From f2b3a569ae25dbba264cef93602b4147d2a723d6 Mon Sep 17 00:00:00 2001
From: Vincent Lejeune <vljn@ovi.com>
Date: Sun, 13 Oct 2013 17:56:10 +0000
Subject: [PATCH] R600: Use masked read sel for texture instructions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192554 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/R600/R600ISelLowering.cpp |  5 +++++
 test/CodeGen/R600/swizzle-export.ll  | 15 +++++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/lib/Target/R600/R600ISelLowering.cpp b/lib/Target/R600/R600ISelLowering.cpp
index 81a28be104a..3c2e3888e08 100644
--- a/lib/Target/R600/R600ISelLowering.cpp
+++ b/lib/Target/R600/R600ISelLowering.cpp
@@ -1379,6 +1379,11 @@ CompactSwizzlableVector(SelectionDAG &DAG, SDValue VectorEntry,
   };
 
   for (unsigned i = 0; i < 4; i++) {
+    if (NewBldVec[i].getOpcode() == ISD::UNDEF)
+      // We mask write here to teach later passes that the ith element of this
+      // vector is undef. Thus we can use it to reduce 128 bits reg usage,
+      // break false dependencies and additionnaly make assembly easier to read.
+      RemapSwizzle[i] = 7; // SEL_MASK_WRITE
     if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(NewBldVec[i])) {
       if (C->isZero()) {
         RemapSwizzle[i] = 4; // SEL_0
diff --git a/test/CodeGen/R600/swizzle-export.ll b/test/CodeGen/R600/swizzle-export.ll
index 02fe13a720e..9a58f667f0d 100644
--- a/test/CodeGen/R600/swizzle-export.ll
+++ b/test/CodeGen/R600/swizzle-export.ll
@@ -93,6 +93,7 @@ main_body:
 }
 
 ; EG-CHECK: @main2
+; EG-CHECK: T{{[0-9]+}}.XY__
 ; EG-CHECK: T{{[0-9]+}}.YXZ0
 
 define void @main2() #0 {
@@ -110,14 +111,12 @@ main_body:
   %10 = extractelement <4 x float> %9, i32 1
   %11 = insertelement <4 x float> undef, float %0, i32 0
   %12 = insertelement <4 x float> %11, float %1, i32 1
-  %13 = insertelement <4 x float> %12, float %2, i32 2
-  %14 = insertelement <4 x float> %13, float %3, i32 3
-  call void @llvm.R600.store.swizzle(<4 x float> %14, i32 60, i32 1)
-  %15 = insertelement <4 x float> undef, float %6, i32 0
-  %16 = insertelement <4 x float> %15, float %8, i32 1
-  %17 = insertelement <4 x float> %16, float %10, i32 2
-  %18 = insertelement <4 x float> %17, float 0.000000e+00, i32 3
-  call void @llvm.R600.store.swizzle(<4 x float> %18, i32 0, i32 2)
+  call void @llvm.R600.store.swizzle(<4 x float> %12, i32 60, i32 1)
+  %13 = insertelement <4 x float> undef, float %6, i32 0
+  %14 = insertelement <4 x float> %13, float %8, i32 1
+  %15 = insertelement <4 x float> %14, float %10, i32 2
+  %16 = insertelement <4 x float> %15, float 0.000000e+00, i32 3
+  call void @llvm.R600.store.swizzle(<4 x float> %16, i32 0, i32 2)
   ret void
 }
 
-- 
2.34.1