nir/search: reorder match_value to check constants first

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/36760>

src/compiler/nir/nir_algebraic.py

@@ -215,6 +215,7 @@ class Value(object):
       ${'true' if val.nnan else 'false'},
       ${'true' if val.ninf else 'false'},
       ${'true' if val.contract else 'false'},
+      ${'true' if len(val.sources) > 1 and isinstance(val.sources[1], Constant) else 'false'},
       ${val.swizzle},
       ${val.c_opcode()},
       ${val.comm_expr_idx}, ${val.comm_exprs},

src/compiler/nir/nir_search.c

@@ -426,11 +426,14 @@ match_expression(const nir_algebraic_table *table, const nir_search_expression *
 
    bool matched = true;
    for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
+      /* If src1 of the search expression is a constant, check that first since it's faster. */
+      unsigned src_idx = i < 2 ? i ^ expr->src1_is_const : i;
+
       /* 2src_commutative instructions that have 3 sources are only commutative
        * in the first two sources.  Source 2 is always source 2.
        */
-      if (!match_value(table, &state->table->values[expr->srcs[i]].value, instr,
-                       i < 2 ? i ^ comm_op_flip : i,
+      if (!match_value(table, &state->table->values[expr->srcs[src_idx]].value, instr,
+                       i < 2 ? src_idx ^ comm_op_flip : src_idx,
                        num_components, swizzle, state)) {
          matched = false;
          break;

src/compiler/nir/nir_search.h

@@ -151,6 +151,9 @@ typedef struct {
    /** Replacement contracts an expression */
    bool contract : 1;
 
+   /** Whether the second source is a nir_search_value_constant */
+   bool src1_is_const : 1;
+
    /** Whether the use of the instruction should have a swizzle. */
    int16_t swizzle : 5;