From fc2f57ed768294a7ded2375eb4c6f7a9d99c7d29 Mon Sep 17 00:00:00 2001
From: Brian Paul <brianp@vmware.com>
Date: Wed, 22 Jun 2022 12:29:24 -0600
Subject: [PATCH] llvmpipe: minor optimization in lp_linear_init_interp()

Skip multiplying by 1/w when it's 1.0.

Signed-off-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17561>
---
 src/gallium/drivers/llvmpipe/lp_linear_interp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/gallium/drivers/llvmpipe/lp_linear_interp.c b/src/gallium/drivers/llvmpipe/lp_linear_interp.c
index 1d87ef265f9..6ce76ff814a 100644
--- a/src/gallium/drivers/llvmpipe/lp_linear_interp.c
+++ b/src/gallium/drivers/llvmpipe/lp_linear_interp.c
@@ -141,7 +141,7 @@ lp_linear_init_interp(struct lp_linear_interp *interp,
    memset(dsdx_fp, 0, sizeof(dsdx_fp));
    memset(dsdy_fp, 0, sizeof(dsdy_fp));
 
-   if (perspective) {
+   if (perspective && oow != 1.0f) {
       for (unsigned j = 0; j < 4; j++) {
          if (usage_mask & (1<<j)) {
             s0[j]   =   a0[j] * oow;