Kill off the 'coerce' ABI passing form. Now 'direct' and 'extend' always

have a "coerce to" type which often matches the default lowering of Clang
type to LLVM IR type, but the coerce case can be handled by making them
not be the same.

This simplifies things and fixes issues where X86-64 abi lowering would 
return coerce after making preferred types exactly match up.  This caused
us to compile:

typedef float v4f32 __attribute__((__vector_size__(16)));
v4f32 foo(v4f32 X) {
  return X+X;
}

into this code at -O0:

define <4 x float> @foo(<4 x float> %X.coerce) nounwind {
entry:
  %retval = alloca <4 x float>, align 16          ; <<4 x float>*> [#uses=2]
  %coerce = alloca <4 x float>, align 16          ; <<4 x float>*> [#uses=2]
  %X.addr = alloca <4 x float>, align 16          ; <<4 x float>*> [#uses=3]
  store <4 x float> %X.coerce, <4 x float>* %coerce
  %X = load <4 x float>* %coerce                  ; <<4 x float>> [#uses=1]
  store <4 x float> %X, <4 x float>* %X.addr
  %tmp = load <4 x float>* %X.addr                ; <<4 x float>> [#uses=1]
  %tmp1 = load <4 x float>* %X.addr               ; <<4 x float>> [#uses=1]
  %add = fadd <4 x float> %tmp, %tmp1             ; <<4 x float>> [#uses=1]
  store <4 x float> %add, <4 x float>* %retval
  %0 = load <4 x float>* %retval                  ; <<4 x float>> [#uses=1]
  ret <4 x float> %0
}

Now we get:

define <4 x float> @foo(<4 x float> %X) nounwind {
entry:
  %X.addr = alloca <4 x float>, align 16          ; <<4 x float>*> [#uses=3]
  store <4 x float> %X, <4 x float>* %X.addr
  %tmp = load <4 x float>* %X.addr                ; <<4 x float>> [#uses=1]
  %tmp1 = load <4 x float>* %X.addr               ; <<4 x float>> [#uses=1]
  %add = fadd <4 x float> %tmp, %tmp1             ; <<4 x float>> [#uses=1]
  ret <4 x float> %add
}

This implements rdar://8248065



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109733 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 138 insertions, 151 deletions

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index f0e107973c..94cfd98d07 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -245,6 +245,18 @@ const CGFunctionInfo &CodeGenTypes::getFunctionInfo(CanQualType ResTy,
 
   // Compute ABI information.
   getABIInfo().computeInfo(*FI);
+  
+  // Loop over all of the computed argument and return value info.  If any of
+  // them are direct or extend without a specified coerce type, specify the
+  // default now.
+  ABIArgInfo &RetInfo = FI->getReturnInfo();
+  if (RetInfo.canHaveCoerceToType() && RetInfo.getCoerceToType() == 0)
+    RetInfo.setCoerceToType(ConvertTypeRecursive(FI->getReturnType()));
+  
+  for (CGFunctionInfo::arg_iterator I = FI->arg_begin(), E = FI->arg_end();
+       I != E; ++I)
+    if (I->info.canHaveCoerceToType() && I->info.getCoerceToType() == 0)
+      I->info.setCoerceToType(ConvertTypeRecursive(I->type));
 
   // If this is a top-level call and ConvertTypeRecursive hit unresolved pointer
   // types, resolve them now.  These pointers may point to this function, which
@@ -592,7 +604,7 @@ CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic,
 
   case ABIArgInfo::Extend:
   case ABIArgInfo::Direct:
-    ResultType = ConvertType(RetTy, IsRecursive);
+    ResultType = RetAI.getCoerceToType();
     break;
 
   case ABIArgInfo::Indirect: {
@@ -606,10 +618,6 @@ CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic,
   case ABIArgInfo::Ignore:
     ResultType = llvm::Type::getVoidTy(getLLVMContext());
     break;
-
-  case ABIArgInfo::Coerce:
-    ResultType = RetAI.getCoerceToType();
-    break;
   }
 
   for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
@@ -620,7 +628,15 @@ CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic,
     case ABIArgInfo::Ignore:
       break;
 
-    case ABIArgInfo::Coerce: {
+    case ABIArgInfo::Indirect: {
+      // indirect arguments are always on the stack, which is addr space #0.
+      const llvm::Type *LTy = ConvertTypeForMem(it->type, IsRecursive);
+      ArgTys.push_back(llvm::PointerType::getUnqual(LTy));
+      break;
+    }
+
+    case ABIArgInfo::Extend:
+    case ABIArgInfo::Direct:
       // If the coerce-to type is a first class aggregate, flatten it.  Either
       // way is semantically identical, but fast-isel and the optimizer
       // generally likes scalar values better than FCAs.
@@ -632,19 +648,6 @@ CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic,
         ArgTys.push_back(ArgTy);
       }
       break;
-    }
-
-    case ABIArgInfo::Indirect: {
-      // indirect arguments are always on the stack, which is addr space #0.
-      const llvm::Type *LTy = ConvertTypeForMem(it->type, IsRecursive);
-      ArgTys.push_back(llvm::PointerType::getUnqual(LTy));
-      break;
-    }
-
-    case ABIArgInfo::Extend:
-    case ABIArgInfo::Direct:
-      ArgTys.push_back(ConvertType(it->type, IsRecursive));
-      break;
 
     case ABIArgInfo::Expand:
       GetExpandedTypes(it->type, ArgTys, IsRecursive);
@@ -713,8 +716,9 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
      RetAttrs |= llvm::Attribute::SExt;
    else if (RetTy->hasUnsignedIntegerRepresentation())
      RetAttrs |= llvm::Attribute::ZExt;
-   // FALLTHROUGH
+    break;
   case ABIArgInfo::Direct:
+  case ABIArgInfo::Ignore:
     break;
 
   case ABIArgInfo::Indirect:
@@ -726,10 +730,6 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
                    llvm::Attribute::ReadNone);
     break;
 
-  case ABIArgInfo::Ignore:
-  case ABIArgInfo::Coerce:
-    break;
-
   case ABIArgInfo::Expand:
     assert(0 && "Invalid ABI kind for return argument");
   }
@@ -752,42 +752,37 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
     // 'restrict' -> 'noalias' is done in EmitFunctionProlog when we
     // have the corresponding parameter variable.  It doesn't make
     // sense to do it here because parameters are so fucked up.
-
     switch (AI.getKind()) {
-    case ABIArgInfo::Coerce:
-      if (const llvm::StructType *STy =
-          dyn_cast<llvm::StructType>(AI.getCoerceToType()))
-        Index += STy->getNumElements();
-      else
-        ++Index;
-      continue;  // Skip index increment.
-
-    case ABIArgInfo::Indirect:
-      if (AI.getIndirectByVal())
-        Attributes |= llvm::Attribute::ByVal;
-
-      Attributes |=
-        llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign());
-      // byval disables readnone and readonly.
-      FuncAttrs &= ~(llvm::Attribute::ReadOnly |
-                     llvm::Attribute::ReadNone);
-      break;
-
     case ABIArgInfo::Extend:
       if (ParamType->isSignedIntegerType())
         Attributes |= llvm::Attribute::SExt;
       else if (ParamType->isUnsignedIntegerType())
         Attributes |= llvm::Attribute::ZExt;
-     // FALLS THROUGH
+      // FALL THROUGH
     case ABIArgInfo::Direct:
       if (RegParm > 0 &&
           (ParamType->isIntegerType() || ParamType->isPointerType())) {
         RegParm -=
-          (Context.getTypeSize(ParamType) + PointerWidth - 1) / PointerWidth;
+        (Context.getTypeSize(ParamType) + PointerWidth - 1) / PointerWidth;
         if (RegParm >= 0)
           Attributes |= llvm::Attribute::InReg;
       }
       // FIXME: handle sseregparm someday...
+        
+      if (const llvm::StructType *STy =
+            dyn_cast<llvm::StructType>(AI.getCoerceToType()))
+        Index += STy->getNumElements()-1;  // 1 will be added below.
+      break;
+
+    case ABIArgInfo::Indirect:
+      if (AI.getIndirectByVal())
+        Attributes |= llvm::Attribute::ByVal;
+
+      Attributes |=
+        llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign());
+      // byval disables readnone and readonly.
+      FuncAttrs &= ~(llvm::Attribute::ReadOnly |
+                     llvm::Attribute::ReadNone);
       break;
 
     case ABIArgInfo::Ignore:
@@ -871,15 +866,12 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
 
     case ABIArgInfo::Extend:
     case ABIArgInfo::Direct: {
-      assert(AI != Fn->arg_end() && "Argument mismatch!");
-      llvm::Value *V = AI;
-      if (hasAggregateLLVMType(Ty)) {
-        // Create a temporary alloca to hold the argument; the rest of
-        // codegen expects to access aggregates & complex values by
-        // reference.
-        V = CreateMemTemp(Ty);
-        Builder.CreateStore(AI, V);
-      } else {
+      // If we have the trivial case, handle it with no muss and fuss.
+      if (!isa<llvm::StructType>(ArgI.getCoerceToType()) &&
+          ArgI.getCoerceToType() == ConvertType(Ty)) {
+        assert(AI != Fn->arg_end() && "Argument mismatch!");
+        llvm::Value *V = AI;
+        
         if (Arg->getType().isRestrictQualified())
           AI->addAttr(llvm::Attribute::NoAlias);
 
@@ -888,40 +880,10 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
           // "void a(x) short x; {..."
           V = EmitScalarConversion(V, Ty, Arg->getType());
         }
+        EmitParmDecl(*Arg, V);
+        break;
       }
-      EmitParmDecl(*Arg, V);
-      break;
-    }
 
-    case ABIArgInfo::Expand: {
-      // If this structure was expanded into multiple arguments then
-      // we need to create a temporary and reconstruct it from the
-      // arguments.
-      llvm::Value *Temp = CreateMemTemp(Ty, Arg->getName() + ".addr");
-      // FIXME: What are the right qualifiers here?
-      llvm::Function::arg_iterator End =
-        ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp, Qualifiers()), AI);
-      EmitParmDecl(*Arg, Temp);
-
-      // Name the arguments used in expansion and increment AI.
-      unsigned Index = 0;
-      for (; AI != End; ++AI, ++Index)
-        AI->setName(Arg->getName() + "." + llvm::Twine(Index));
-      continue;
-    }
-
-    case ABIArgInfo::Ignore:
-      // Initialize the local variable appropriately.
-      if (hasAggregateLLVMType(Ty)) {
-        EmitParmDecl(*Arg, CreateMemTemp(Ty));
-      } else {
-        EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())));
-      }
-
-      // Skip increment, no matching LLVM parameter.
-      continue;
-
-    case ABIArgInfo::Coerce: {
       llvm::AllocaInst *Alloca = CreateMemTemp(Ty, "coerce");
       
       // The alignment we need to use is the max of the requested alignment for
@@ -968,6 +930,33 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
       EmitParmDecl(*Arg, V);
       continue;  // Skip ++AI increment, already done.
     }
+
+    case ABIArgInfo::Expand: {
+      // If this structure was expanded into multiple arguments then
+      // we need to create a temporary and reconstruct it from the
+      // arguments.
+      llvm::Value *Temp = CreateMemTemp(Ty, Arg->getName() + ".addr");
+      // FIXME: What are the right qualifiers here?
+      llvm::Function::arg_iterator End =
+        ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp, Qualifiers()), AI);
+      EmitParmDecl(*Arg, Temp);
+
+      // Name the arguments used in expansion and increment AI.
+      unsigned Index = 0;
+      for (; AI != End; ++AI, ++Index)
+        AI->setName(Arg->getName() + "." + llvm::Twine(Index));
+      continue;
+    }
+
+    case ABIArgInfo::Ignore:
+      // Initialize the local variable appropriately.
+      if (hasAggregateLLVMType(Ty))
+        EmitParmDecl(*Arg, CreateMemTemp(Ty));
+      else
+        EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())));
+
+      // Skip increment, no matching LLVM parameter.
+      continue;
     }
 
     ++AI;
@@ -1001,38 +990,39 @@ void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI) {
     break;
 
   case ABIArgInfo::Extend:
-  case ABIArgInfo::Direct: {
-    // The internal return value temp always will have pointer-to-return-type
-    // type, just do a load.
-      
-    // If the instruction right before the insertion point is a store to the
-    // return value, we can elide the load, zap the store, and usually zap the
-    // alloca.
-    llvm::BasicBlock *InsertBB = Builder.GetInsertBlock();
-    llvm::StoreInst *SI = 0;
-    if (InsertBB->empty() || 
-        !(SI = dyn_cast<llvm::StoreInst>(&InsertBB->back())) ||
-        SI->getPointerOperand() != ReturnValue || SI->isVolatile()) {
-      RV = Builder.CreateLoad(ReturnValue);
-    } else {
-      // Get the stored value and nuke the now-dead store.
-      RetDbgLoc = SI->getDebugLoc();
-      RV = SI->getValueOperand();
-      SI->eraseFromParent();
-      
-      // If that was the only use of the return value, nuke it as well now.
-      if (ReturnValue->use_empty() && isa<llvm::AllocaInst>(ReturnValue)) {
-        cast<llvm::AllocaInst>(ReturnValue)->eraseFromParent();
-        ReturnValue = 0;
+  case ABIArgInfo::Direct:
+    
+    if (RetAI.getCoerceToType() == ConvertType(RetTy)) {
+      // The internal return value temp always will have pointer-to-return-type
+      // type, just do a load.
+        
+      // If the instruction right before the insertion point is a store to the
+      // return value, we can elide the load, zap the store, and usually zap the
+      // alloca.
+      llvm::BasicBlock *InsertBB = Builder.GetInsertBlock();
+      llvm::StoreInst *SI = 0;
+      if (InsertBB->empty() || 
+          !(SI = dyn_cast<llvm::StoreInst>(&InsertBB->back())) ||
+          SI->getPointerOperand() != ReturnValue || SI->isVolatile()) {
+        RV = Builder.CreateLoad(ReturnValue);
+      } else {
+        // Get the stored value and nuke the now-dead store.
+        RetDbgLoc = SI->getDebugLoc();
+        RV = SI->getValueOperand();
+        SI->eraseFromParent();
+        
+        // If that was the only use of the return value, nuke it as well now.
+        if (ReturnValue->use_empty() && isa<llvm::AllocaInst>(ReturnValue)) {
+          cast<llvm::AllocaInst>(ReturnValue)->eraseFromParent();
+          ReturnValue = 0;
+        }
       }
+    } else {
+      RV = CreateCoercedLoad(ReturnValue, RetAI.getCoerceToType(), *this);
     }
     break;
-  }
-  case ABIArgInfo::Ignore:
-    break;
 
-  case ABIArgInfo::Coerce:
-    RV = CreateCoercedLoad(ReturnValue, RetAI.getCoerceToType(), *this);
+  case ABIArgInfo::Ignore:
     break;
 
   case ABIArgInfo::Expand:
@@ -1145,24 +1135,20 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       }
       break;
 
-    case ABIArgInfo::Extend:
-    case ABIArgInfo::Direct:
-      if (RV.isScalar()) {
-        Args.push_back(RV.getScalarVal());
-      } else if (RV.isComplex()) {
-        llvm::Value *Tmp = llvm::UndefValue::get(ConvertType(I->second));
-        Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().first, 0);
-        Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().second, 1);
-        Args.push_back(Tmp);
-      } else {
-        Args.push_back(Builder.CreateLoad(RV.getAggregateAddr()));
-      }
-      break;
-
     case ABIArgInfo::Ignore:
       break;
+        
+    case ABIArgInfo::Extend:
+    case ABIArgInfo::Direct: {
+      if (!isa<llvm::StructType>(ArgInfo.getCoerceToType()) &&
+          ArgInfo.getCoerceToType() == ConvertType(info_it->type)) {
+        if (RV.isScalar())
+          Args.push_back(RV.getScalarVal());
+        else
+          Args.push_back(Builder.CreateLoad(RV.getAggregateAddr()));
+        break;
+      }
 
-    case ABIArgInfo::Coerce: {
       // FIXME: Avoid the conversion through memory if possible.
       llvm::Value *SrcPtr;
       if (RV.isScalar()) {
@@ -1286,32 +1272,33 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
       return RValue::getAggregate(Args[0]);
     return RValue::get(EmitLoadOfScalar(Args[0], false, RetTy));
 
-  case ABIArgInfo::Extend:
-  case ABIArgInfo::Direct:
-    if (RetTy->isAnyComplexType()) {
-      llvm::Value *Real = Builder.CreateExtractValue(CI, 0);
-      llvm::Value *Imag = Builder.CreateExtractValue(CI, 1);
-      return RValue::getComplex(std::make_pair(Real, Imag));
-    }
-    if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
-      llvm::Value *DestPtr = ReturnValue.getValue();
-      bool DestIsVolatile = ReturnValue.isVolatile();
-
-      if (!DestPtr) {
-        DestPtr = CreateMemTemp(RetTy, "agg.tmp");
-        DestIsVolatile = false;
-      }
-      Builder.CreateStore(CI, DestPtr, DestIsVolatile);
-      return RValue::getAggregate(DestPtr);
-    }
-    return RValue::get(CI);
-
   case ABIArgInfo::Ignore:
     // If we are ignoring an argument that had a result, make sure to
     // construct the appropriate return value for our caller.
     return GetUndefRValue(RetTy);
+    
+  case ABIArgInfo::Extend:
+  case ABIArgInfo::Direct: {
+    if (RetAI.getCoerceToType() == ConvertType(RetTy)) {
+      if (RetTy->isAnyComplexType()) {
+        llvm::Value *Real = Builder.CreateExtractValue(CI, 0);
+        llvm::Value *Imag = Builder.CreateExtractValue(CI, 1);
+        return RValue::getComplex(std::make_pair(Real, Imag));
+      }
+      if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
+        llvm::Value *DestPtr = ReturnValue.getValue();
+        bool DestIsVolatile = ReturnValue.isVolatile();
 
-  case ABIArgInfo::Coerce: {
+        if (!DestPtr) {
+          DestPtr = CreateMemTemp(RetTy, "agg.tmp");
+          DestIsVolatile = false;
+        }
+        Builder.CreateStore(CI, DestPtr, DestIsVolatile);
+        return RValue::getAggregate(DestPtr);
+      }
+      return RValue::get(CI);
+    }
+      
     llvm::Value *DestPtr = ReturnValue.getValue();
     bool DestIsVolatile = ReturnValue.isVolatile();