[Mesa-dev] [PATCH 1/6] i965/fs: Log a performance warning if skipping 16-wide due to pulls.

[Kenneth Graunke]

Usually, the driver creates both 8-wide and 16-wide variants of every
fragment shader.  When 16-wide compilation fails, it logs a performance
warning explaining why only an 8-wide program exists.

However, when there are pull parameters, the driver won't even bother
trying the 16-wide compile (since it would fail).  In this case, it
failed to emit a performance warning, leaving no explanation for the
missing 16-wide program.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index a81e97f..a953310 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3058,14 +3058,18 @@ brw_wm_fs_emit(struct brw_context *brw, struct brw_wm_compile *c,
 
    exec_list *simd16_instructions = NULL;
    fs_visitor v2(brw, c, prog, fp, 16);
-   bool no16 = INTEL_DEBUG & DEBUG_NO16;
-   if (brw->gen >= 5 && c->prog_data.nr_pull_params == 0 && likely(!no16)) {
-      v2.import_uniforms(&v);
-      if (!v2.run()) {
-         perf_debug("16-wide shader failed to compile, falling back to "
-                    "8-wide at a 10-20%% performance cost: %s", v2.fail_msg);
+   if (brw->gen >= 5 && likely(!(INTEL_DEBUG & DEBUG_NO16))) {
+      if (c->prog_data.nr_pull_params == 0) {
+         /* Try a 16-wide compile */
+         v2.import_uniforms(&v);
+         if (!v2.run()) {
+            perf_debug("16-wide shader failed to compile, falling back to "
+                       "8-wide at a 10-20%% performance cost: %s", v2.fail_msg);
+         } else {
+            simd16_instructions = &v2.instructions;
+         }
       } else {
-         simd16_instructions = &v2.instructions;
+         perf_debug("Skipping 16-wide due to pull parameters.\n");
       }
    }
 
-- 
1.8.3.4