Fix isEliminableCastPair to work correctly in the presence of pointers

with different sizes.

llvm-svn: 167018

1 files changed, 37 insertions, 0 deletions

diff --git a/llvm/unittests/VMCore/InstructionsTest.cpp b/llvm/unittests/VMCore/InstructionsTest.cpp
index 4cadc36f8f0..a3b13ce92d1 100644
--- a/llvm/unittests/VMCore/InstructionsTest.cpp
+++ b/llvm/unittests/VMCore/InstructionsTest.cpp
@@ -243,5 +243,42 @@ TEST(InstructionsTest, FPMathOperator) {
   delete I;
 }
 
+
+TEST(InstructionsTest, isEliminableCastPair) {
+  LLVMContext &C(getGlobalContext());
+
+  Type* Int32Ty = Type::getInt32Ty(C);
+  Type* Int64Ty = Type::getInt64Ty(C);
+  Type* Int64PtrTy = Type::getInt64PtrTy(C);
+
+  // Source and destination pointers have same size -> bitcast.
+  EXPECT_EQ(CastInst::isEliminableCastPair(CastInst::PtrToInt,
+                                           CastInst::IntToPtr,
+                                           Int64PtrTy, Int64Ty, Int64PtrTy,
+                                           Int32Ty, 0, Int32Ty),
+            CastInst::BitCast);
+
+  // Source and destination pointers have different sizes -> fail.
+  EXPECT_EQ(CastInst::isEliminableCastPair(CastInst::PtrToInt,
+                                           CastInst::IntToPtr,
+                                           Int64PtrTy, Int64Ty, Int64PtrTy,
+                                           Int32Ty, 0, Int64Ty),
+            0U);
+
+  // Middle pointer big enough -> bitcast.
+  EXPECT_EQ(CastInst::isEliminableCastPair(CastInst::IntToPtr,
+                                           CastInst::PtrToInt,
+                                           Int64Ty, Int64PtrTy, Int64Ty,
+                                           0, Int64Ty, 0),
+            CastInst::BitCast);
+
+  // Middle pointer too small -> fail.
+  EXPECT_EQ(CastInst::isEliminableCastPair(CastInst::IntToPtr,
+                                           CastInst::PtrToInt,
+                                           Int64Ty, Int64PtrTy, Int64Ty,
+                                           0, Int32Ty, 0),
+            0U);
+}
+
 }  // end anonymous namespace
 }  // end namespace llvm