (BITSET_TEST(state->bitset, key)) {
-      *value = *(uint16_t *)util_sparse_array_get(&state->arr, key);
+      *value = state->arr[key];
       return true;
    } else {
       return false;
@@ -214,7 +214,7 @@ fp_insert(void *table, uint32_t key, uint32_t value)
    nir_fp_analysis_state *state = table;
    BITSET_SET(state->bitset, key);
    state->max = MAX2(state->max, (int)key);
-   *(uint16_t *)util_sparse_array_get(&state->arr, key) = value;
+   state->arr[key] = value;
 }
 
 static fp_class_mask
@@ -1393,22 +1393,25 @@ nir_create_fp_analysis_state(nir_function_impl *impl)
 {
    nir_fp_analysis_state state;
    state.impl = impl;
-   /* Over-allocate the bitset, so that we can keep using the allocated table memory
+   /* Over-allocate, so that we can keep using the allocated table memory
     * even when new SSA values are added. */
-   state.size = BITSET_BYTES(impl->ssa_alloc + impl->ssa_alloc / 4u);
+   state.size = (impl->ssa_alloc + impl->ssa_alloc / 4u);
    state.max = -1;
-   state.bitset = calloc(state.size, 1);
-   util_sparse_array_init(&state.arr, 2, 256);
+   state.bitset = calloc(BITSET_BYTES(state.size), 1);
+   state.arr = malloc(state.size * sizeof(uint16_t));
    return state;
 }
 
 void
 nir_invalidate_fp_analysis_state(nir_fp_analysis_state *state)
 {
-   if (BITSET_BYTES(state->impl->ssa_alloc) > state->size) {
-      state->size = BITSET_BYTES(state->impl->ssa_alloc + state->impl->ssa_alloc / 4u);
+   if (state->impl->ssa_alloc > state->size) {
+      state->size = state->impl->ssa_alloc + state->impl->ssa_alloc / 4u;
+
+      free(state->arr);
       free(state->bitset);
-      state->bitset = calloc(state->size, 1);
+      state->arr = malloc(state->size * sizeof(uint16_t));
+      state->bitset = calloc(BITSET_BYTES(state->size), 1);
    } else if (state->max >= 0) {
       memset(state->bitset, 0, BITSET_BYTES(state->max + 1));
    }
@@ -1418,7 +1421,7 @@ nir_invalidate_fp_analysis_state(nir_fp_analysis_state *state)
 void
 nir_free_fp_analysis_state(nir_fp_analysis_state *state)
 {
-   util_sparse_array_finish(&state->arr);
+   free(state->arr);
    free(state->bitset);
 }
 
diff --git a/src/compiler/nir/nir_range_analysis.h b/src/compiler/nir/nir_range_analysis.h
index 534e81d705f..91ed3ef09b4 100644
--- a/src/compiler/nir/nir_range_analysis.h
+++ b/src/compiler/nir/nir_range_analysis.h
@@ -24,7 +24,6 @@
 #define _NIR_RANGE_ANALYSIS_H_
 
 #include "util/bitset.h"
-#include "util/sparse_array.h"
 #include "util/u_hash_table.h"
 #include "nir_defines.h"
 
@@ -34,7 +33,7 @@ extern "C" {
 
 typedef struct {
    nir_function_impl *impl;
-   struct util_sparse_array arr;
+   uint16_t *arr;
    BITSET_WORD *bitset;
    uint32_t size;
    int32_t max;