Split the init.trampoline intrinsic, which currently combines GCC's

init.trampoline and adjust.trampoline intrinsics, into two intrinsics
like in GCC.  While having one combined intrinsic is tempting, it is
not natural because typically the trampoline initialization needs to
be done in one function, and the result of adjust trampoline is needed
in a different (nested) function.  To get around this llvm-gcc hacks the
nested function lowering code to insert an additional parent variable
holding the adjust.trampoline result that can be accessed from the child
function.  Dragonegg doesn't have the luxury of tweaking GCC code, so it
stored the result of adjust.trampoline in the memory GCC set aside for
the trampoline itself (this is always available in the child function),
and set up some new memory (using an alloca) to hold the trampoline.
Unfortunately this breaks Go which allocates trampoline memory on the
heap and wants to use it even after the parent has exited (!).  Rather
than doing even more hacks to get Go working, it seemed best to just use
two intrinsics like in GCC.  Patch mostly by Sanjoy Das.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139140 91177308-0d34-0410-b5e6-96231b3b80d8

12 files changed, 191 insertions, 46 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index b9d841e9d8..e672512256 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -872,7 +872,8 @@ SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) {
     if (Action == TargetLowering::Legal)
       Action = TargetLowering::Expand;
     break;
-  case ISD::TRAMPOLINE:
+  case ISD::INIT_TRAMPOLINE:
+  case ISD::ADJUST_TRAMPOLINE:
   case ISD::FRAMEADDR:
   case ISD::RETURNADDR:
     // These operations lie about being legal: when they claim to be legal,
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 1c7b93af3b..ec7bfbe495 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6054,7 +6054,8 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   case ISD::CTLZ:    return "ctlz";
 
   // Trampolines
-  case ISD::TRAMPOLINE: return "trampoline";
+  case ISD::INIT_TRAMPOLINE: return "init_trampoline";
+  case ISD::ADJUST_TRAMPOLINE: return "adjust_trampoline";
 
   case ISD::CONDCODE:
     switch (cast<CondCodeSDNode>(this)->get()) {
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 0b0b98d834..d8fa0c93db 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5016,12 +5016,15 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     Ops[4] = DAG.getSrcValue(I.getArgOperand(0));
     Ops[5] = DAG.getSrcValue(F);
 
-    Res = DAG.getNode(ISD::TRAMPOLINE, dl,
-                      DAG.getVTList(TLI.getPointerTy(), MVT::Other),
-                      Ops, 6);
+    Res = DAG.getNode(ISD::INIT_TRAMPOLINE, dl, MVT::Other, Ops, 6);
 
-    setValue(&I, Res);
-    DAG.setRoot(Res.getValue(1));
+    DAG.setRoot(Res);
+    return 0;
+  }
+  case Intrinsic::adjust_trampoline: {
+    setValue(&I, DAG.getNode(ISD::ADJUST_TRAMPOLINE, dl,
+                             TLI.getPointerTy(),
+                             getValue(I.getArgOperand(0))));
     return 0;
   }
   case Intrinsic::gcroot:
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index be94b08e75..39e6c2412f 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -211,7 +211,8 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   setOperationAction(ISD::TRAP, MVT::Other, Legal);
 
   // TRAMPOLINE is custom lowered.
-  setOperationAction(ISD::TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::INIT_TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::ADJUST_TRAMPOLINE, MVT::Other, Custom);
 
   // VASTART needs to be custom lowered to use the VarArgsFrameIndex
   setOperationAction(ISD::VASTART           , MVT::Other, Custom);
@@ -1373,8 +1374,13 @@ SDValue PPCTargetLowering::LowerVAARG(SDValue Op, SelectionDAG &DAG,
   return DAG.getLoad(VT, dl, InChain, Result, MachinePointerInfo(), false, false, 0);
 }
 
-SDValue PPCTargetLowering::LowerTRAMPOLINE(SDValue Op,
-                                           SelectionDAG &DAG) const {
+SDValue PPCTargetLowering::LowerADJUST_TRAMPOLINE(SDValue Op,
+                                                  SelectionDAG &DAG) const {
+  return Op.getOperand(0);
+}
+
+SDValue PPCTargetLowering::LowerINIT_TRAMPOLINE(SDValue Op,
+                                                SelectionDAG &DAG) const {
   SDValue Chain = Op.getOperand(0);
   SDValue Trmp = Op.getOperand(1); // trampoline
   SDValue FPtr = Op.getOperand(2); // nested function
@@ -1403,16 +1409,13 @@ SDValue PPCTargetLowering::LowerTRAMPOLINE(SDValue Op,
 
   // Lower to a call to __trampoline_setup(Trmp, TrampSize, FPtr, ctx_reg)
   std::pair<SDValue, SDValue> CallResult =
-    LowerCallTo(Chain, Op.getValueType().getTypeForEVT(*DAG.getContext()),
+    LowerCallTo(Chain, Type::getVoidTy(*DAG.getContext()),
                 false, false, false, false, 0, CallingConv::C, false,
                 /*isReturnValueUsed=*/true,
                 DAG.getExternalSymbol("__trampoline_setup", PtrVT),
                 Args, DAG, dl);
 
-  SDValue Ops[] =
-    { CallResult.first, CallResult.second };
-
-  return DAG.getMergeValues(Ops, 2, dl);
+  return CallResult.second;
 }
 
 SDValue PPCTargetLowering::LowerVASTART(SDValue Op, SelectionDAG &DAG,
@@ -4499,7 +4502,8 @@ SDValue PPCTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::GlobalTLSAddress:   llvm_unreachable("TLS not implemented for PPC");
   case ISD::JumpTable:          return LowerJumpTable(Op, DAG);
   case ISD::SETCC:              return LowerSETCC(Op, DAG);
-  case ISD::TRAMPOLINE:         return LowerTRAMPOLINE(Op, DAG);
+  case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
+  case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::VASTART:
     return LowerVASTART(Op, DAG, PPCSubTarget);
 
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index a4f8e2a839..602f70abfc 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -390,7 +390,8 @@ namespace llvm {
     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSETCC(SDValue Op, SelectionDAG &DAG) const;
-    SDValue LowerTRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG,
                          const PPCSubtarget &Subtarget) const;
     SDValue LowerVAARG(SDValue Op, SelectionDAG &DAG,
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 8005408412..fa5f720ef0 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -504,7 +504,8 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
   setOperationAction(ISD::FRAME_TO_ARGS_OFFSET, MVT::i32, Custom);
   setOperationAction(ISD::FRAME_TO_ARGS_OFFSET, MVT::i64, Custom);
 
-  setOperationAction(ISD::TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::INIT_TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::ADJUST_TRAMPOLINE, MVT::Other, Custom);
 
   setOperationAction(ISD::TRAP, MVT::Other, Legal);
 
@@ -9406,8 +9407,13 @@ SDValue X86TargetLowering::LowerEH_RETURN(SDValue Op, SelectionDAG &DAG) const {
                      Chain, DAG.getRegister(StoreAddrReg, getPointerTy()));
 }
 
-SDValue X86TargetLowering::LowerTRAMPOLINE(SDValue Op,
-                                             SelectionDAG &DAG) const {
+SDValue X86TargetLowering::LowerADJUST_TRAMPOLINE(SDValue Op,
+                                                  SelectionDAG &DAG) const {
+  return Op.getOperand(0);
+}
+
+SDValue X86TargetLowering::LowerINIT_TRAMPOLINE(SDValue Op,
+                                                SelectionDAG &DAG) const {
   SDValue Root = Op.getOperand(0);
   SDValue Trmp = Op.getOperand(1); // trampoline
   SDValue FPtr = Op.getOperand(2); // nested function
@@ -9471,9 +9477,7 @@ SDValue X86TargetLowering::LowerTRAMPOLINE(SDValue Op,
                                 MachinePointerInfo(TrmpAddr, 22),
                                 false, false, 0);
 
-    SDValue Ops[] =
-      { Trmp, DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 6) };
-    return DAG.getMergeValues(Ops, 2, dl);
+    return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 6);
   } else {
     const Function *Func =
       cast<Function>(cast<SrcValueSDNode>(Op.getOperand(5))->getValue());
@@ -9553,9 +9557,7 @@ SDValue X86TargetLowering::LowerTRAMPOLINE(SDValue Op,
                                 MachinePointerInfo(TrmpAddr, 6),
                                 false, false, 1);
 
-    SDValue Ops[] =
-      { Trmp, DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 4) };
-    return DAG.getMergeValues(Ops, 2, dl);
+    return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 4);
   }
 }
 
@@ -10356,7 +10358,8 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
                                 return LowerFRAME_TO_ARGS_OFFSET(Op, DAG);
   case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
   case ISD::EH_RETURN:          return LowerEH_RETURN(Op, DAG);
-  case ISD::TRAMPOLINE:         return LowerTRAMPOLINE(Op, DAG);
+  case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
+  case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::FLT_ROUNDS_:        return LowerFLT_ROUNDS_(Op, DAG);
   case ISD::CTLZ:               return LowerCTLZ(Op, DAG);
   case ISD::CTTZ:               return LowerCTTZ(Op, DAG);
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index db59097577..e83fea95cb 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -821,7 +821,8 @@ namespace llvm {
     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFRAME_TO_ARGS_OFFSET(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEH_RETURN(SDValue Op, SelectionDAG &DAG) const;
-    SDValue LowerTRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerCTLZ(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerCTTZ(SDValue Op, SelectionDAG &DAG) const;
diff --git a/lib/Target/XCore/XCoreISelLowering.cpp b/lib/Target/XCore/XCoreISelLowering.cpp
index d23cfe0b92..3926a7f87f 100644
--- a/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/lib/Target/XCore/XCoreISelLowering.cpp
@@ -147,7 +147,8 @@ XCoreTargetLowering::XCoreTargetLowering(XCoreTargetMachine &XTM)
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);
 
   // TRAMPOLINE is custom lowered.
-  setOperationAction(ISD::TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::INIT_TRAMPOLINE, MVT::Other, Custom);
+  setOperationAction(ISD::ADJUST_TRAMPOLINE, MVT::Other, Custom);
 
   maxStoresPerMemset = maxStoresPerMemsetOptSize = 4;
   maxStoresPerMemmove = maxStoresPerMemmoveOptSize
@@ -180,7 +181,8 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::ADD:
   case ISD::SUB:              return ExpandADDSUB(Op.getNode(), DAG);
   case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
-  case ISD::TRAMPOLINE:       return LowerTRAMPOLINE(Op, DAG);
+  case ISD::INIT_TRAMPOLINE:  return LowerINIT_TRAMPOLINE(Op, DAG);
+  case ISD::ADJUST_TRAMPOLINE: return LowerADJUST_TRAMPOLINE(Op, DAG);
   default:
     llvm_unreachable("unimplemented operand");
     return SDValue();
@@ -789,7 +791,12 @@ SDValue XCoreTargetLowering::LowerFRAMEADDR(SDValue Op,
 }
 
 SDValue XCoreTargetLowering::
-LowerTRAMPOLINE(SDValue Op, SelectionDAG &DAG) const {
+LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const {
+  return Op.getOperand(0);
+}
+
+SDValue XCoreTargetLowering::
+LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const {
   SDValue Chain = Op.getOperand(0);
   SDValue Trmp = Op.getOperand(1); // trampoline
   SDValue FPtr = Op.getOperand(2); // nested function
@@ -841,9 +848,7 @@ LowerTRAMPOLINE(SDValue Op, SelectionDAG &DAG) const {
                               MachinePointerInfo(TrmpAddr, 16), false, false,
                               0);
 
-  SDValue Ops[] =
-    { Trmp, DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 5) };
-  return DAG.getMergeValues(Ops, 2, dl);
+  return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains, 5);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/XCore/XCoreISelLowering.h b/lib/Target/XCore/XCoreISelLowering.h
index 246da9eee5..d6c5b329a0 100644
--- a/lib/Target/XCore/XCoreISelLowering.h
+++ b/lib/Target/XCore/XCoreISelLowering.h
@@ -145,7 +145,8 @@ namespace llvm {
     SDValue LowerUMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
-    SDValue LowerTRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
 
     // Inline asm support
     std::pair<unsigned, const TargetRegisterClass*>
diff --git a/lib/Transforms/InstCombine/InstCombine.h b/lib/Transforms/InstCombine/InstCombine.h
index c6bdb08998..be4454b878 100644
--- a/lib/Transforms/InstCombine/InstCombine.h
+++ b/lib/Transforms/InstCombine/InstCombine.h
@@ -11,6 +11,7 @@
 #define INSTCOMBINE_INSTCOMBINE_H
 
 #include "InstCombineWorklist.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/Operator.h"
 #include "llvm/Pass.h"
 #include "llvm/Analysis/ValueTracking.h"
@@ -214,7 +215,8 @@ private:
   Instruction *visitCallSite(CallSite CS);
   Instruction *tryOptimizeCall(CallInst *CI, const TargetData *TD);
   bool transformConstExprCastCall(CallSite CS);
-  Instruction *transformCallThroughTrampoline(CallSite CS);
+  Instruction *transformCallThroughTrampoline(CallSite CS,
+                                              IntrinsicInst *Tramp);
   Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
                                  bool DoXform = true);
   Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 4c9cbdb4e6..7da3343fb4 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -12,7 +12,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
 #include "llvm/Support/CallSite.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
@@ -821,6 +820,83 @@ Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) {
   return Simplifier.NewInstruction;
 }
 
+static IntrinsicInst *FindInitTrampolineFromAlloca(Value *TrampMem) {
+  // Strip off at most one level of pointer casts, looking for an alloca.  This
+  // is good enough in practice and simpler than handling any number of casts.
+  Value *Underlying = TrampMem->stripPointerCasts();
+  if (Underlying != TrampMem &&
+      (!Underlying->hasOneUse() || *Underlying->use_begin() != TrampMem))
+    return 0;
+  if (!isa<AllocaInst>(Underlying))
+    return 0;
+
+  IntrinsicInst *InitTrampoline = 0;
+  for (Value::use_iterator I = TrampMem->use_begin(), E = TrampMem->use_end();
+       I != E; I++) {
+    IntrinsicInst *II = dyn_cast<IntrinsicInst>(*I);
+    if (!II)
+      return 0;
+    if (II->getIntrinsicID() == Intrinsic::init_trampoline) {
+      if (InitTrampoline)
+        // More than one init_trampoline writes to this value.  Give up.
+        return 0;
+      InitTrampoline = II;
+      continue;
+    }
+    if (II->getIntrinsicID() == Intrinsic::adjust_trampoline)
+      // Allow any number of calls to adjust.trampoline.
+      continue;
+    return 0;
+  }
+
+  // No call to init.trampoline found.
+  if (!InitTrampoline)
+    return 0;
+
+  // Check that the alloca is being used in the expected way.
+  if (InitTrampoline->getOperand(0) != TrampMem)
+    return 0;
+
+  return InitTrampoline;
+}
+
+static IntrinsicInst *FindInitTrampolineFromBB(IntrinsicInst *AdjustTramp,
+                                               Value *TrampMem) {
+  // Visit all the previous instructions in the basic block, and try to find a
+  // init.trampoline which has a direct path to the adjust.trampoline.
+  for (BasicBlock::iterator I = AdjustTramp,
+       E = AdjustTramp->getParent()->begin(); I != E; ) {
+    Instruction *Inst = --I;
+    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
+      if (II->getIntrinsicID() == Intrinsic::init_trampoline &&
+          II->getOperand(0) == TrampMem)
+        return II;
+    if (Inst->mayWriteToMemory())
+      return 0;
+  }
+  return 0;
+}
+
+// Given a call to llvm.adjust.trampoline, find and return the corresponding
+// call to llvm.init.trampoline if the call to the trampoline can be optimized
+// to a direct call to a function.  Otherwise return NULL.
+//
+static IntrinsicInst *FindInitTrampoline(Value *Callee) {
+  Callee = Callee->stripPointerCasts();
+  IntrinsicInst *AdjustTramp = dyn_cast<IntrinsicInst>(Callee);
+  if (!AdjustTramp ||
+      AdjustTramp->getIntrinsicID() != Intrinsic::adjust_trampoline)
+    return 0;
+
+  Value *TrampMem = AdjustTramp->getOperand(0);
+
+  if (IntrinsicInst *IT = FindInitTrampolineFromAlloca(TrampMem))
+    return IT;
+  if (IntrinsicInst *IT = FindInitTrampolineFromBB(AdjustTramp, TrampMem))
+    return IT;
+  return 0;
+}
+
 // visitCallSite - Improvements for call and invoke instructions.
 //
 Instruction *InstCombiner::visitCallSite(CallSite CS) {
@@ -880,10 +956,8 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) {
     return EraseInstFromFunction(*CS.getInstruction());
   }
 
-  if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee))
-    if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0)))
-      if (In->getIntrinsicID() == Intrinsic::init_trampoline)
-        return transformCallThroughTrampoline(CS);
+  if (IntrinsicInst *II = FindInitTrampoline(Callee))
+    return transformCallThroughTrampoline(CS, II);
 
   PointerType *PTy = cast<PointerType>(Callee->getType());
   FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
@@ -1164,10 +1238,13 @@ bool InstCombiner::transformConstExprCastCall(CallSite CS) {
   return true;
 }
 
-// transformCallThroughTrampoline - Turn a call to a function created by the
-// init_trampoline intrinsic into a direct call to the underlying function.
+// transformCallThroughTrampoline - Turn a call to a function created by
+// init_trampoline / adjust_trampoline intrinsic pair into a direct call to the
+// underlying function.
 //
-Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) {
+Instruction *
+InstCombiner::transformCallThroughTrampoline(CallSite CS,
+                                             IntrinsicInst *Tramp) {
   Value *Callee = CS.getCalledValue();
   PointerType *PTy = cast<PointerType>(Callee->getType());
   FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
@@ -1178,8 +1255,8 @@ Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) {
   if (Attrs.hasAttrSomewhere(Attribute::Nest))
     return 0;
 
-  IntrinsicInst *Tramp =
-    cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0));
+  assert(Tramp &&
+         "transformCallThroughTrampoline called with incorrect CallSite.");
 
   Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts());
   PointerType *NestFPTy = cast<PointerType>(NestF->getType());
diff --git a/lib/VMCore/AutoUpgrade.cpp b/lib/VMCore/AutoUpgrade.cpp
index 572018105a..04221d461d 100644
--- a/lib/VMCore/AutoUpgrade.cpp
+++ b/lib/VMCore/AutoUpgrade.cpp
@@ -43,6 +43,26 @@ static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
   
   switch (Name[0]) {
   default: break;
+  case 'i':
+    //  This upgrades the old llvm.init.trampoline to the new
+    //  llvm.init.trampoline and llvm.adjust.trampoline pair.
+    if (Name == "init.trampoline") {
+      // The new llvm.init.trampoline returns nothing.
+      if (FTy->getReturnType()->isVoidTy())
+        break;
+
+      assert(FTy->getNumParams() == 3 && "old init.trampoline takes 3 args!");
+
+      // Change the name of the old intrinsic so that we can play with its type.
+      std::string NameTmp = F->getName();
+      F->setName("");
+      NewFn = cast<Function>(M->getOrInsertFunction(
+                               NameTmp,
+                               Type::getVoidTy(M->getContext()),
+                               FTy->getParamType(0), FTy->getParamType(1),
+                               FTy->getParamType(2), (Type *)0));
+      return true;
+    }
   case 'p':
     //  This upgrades the llvm.prefetch intrinsic to accept one more parameter,
     //  which is a instruction / data cache identifier. The old version only
@@ -216,6 +236,32 @@ void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
     CI->eraseFromParent();
     break;
   }
+  case Intrinsic::init_trampoline: {
+
+    //  Transform
+    //    %tramp = call i8* llvm.init.trampoline (i8* x, i8* y, i8* z)
+    //  to
+    //    call void llvm.init.trampoline (i8* %x, i8* %y, i8* %z)
+    //    %tramp = call i8* llvm.adjust.trampoline (i8* %x)
+
+    Function *AdjustTrampolineFn =
+      cast<Function>(Intrinsic::getDeclaration(F->getParent(),
+                                               Intrinsic::adjust_trampoline));
+
+    IRBuilder<> Builder(C);
+    Builder.SetInsertPoint(CI);
+
+    Builder.CreateCall3(NewFn, CI->getArgOperand(0), CI->getArgOperand(1),
+                        CI->getArgOperand(2));
+
+    CallInst *AdjustCall = Builder.CreateCall(AdjustTrampolineFn,
+                                              CI->getArgOperand(0),
+                                              CI->getName());
+    if (!CI->use_empty())
+      CI->replaceAllUsesWith(AdjustCall);
+    CI->eraseFromParent();
+    break;
+  }
   }
 }