make the argument passing stuff in the FCA case smarter still, by
avoiding making the FCA at all when the types exactly line up. For
example, before we made:
%struct.DeclGroup = type { i64, i64 }
define i64 @_Z3foo9DeclGroup(i64, i64) nounwind {
entry:
%D = alloca %struct.DeclGroup, align 8 ; <%struct.DeclGroup*> [#uses=3]
%2 = insertvalue %struct.DeclGroup undef, i64 %0, 0 ; <%struct.DeclGroup> [#uses=1]
%3 = insertvalue %struct.DeclGroup %2, i64 %1, 1 ; <%struct.DeclGroup> [#uses=1]
store %struct.DeclGroup %3, %struct.DeclGroup* %D
%tmp = getelementptr inbounds %struct.DeclGroup* %D, i32 0, i32 0 ; <i64*> [#uses=1]
%tmp1 = load i64* %tmp ; <i64> [#uses=1]
%tmp2 = getelementptr inbounds %struct.DeclGroup* %D, i32 0, i32 1 ; <i64*> [#uses=1]
%tmp3 = load i64* %tmp2 ; <i64> [#uses=1]
%add = add nsw i64 %tmp1, %tmp3 ; <i64> [#uses=1]
ret i64 %add
}
... which has the pointless insertvalue, which fastisel hates, now we
make:
%struct.DeclGroup = type { i64, i64 }
define i64 @_Z3foo9DeclGroup(i64, i64) nounwind {
entry:
%D = alloca %struct.DeclGroup, align 8 ; <%struct.DeclGroup*> [#uses=4]
%2 = getelementptr %struct.DeclGroup* %D, i32 0, i32 0 ; <i64*> [#uses=1]
store i64 %0, i64* %2
%3 = getelementptr %struct.DeclGroup* %D, i32 0, i32 1 ; <i64*> [#uses=1]
store i64 %1, i64* %3
%tmp = getelementptr inbounds %struct.DeclGroup* %D, i32 0, i32 0 ; <i64*> [#uses=1]
%tmp1 = load i64* %tmp ; <i64> [#uses=1]
%tmp2 = getelementptr inbounds %struct.DeclGroup* %D, i32 0, i32 1 ; <i64*> [#uses=1]
%tmp3 = load i64* %tmp2 ; <i64> [#uses=1]
%add = add nsw i64 %tmp1, %tmp3 ; <i64> [#uses=1]
ret i64 %add
}
This only kicks in when x86-64 abi lowering decides it likes us.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107104 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index eb517ed..4d72d91 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -894,29 +894,41 @@
continue;
case ABIArgInfo::Coerce: {
- // If the coerce-to type is a first class aggregate, we flatten it and
- // pass the elements. Either way is semantically identical, but fast-isel
- // and the optimizer generally likes scalar values better than FCAs.
- llvm::Value *FormalArg;
- if (const llvm::StructType *STy =
- dyn_cast<llvm::StructType>(ArgI.getCoerceToType())) {
- // Reconstruct the FCA here.
- // FIXME: If we have a direct match, do nice gep/store series.
- FormalArg = llvm::UndefValue::get(STy);
- for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
- assert(AI != Fn->arg_end() && "Argument mismatch!");
- FormalArg = Builder.CreateInsertValue(FormalArg, AI++, i);
- }
- } else {
- assert(AI != Fn->arg_end() && "Argument mismatch!");
- FormalArg = AI++;
- }
-
// FIXME: This is very wasteful; EmitParmDecl is just going to drop the
// result in a new alloca anyway, so we could just store into that
// directly if we broke the abstraction down more.
llvm::Value *V = CreateMemTemp(Ty, "coerce");
- CreateCoercedStore(FormalArg, V, /*DestIsVolatile=*/false, *this);
+
+ // If the coerce-to type is a first class aggregate, we flatten it and
+ // pass the elements. Either way is semantically identical, but fast-isel
+ // and the optimizer generally likes scalar values better than FCAs.
+ if (const llvm::StructType *STy =
+ dyn_cast<llvm::StructType>(ArgI.getCoerceToType())) {
+ // If the argument and alloca types match up, we don't have to build the
+ // FCA at all, emit a series of GEPs and stores, which is better for
+ // fast isel.
+ if (STy == cast<llvm::PointerType>(V->getType())->getElementType()) {
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ assert(AI != Fn->arg_end() && "Argument mismatch!");
+ llvm::Value *EltPtr = Builder.CreateConstGEP2_32(V, 0, i);
+ Builder.CreateStore(AI++, EltPtr);
+ }
+ } else {
+ // Reconstruct the FCA here so we can do a coerced store.
+ llvm::Value *FormalArg = llvm::UndefValue::get(STy);
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ assert(AI != Fn->arg_end() && "Argument mismatch!");
+ FormalArg = Builder.CreateInsertValue(FormalArg, AI++, i);
+ }
+ CreateCoercedStore(FormalArg, V, /*DestIsVolatile=*/false, *this);
+ }
+ } else {
+ // Simple case, just do a coerced store of the argument into the alloca.
+ assert(AI != Fn->arg_end() && "Argument mismatch!");
+ CreateCoercedStore(AI++, V, /*DestIsVolatile=*/false, *this);
+ }
+
+
// Match to what EmitParmDecl is expecting for this type.
if (!CodeGenFunction::hasAggregateLLVMType(Ty)) {
V = EmitLoadOfScalar(V, false, Ty);
@@ -1116,19 +1128,32 @@
} else
SrcPtr = RV.getAggregateAddr();
- llvm::Value *SrcVal =
- CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(), *this);
-
// If the coerce-to type is a first class aggregate, we flatten it and
// pass the elements. Either way is semantically identical, but fast-isel
// and the optimizer generally likes scalar values better than FCAs.
if (const llvm::StructType *STy =
- dyn_cast<llvm::StructType>(SrcVal->getType())) {
- // Extract the elements of the value to pass in.
- for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
- Args.push_back(Builder.CreateExtractValue(SrcVal, i));
+ dyn_cast<llvm::StructType>(ArgInfo.getCoerceToType())) {
+ // If the argument and alloca types match up, we don't have to build the
+ // FCA at all, emit a series of GEPs and loads, which is better for
+ // fast isel.
+ if (STy ==cast<llvm::PointerType>(SrcPtr->getType())->getElementType()){
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ llvm::Value *EltPtr = Builder.CreateConstGEP2_32(SrcPtr, 0, i);
+ Args.push_back(Builder.CreateLoad(EltPtr));
+ }
+ } else {
+ // Otherwise, do a coerced load the entire FCA and handle the pieces.
+ llvm::Value *SrcVal =
+ CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(), *this);
+
+ // Extract the elements of the value to pass in.
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
+ Args.push_back(Builder.CreateExtractValue(SrcVal, i));
+ }
} else {
- Args.push_back(SrcVal);
+ // In the simple case, just pass the coerced loaded value.
+ Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(),
+ *this));
}
break;