Don't use register classes larger than TLI->getRegClassFor(VT).

In Thumb mode we cannot handle GPR virtual registers, even though some
instructions can. When isel is lowering a CopyFromReg, it should limit
itself to subclasses of getRegClassFor(VT).

<rdar://problem/9624323>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133210 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index e439347228..2a65d65f4f 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -76,6 +76,12 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
   // the CopyToReg'd destination register instead of creating a new vreg.
   bool MatchReg = true;
   const TargetRegisterClass *UseRC = NULL;
+  EVT VT = Node->getValueType(ResNo);
+
+  // Stick to the preferred register classes for legal types.
+  if (TLI->isTypeLegal(VT))
+    UseRC = TLI->getRegClassFor(VT);
+
   if (!IsClone && !IsCloned)
     for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
          UI != E; ++UI) {
@@ -121,10 +127,9 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
         break;
     }
 
-  EVT VT = Node->getValueType(ResNo);
   const TargetRegisterClass *SrcRC = 0, *DstRC = 0;
   SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT);
-  
+
   // Figure out the register class to create for the destreg.
   if (VRBase) {
     DstRC = MRI->getRegClass(VRBase);