From: Matt Turner <mattst88@gmail.com>
Date: Wed, 30 Oct 2013 04:39:52 +0000 (-0700)
Subject: i965/fs: Extend SEL peephole to handle only matching MOVs.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4532cac06a9da527549efb685c6f37ffed24ddbf;p=mesa.git

i965/fs: Extend SEL peephole to handle only matching MOVs.

Before this patch, the following code would not be optimized even though
the first two instructions were common to the then and else blocks:

   (+f0) IF
   MOV dst0 ...
   MOV dst1 ...
   MOV dst2 ...
   ELSE
   MOV dst0 ...
   MOV dst1 ...
   MOV dst3 ...
   ENDIF

This commit extends the peephole to handle this case.

No shader-db changes.

Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
---

diff --git a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
index 52be1b772e4..f2749945813 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
@@ -147,7 +147,6 @@ fs_visitor::opt_peephole_sel()
 
       fs_inst *else_mov[MAX_MOVS] = { NULL };
       fs_inst *then_mov[MAX_MOVS] = { NULL };
-      bool malformed_mov_found = false;
 
       int movs = count_movs_from_if(then_mov, else_mov, if_inst, else_inst);
 
@@ -166,7 +165,7 @@ fs_visitor::opt_peephole_sel()
          if (!then_mov[i]->dst.equals(else_mov[i]->dst) ||
              then_mov[i]->is_partial_write() ||
              else_mov[i]->is_partial_write()) {
-            malformed_mov_found = true;
+            movs = i;
             break;
          }
 
@@ -193,7 +192,7 @@ fs_visitor::opt_peephole_sel()
          }
       }
 
-      if (malformed_mov_found)
+      if (movs == 0)
          continue;
 
       /* Emit a CMP if our IF used the embedded comparison */