[AMDGPU] gfx908 mfma support

Differential Revision: https://reviews.llvm.org/D64584

llvm-svn: 365824
diff --git a/llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp b/llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
index c3d076e..f0d47ea 100644
--- a/llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNRegBankReassign.cpp
@@ -365,6 +365,9 @@
       continue;
 
     unsigned R = Op.getReg();
+    if (TRI->hasAGPRs(TRI->getRegClassForReg(*MRI, R)))
+      continue;
+
     unsigned ShiftedBank = Bank;
 
     if (Bank != -1 && R == Reg && Op.getSubReg()) {