From 8db4ddb14acde2d09938196b5d011d6591a9929b Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Tue, 19 Aug 2014 21:18:21 +0000
Subject: [PATCH] IR: Fix a missed case when threading OnlyIfReduced through
 ConstantExpr

In r216015 I missed propagating `OnlyIfReduced` through the inline
versions of `getGetElementPtr()` (I was relying on compile failures on
mismatches between the header and source signatures to get them all).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216023 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/Constants.h    |  8 ++++----
 unittests/IR/ConstantsTest.cpp | 25 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/include/llvm/IR/Constants.h b/include/llvm/IR/Constants.h
index 8591f06c72e..5625b3f5d8e 100644
--- a/include/llvm/IR/Constants.h
+++ b/include/llvm/IR/Constants.h
@@ -1036,9 +1036,9 @@ public:
   static Constant *getGetElementPtr(Constant *C, ArrayRef<Constant *> IdxList,
                                     bool InBounds = false,
                                     Type *OnlyIfReducedTy = nullptr) {
-    return getGetElementPtr(C, makeArrayRef((Value * const *)IdxList.data(),
-                                            IdxList.size()),
-                            InBounds);
+    return getGetElementPtr(
+        C, makeArrayRef((Value * const *)IdxList.data(), IdxList.size()),
+        InBounds, OnlyIfReducedTy);
   }
   static Constant *getGetElementPtr(Constant *C, Constant *Idx,
                                     bool InBounds = false,
@@ -1046,7 +1046,7 @@ public:
     // This form of the function only exists to avoid ambiguous overload
     // warnings about whether to convert Idx to ArrayRef<Constant *> or
     // ArrayRef<Value *>.
-    return getGetElementPtr(C, cast<Value>(Idx), InBounds);
+    return getGetElementPtr(C, cast<Value>(Idx), InBounds, OnlyIfReducedTy);
   }
   static Constant *getGetElementPtr(Constant *C, ArrayRef<Value *> IdxList,
                                     bool InBounds = false,
diff --git a/unittests/IR/ConstantsTest.cpp b/unittests/IR/ConstantsTest.cpp
index f14b0903548..5414b25ca3a 100644
--- a/unittests/IR/ConstantsTest.cpp
+++ b/unittests/IR/ConstantsTest.cpp
@@ -322,5 +322,30 @@ TEST(ConstantsTest, ConstantExprReplaceWithConstant) {
   ASSERT_EQ(Int2, Ref->getInitializer());
 }
 
+TEST(ConstantsTest, GEPReplaceWithConstant) {
+  LLVMContext Context;
+  std::unique_ptr<Module> M(new Module("MyModule", Context));
+
+  Type *IntTy = Type::getInt32Ty(Context);
+  Type *PtrTy = PointerType::get(IntTy, 0);
+  auto *C1 = ConstantInt::get(IntTy, 1);
+  auto *Placeholder = new GlobalVariable(
+      *M, IntTy, false, GlobalValue::ExternalWeakLinkage, nullptr);
+  auto *GEP = ConstantExpr::getGetElementPtr(Placeholder, C1);
+  ASSERT_EQ(GEP->getOperand(0), Placeholder);
+
+  auto *Ref =
+      new GlobalVariable(*M, PtrTy, false, GlobalValue::ExternalLinkage, GEP);
+  ASSERT_EQ(GEP, Ref->getInitializer());
+
+  auto *Global = new GlobalVariable(*M, PtrTy, false,
+                                    GlobalValue::ExternalLinkage, nullptr);
+  auto *Alias = GlobalAlias::create(IntTy, 0, GlobalValue::ExternalLinkage,
+                                    "alias", Global, M.get());
+  Placeholder->replaceAllUsesWith(Alias);
+  ASSERT_EQ(GEP, Ref->getInitializer());
+  ASSERT_EQ(GEP->getOperand(0), Alias);
+}
+
 }  // end anonymous namespace
 }  // end namespace llvm