Mesa (master): i965/vec4: Call opt_algebraic after opt_cse.
Matt Turner
mattst88 at kemper.freedesktop.org
Wed Oct 1 00:10:02 UTC 2014
Module: Mesa
Branch: master
Commit: 189ac077644c4ef2c6c15080b6d094410c74abdc
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=189ac077644c4ef2c6c15080b6d094410c74abdc
Author: Matt Turner <mattst88 at gmail.com>
Date: Sat Sep 27 10:34:07 2014 -0700
i965/vec4: Call opt_algebraic after opt_cse.
The next patch adds an algebraic optimization for the pattern
sqrt a, b
rcp c, a
and turns it into
sqrt a, b
rsq c, b
but many vertex shaders do
a = sqrt(b);
var1 /= a;
var2 /= a;
which generates
sqrt a, b
rcp c, a
rcp d, a
If we apply the algebraic optimization before CSE, we'll end up with
sqrt a, b
rsq c, b
rcp d, a
Applying CSE combines the RCP instructions, preventing this from
happening.
No shader-db changes.
Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
---
src/mesa/drivers/dri/i965/brw_vec4.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 022ed37..e0a3d5f 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -1790,8 +1790,8 @@ vec4_visitor::run()
OPT(dead_code_eliminate);
OPT(dead_control_flow_eliminate, this);
OPT(opt_copy_propagation);
- OPT(opt_algebraic);
OPT(opt_cse);
+ OPT(opt_algebraic);
OPT(opt_register_coalesce);
} while (progress);
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