From: Brian Paul <brianp@vmware.com>
Date: Thu, 22 Sep 2016 22:10:02 +0000 (-0600)
Subject: st/mesa: small optimization in swizzle_swizzle()
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=07d1f8faf9a7b4bdf6989de7df928105cd248251;p=mesa.git

st/mesa: small optimization in swizzle_swizzle()

Usually, there's no user-specified texture swizzle so we can optimize
the swizzle_swizzle() function and skip the loop/switch.

Reviewed-by: Charmaine Lee <charmainel@vmware.com>
---

diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
index a6135333b3e..19df6622ef1 100644
--- a/src/mesa/state_tracker/st_atom_texture.c
+++ b/src/mesa/state_tracker/st_atom_texture.c
@@ -59,6 +59,11 @@ swizzle_swizzle(unsigned swizzle1, unsigned swizzle2)
 {
    unsigned i, swz[4];
 
+   if (swizzle1 == SWIZZLE_XYZW) {
+      /* identity swizzle, no change to swizzle2 */
+      return swizzle2;
+   }
+
    for (i = 0; i < 4; i++) {
       unsigned s = GET_SWZ(swizzle1, i);
       switch (s) {