commit 023e6669cc1d7d321e0bd5b5293422cd73b3d658
author Eric Anholt <eric@anholt.net> Wed Jul 22 21:35:07 2020 -0700
committer Marge Bot <eric+marge@anholt.net> Mon Aug 03 21:26:45 2020 +0000
tree b366d075fc380e3bef0da5c9335a0c2d3f90392f
parent 1c9906d5ff22234b4e2c5c1c81a42a8766706b34

i965: Enable vector shrinking in the vec4 backend.

This manages to make some extra vec operations that would turn into movs
go away.

brw shader-db:
total instructions in shared programs: 3895037 -> 3893221 (-0.05%)
total cycles in shared programs: 113832759 -> 113792154 (-0.04%)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6050>

src/intel/compiler/brw_nir.c

diff --git a/src/intel/compiler/brw_nir.c b/src/intel/compiler/brw_nir.c
index 9a6914f..510ab0b 100644
--- a/src/intel/compiler/brw_nir.c
+++ b/src/intel/compiler/brw_nir.c
@@ -516,6 +516,8 @@
 
       if (is_scalar) {
          OPT(nir_lower_alu_to_scalar, NULL, NULL);
+      } else {
+         OPT(nir_opt_shrink_vectors);
       }
 
       OPT(nir_copy_prop);