[opaque pointer types] [NFC] GEP: replace get(Pointer)ElementType uses with get{Source,Result}ElementType.

Summary:
GEPOperator: provide getResultElementType alongside getSourceElementType.
This is made possible by adding a result element type field to GetElementPtrConstantExpr, which GetElementPtrInst already has.

GEP: replace get(Pointer)ElementType uses with get{Source,Result}ElementType.

Reviewers: mjacob, dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D16275

llvm-svn: 258145

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index efbd98ec4e3..bf4121346fa 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -513,7 +513,13 @@ bool FastISel::selectGetElementPtr(const User *I) {
       }
       Ty = StTy->getElementType(Field);
     } else {
-      Ty = cast<SequentialType>(Ty)->getElementType();
+      if (Ty->isPointerTy()) {
+        // The only pointer type is for the very first index,
+        // therefore the next type is the source element type.
+        Ty = cast<GEPOperator>(I)->getSourceElementType();
+      } else {
+        Ty = cast<SequentialType>(Ty)->getElementType();
+      }
 
       // If this is a constant subscript, handle it quickly.
       if (const auto *CI = dyn_cast<ConstantInt>(Idx)) {