From 80361492ae7ea9fedbb5a55c72d4aea6a3d600b1 Mon Sep 17 00:00:00 2001
From: Stepan Dyatkovskiy <stpworld@narod.ru>
Date: Tue, 17 Sep 2013 09:36:11 +0000
Subject: [PATCH] Bugfix for PR17099: Wrong cast operation. MergeFunctions
 emits Bitcast instead of pointer-to-integer operation. Patch fixes
 MergeFunctions::writeThunk function. It replaces unconditional Bitcast
 creation with "Value* createCast(...)" method, that checks operand types and
 selects proper instruction. See unit-test as example.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190859 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/MergeFunctions.cpp         | 23 ++++++++++++-------
 .../Transforms/MergeFunc/merge-ptr-and-int.ll | 18 +++++++++++++++
 2 files changed, 33 insertions(+), 8 deletions(-)
 create mode 100644 test/Transforms/MergeFunc/merge-ptr-and-int.ll

diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index 4ce749cfec0..0f09b9026eb 100644
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -713,6 +713,19 @@ void MergeFunctions::writeThunkOrAlias(Function *F, Function *G) {
   writeThunk(F, G);
 }
 
+// Helper for writeThunk,
+// Selects proper bitcast operation,
+// but a bit simplier then CastInst::getCastOpcode.
+static Value* createCast(IRBuilder<false> &Builder, Value *V, Type *DestTy) {
+  Type *SrcTy = V->getType();
+  if (SrcTy->isIntegerTy() && DestTy->isPointerTy())
+    return Builder.CreateIntToPtr(V, DestTy);
+  else if (SrcTy->isPointerTy() && DestTy->isIntegerTy())
+    return Builder.CreatePtrToInt(V, DestTy);
+  else
+    return Builder.CreateBitCast(V, DestTy);
+}
+
 // Replace G with a simple tail call to bitcast(F). Also replace direct uses
 // of G with bitcast(F). Deletes G.
 void MergeFunctions::writeThunk(Function *F, Function *G) {
@@ -738,7 +751,7 @@ void MergeFunctions::writeThunk(Function *F, Function *G) {
   FunctionType *FFTy = F->getFunctionType();
   for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end();
        AI != AE; ++AI) {
-    Args.push_back(Builder.CreateBitCast(AI, FFTy->getParamType(i)));
+    Args.push_back(createCast(Builder, (Value*)AI, FFTy->getParamType(i)));
     ++i;
   }
 
@@ -748,13 +761,7 @@ void MergeFunctions::writeThunk(Function *F, Function *G) {
   if (NewG->getReturnType()->isVoidTy()) {
     Builder.CreateRetVoid();
   } else {
-    Type *RetTy = NewG->getReturnType();
-    if (CI->getType()->isIntegerTy() && RetTy->isPointerTy())
-      Builder.CreateRet(Builder.CreateIntToPtr(CI, RetTy));
-    else if (CI->getType()->isPointerTy() && RetTy->isIntegerTy())
-      Builder.CreateRet(Builder.CreatePtrToInt(CI, RetTy));
-    else
-      Builder.CreateRet(Builder.CreateBitCast(CI, RetTy));
+    Builder.CreateRet(createCast(Builder, CI, NewG->getReturnType()));
   }
 
   NewG->copyAttributesFrom(G);
diff --git a/test/Transforms/MergeFunc/merge-ptr-and-int.ll b/test/Transforms/MergeFunc/merge-ptr-and-int.ll
new file mode 100644
index 00000000000..7a178a21139
--- /dev/null
+++ b/test/Transforms/MergeFunc/merge-ptr-and-int.ll
@@ -0,0 +1,18 @@
+; RUN: opt -S -mergefunc < %s | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+; CHECK-LABEL: f0
+define void @f0(i64 %p0) {
+entry:
+  ret void
+}
+
+; CHECK-LABEL: f1
+; CHECK: ptrtoint i64*
+; CHECK: tail call void @f0(i64
+
+define void @f1(i64* %p0) {
+entry:
+  ret void
+}
+