From 56667002fd757cae2a3330f38a8836f4948c42fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=A4in=C3=B6=20M=C3=A4kel=C3=A4?=
 <vaino.o.makela@gmail.com>
Date: Thu, 8 Dec 2022 17:52:04 +0200
Subject: [PATCH] intel/vec4: Don't optimize multiply by 1.0 away

The SPIR-V compiler's implementation of tanh generates a multiply by 1.0
to flush denorms to zero.

Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20232>
---
 src/intel/compiler/brw_vec4.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/intel/compiler/brw_vec4.cpp b/src/intel/compiler/brw_vec4.cpp
index 6d767254221..64e6f29f52a 100644
--- a/src/intel/compiler/brw_vec4.cpp
+++ b/src/intel/compiler/brw_vec4.cpp
@@ -668,6 +668,12 @@ vec4_visitor::opt_algebraic()
 	 break;
 
       case BRW_OPCODE_MUL:
+	 if (inst->src[1].file != IMM)
+	    continue;
+
+	 if (brw_reg_type_is_floating_point(inst->src[1].type))
+	    break;
+
 	 if (inst->src[1].is_zero()) {
 	    inst->opcode = BRW_OPCODE_MOV;
 	    switch (inst->src[0].type) {