InstCombine: Teach icmp merging about the equivalence of bit tests and UGE/ULT with...

[oota-llvm.git] / lib / Transforms / IPO / MergeFunctions.cpp

diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index 4ce749cfec0a38dad368dd45ce04fe30ab33c8ac..33f0707f29ad20bc933cee1ce5fa3337395b7d0b 100644 (file)
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -210,16 +210,20 @@ private:
 // Any two pointers in the same address space are equivalent, intptr_t and
 // pointers are equivalent. Otherwise, standard type equivalence rules apply.
 bool FunctionComparator::isEquivalentType(Type *Ty1, Type *Ty2) const {
+
+  PointerType *PTy1 = dyn_cast<PointerType>(Ty1);
+  PointerType *PTy2 = dyn_cast<PointerType>(Ty2);
+
+  if (TD) {
+    if (PTy1 && PTy1->getAddressSpace() == 0) Ty1 = TD->getIntPtrType(Ty1);
+    if (PTy2 && PTy2->getAddressSpace() == 0) Ty2 = TD->getIntPtrType(Ty2);
+  }
+
   if (Ty1 == Ty2)
     return true;
-  if (Ty1->getTypeID() != Ty2->getTypeID()) {
-    if (TD) {
-      LLVMContext &Ctx = Ty1->getContext();
-      if (isa<PointerType>(Ty1) && Ty2 == TD->getIntPtrType(Ctx)) return true;
-      if (isa<PointerType>(Ty2) && Ty1 == TD->getIntPtrType(Ctx)) return true;
-    }
+
+  if (Ty1->getTypeID() != Ty2->getTypeID())
     return false;
-  }
 
   switch (Ty1->getTypeID()) {
   default:
@@ -241,8 +245,7 @@ bool FunctionComparator::isEquivalentType(Type *Ty1, Type *Ty2) const {
     return true;
 
   case Type::PointerTyID: {
-    PointerType *PTy1 = cast<PointerType>(Ty1);
-    PointerType *PTy2 = cast<PointerType>(Ty2);
+    assert(PTy1 && PTy2 && "Both types must be pointers here.");
     return PTy1->getAddressSpace() == PTy2->getAddressSpace();
   }
 
@@ -352,14 +355,19 @@ bool FunctionComparator::isEquivalentOperation(const Instruction *I1,
 // Determine whether two GEP operations perform the same underlying arithmetic.
 bool FunctionComparator::isEquivalentGEP(const GEPOperator *GEP1,
                                          const GEPOperator *GEP2) {
-  // When we have target data, we can reduce the GEP down to the value in bytes
-  // added to the address.
-  unsigned BitWidth = TD ? TD->getPointerSizeInBits() : 1;
-  APInt Offset1(BitWidth, 0), Offset2(BitWidth, 0);
-  if (TD &&
-      GEP1->accumulateConstantOffset(*TD, Offset1) &&
-      GEP2->accumulateConstantOffset(*TD, Offset2)) {
-    return Offset1 == Offset2;
+  unsigned AS = GEP1->getPointerAddressSpace();
+  if (AS != GEP2->getPointerAddressSpace())
+    return false;
+
+  if (TD) {
+    // When we have target data, we can reduce the GEP down to the value in bytes
+    // added to the address.
+    unsigned BitWidth = TD ? TD->getPointerSizeInBits(AS) : 1;
+    APInt Offset1(BitWidth, 0), Offset2(BitWidth, 0);
+    if (GEP1->accumulateConstantOffset(*TD, Offset1) &&
+        GEP2->accumulateConstantOffset(*TD, Offset2)) {
+      return Offset1 == Offset2;
+    }
   }
 
   if (GEP1->getPointerOperand()->getType() !=
@@ -713,6 +721,19 @@ void MergeFunctions::writeThunkOrAlias(Function *F, Function *G) {
   writeThunk(F, G);
 }
 
+// Helper for writeThunk,
+// Selects proper bitcast operation,
+// but a bit simpler 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 +759,7 @@ 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 +769,7 @@ 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);
@@ -829,6 +844,18 @@ bool MergeFunctions::insert(ComparableFunction &NewF) {
 
   const ComparableFunction &OldF = *Result.first;
 
+  // Don't merge tiny functions, since it can just end up making the function
+  // larger.
+  // FIXME: Should still merge them if they are unnamed_addr and produce an
+  // alias.
+  if (NewF.getFunc()->size() == 1) {
+    if (NewF.getFunc()->front().size() <= 2) {
+      DEBUG(dbgs() << NewF.getFunc()->getName()
+            << " is to small to bother merging\n");
+      return false;
+    }
+  }
+
   // Never thunk a strong function to a weak function.
   assert(!OldF.getFunc()->mayBeOverridden() ||
          NewF.getFunc()->mayBeOverridden());