R600: Add support for GROUP_BARRIER instruction

Reviewed-by: Vincent Lejeune<vljn at ovi.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185161 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/R600/R600Packetizer.cpp b/lib/Target/R600/R600Packetizer.cpp
index 6024fd5..4c72d22 100644
--- a/lib/Target/R600/R600Packetizer.cpp
+++ b/lib/Target/R600/R600Packetizer.cpp
@@ -82,7 +82,11 @@
       int OperandIdx = TII->getOperandIdx(BI->getOpcode(), AMDGPU::OpName::write);
       if (OperandIdx > -1 && BI->getOperand(OperandIdx).getImm() == 0)
         continue;
-      unsigned Dst = BI->getOperand(0).getReg();
+      int DstIdx = TII->getOperandIdx(BI->getOpcode(), AMDGPU::OpName::dst);
+      if (DstIdx == -1) {
+        continue;
+      }
+      unsigned Dst = BI->getOperand(DstIdx).getReg();
       if (BI->getOpcode() == AMDGPU::DOT4_r600 ||
           BI->getOpcode() == AMDGPU::DOT4_eg) {
         Result[Dst] = AMDGPU::PV_X;
@@ -154,6 +158,8 @@
       return true;
     if (TII->isTransOnly(MI))
       return true;
+    if (MI->getOpcode() == AMDGPU::GROUP_BARRIER)
+      return true;
     return false;
   }