i965: Don't treat IF or WHILE with cmod as writing the flag.

Sandybridge's IF and WHILE instructions can do an embedded comparison
with conditional mod.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 028eff23efaaa436258b1e4a91ade37f5c0c21ab..37015ec607b39b09a246f524e761b9dac939c512 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -933,7 +933,9 @@ fs_inst::reads_flag() const
 bool
 fs_inst::writes_flag() const
 {
-   return (conditional_mod && opcode != BRW_OPCODE_SEL) ||
+   return (conditional_mod && (opcode != BRW_OPCODE_SEL &&
+                               opcode != BRW_OPCODE_IF &&
+                               opcode != BRW_OPCODE_WHILE)) ||
           opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS;
 }
 

diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index 7d814ca65bdd6b8197999521739fe0fca8f3a7a6..abdab993be9bb356f0452f8e305691b4a9e0045a 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -234,7 +234,9 @@ public:
 
    bool writes_flag()
    {
-      return conditional_mod && opcode != BRW_OPCODE_SEL;
+      return (conditional_mod && (opcode != BRW_OPCODE_SEL &&
+                                  opcode != BRW_OPCODE_IF &&
+                                  opcode != BRW_OPCODE_WHILE));
    }
 };