From d76fb3b2b1ac840e814bd2c49e24112c99eaf168 Mon Sep 17 00:00:00 2001
From: Emma Anholt <emma@anholt.net>
Date: Wed, 22 Feb 2023 13:16:40 -0800
Subject: [PATCH] glsl/opt_algebraic: Drop the flrp recognizer.
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No change to r300.

freedreno looks mixed but slightly positive in instructions:

total instructions in shared programs: 11012472 -> 11012453 (<.01%)
instructions in affected programs: 8250 -> 8231 (-0.23%)
helped: 16
HURT: 50

Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21475>
---
 src/compiler/glsl/opt_algebraic.cpp | 53 -----------------------------
 1 file changed, 53 deletions(-)

diff --git a/src/compiler/glsl/opt_algebraic.cpp b/src/compiler/glsl/opt_algebraic.cpp
index e2e2c8798ee..732055943da 100644
--- a/src/compiler/glsl/opt_algebraic.cpp
+++ b/src/compiler/glsl/opt_algebraic.cpp
@@ -284,59 +284,6 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       if (op_const[1] && !op_const[0])
 	 reassociate_constant(ir, 1, op_const[1], op_expr[0]);
 
-      /* Replace (-x + y) * a + x and commutative variations with lrp(x, y, a).
-       *
-       * (-x + y) * a + x
-       * (x * -a) + (y * a) + x
-       * x + (x * -a) + (y * a)
-       * x * (1 - a) + y * a
-       * lrp(x, y, a)
-       */
-      for (int mul_pos = 0; mul_pos < 2; mul_pos++) {
-         ir_expression *mul = op_expr[mul_pos];
-
-         if (!mul || mul->operation != ir_binop_mul)
-            continue;
-
-         /* Multiply found on one of the operands. Now check for an
-          * inner addition operation.
-          */
-         for (int inner_add_pos = 0; inner_add_pos < 2; inner_add_pos++) {
-            ir_expression *inner_add =
-               mul->operands[inner_add_pos]->as_expression();
-
-            if (!inner_add || inner_add->operation != ir_binop_add)
-               continue;
-
-            /* Inner addition found on one of the operands. Now check for
-             * one of the operands of the inner addition to be the negative
-             * of x_operand.
-             */
-            for (int neg_pos = 0; neg_pos < 2; neg_pos++) {
-               ir_expression *neg =
-                  inner_add->operands[neg_pos]->as_expression();
-
-               if (!neg || neg->operation != ir_unop_neg)
-                  continue;
-
-               ir_rvalue *x_operand = ir->operands[1 - mul_pos];
-
-               if (!neg->operands[0]->equals(x_operand))
-                  continue;
-
-               ir_rvalue *y_operand = inner_add->operands[1 - neg_pos];
-               ir_rvalue *a_operand = mul->operands[1 - inner_add_pos];
-
-               if (!x_operand->type->is_float_16_32_64() ||
-                   x_operand->type != y_operand->type ||
-                   x_operand->type != a_operand->type)
-                  continue;
-
-               return lrp(x_operand, y_operand, a_operand);
-            }
-         }
-      }
-
       break;
 
    case ir_binop_mul: