SelectionDAG: Fix a crash on inline asm when output register supports multiple types

Summary:
The code in SelectionDAG did not handle the case where the
register type and output types were different, but had the same size.

Reviewers: arsenm, echristo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D17940

llvm-svn: 263022

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index d63cbe681cc..798627df319 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -195,6 +195,8 @@ static SDValue getCopyFromParts(SelectionDAG &DAG, SDLoc DL,
   }
 
   // There is now one part, held in Val.  Correct it to match ValueVT.
+  // PartEVT is the type of the register class that holds the value.
+  // ValueVT is the type of the inline asm operation.
   EVT PartEVT = Val.getValueType();
 
   if (PartEVT == ValueVT)
@@ -208,6 +210,11 @@ static SDValue getCopyFromParts(SelectionDAG &DAG, SDLoc DL,
     Val = DAG.getNode(ISD::TRUNCATE, DL, PartEVT, Val);
   }
 
+  // Handle types that have the same size.
+  if (PartEVT.getSizeInBits() == ValueVT.getSizeInBits())
+    return DAG.getNode(ISD::BITCAST, DL, ValueVT, Val);
+
+  // Handle types with different sizes.
   if (PartEVT.isInteger() && ValueVT.isInteger()) {
     if (ValueVT.bitsLT(PartEVT)) {
       // For a truncate, see if we have any information to
@@ -231,9 +238,6 @@ static SDValue getCopyFromParts(SelectionDAG &DAG, SDLoc DL,
     return DAG.getNode(ISD::FP_EXTEND, DL, ValueVT, Val);
   }
 
-  if (PartEVT.getSizeInBits() == ValueVT.getSizeInBits())
-    return DAG.getNode(ISD::BITCAST, DL, ValueVT, Val);
-
   llvm_unreachable("Unknown mismatch!");
 }