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Differential D9819 Diff 29527 include/llvm/Analysis/TargetTransformInfoImpl.h

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include/llvm/Analysis/TargetTransformInfoImpl.h

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#ifndef LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H #ifndef LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H
#define LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H #define LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H
#include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/CallSite.h" #include "llvm/IR/CallSite.h"
#include "llvm/IR/DataLayout.h" #include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h" #include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/Operator.h" #include "llvm/IR/Operator.h"
#include "llvm/IR/Type.h" #include "llvm/IR/Type.h"
namespace llvm { namespace llvm {
/// \brief Base class for use as a mix-in that aids implementing /// \brief Base class for use as a mix-in that aids implementing
/// a TargetTransformInfo-compatible class. /// a TargetTransformInfo-compatible class.
class TargetTransformInfoImplBase { class TargetTransformInfoImplBase {
▲ Show 20 Lines • Show All 57 Lines • ▼ Show 20 Lines case Instruction::Trunc:
// shift-right of the same width). // shift-right of the same width).
if (DL.isLegalInteger(DL.getTypeSizeInBits(Ty))) if (DL.isLegalInteger(DL.getTypeSizeInBits(Ty)))
return TTI::TCC_Free; return TTI::TCC_Free;
return TTI::TCC_Basic; return TTI::TCC_Basic;
} }
} }
unsigned getGEPCost(const Value *Ptr, ArrayRef<const Value *> Operands) { unsigned getGEPCost(Type *PointeeType, const Value *Ptr,
ArrayRef<const Value *> Operands) {
// In the basic model, we just assume that all-constant GEPs will be folded // In the basic model, we just assume that all-constant GEPs will be folded
// into their uses via addressing modes. // into their uses via addressing modes.
for (unsigned Idx = 0, Size = Operands.size(); Idx != Size; ++Idx) for (unsigned Idx = 0, Size = Operands.size(); Idx != Size; ++Idx)
if (!isa<Constant>(Operands[Idx])) if (!isa<Constant>(Operands[Idx]))
return TTI::TCC_Basic; return TTI::TCC_Basic;
return TTI::TCC_Free; return TTI::TCC_Free;
} }
▲ Show 20 Lines • Show All 269 Lines • ▼ Show 20 Linespublic:
unsigned getCallCost(const Function *F, ArrayRef<const Value *> Arguments) { unsigned getCallCost(const Function *F, ArrayRef<const Value *> Arguments) {
// Simply delegate to generic handling of the call. // Simply delegate to generic handling of the call.
// FIXME: We should use instsimplify or something else to catch calls which // FIXME: We should use instsimplify or something else to catch calls which
// will constant fold with these arguments. // will constant fold with these arguments.
return static_cast<T *>(this)->getCallCost(F, Arguments.size()); return static_cast<T *>(this)->getCallCost(F, Arguments.size());
} }
using BaseT::getGEPCost;
unsigned getGEPCost(Type *PointeeType, const Value *Ptr,
ArrayRef<const Value *> Operands) {
hfinkelUnsubmitted
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You should call stripPointerCasts before doing the dyn_cast.

hfinkel: You should call stripPointerCasts before doing the dyn_cast.
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Should be dyn_cast_or_null b/c the cost model should not require the base pointer be known when estimating costs.

hfinkel: Should be dyn_cast_or_null b/c the cost model should not require the base pointer be known when…
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Interesting -- when Ptr == nullptr, what is a good estimation? Fall back to using getAddressComputationCost?

jingyue: Interesting -- when Ptr == nullptr, what is a good estimation? Fall back to using…
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No, but there is another issue here. We're currently moving to give pointer an opaque type, and so you'll need to separately require a Type* on this interface. Please add that. Once you have the Type *, you should:

  1. assert that the type is equal to the pointer element type of the provided pointer (if it is provided) -- we'll remove this once we actually get rid of pointer element types, but for now we need the asserts
  2. use that type in the code below (there is a getGEPReturnType overload that takes the element type instead of the pointer itself)
  3. Make some default assumption for HasBaseReg (I think you should assume true).
hfinkel: No, but there is another issue here. We're currently moving to give pointer an opaque type, and…
const GlobalValue *BaseGV = nullptr;
if (Ptr != nullptr) {
// TODO: will remove this when a pointer can have an opaque type.
hfinkelUnsubmitted
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pointer can have -> pointers have

hfinkel: pointer can have -> pointers have
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a pointer can have -> pointers have

(when we make the change, there will be no 'can' about it, they'll have to have an opaque type).

hfinkel: a pointer can have -> pointers have (when we make the change, there will be no 'can' about it…
assert(Ptr->getType()->getScalarType()->getPointerElementType() ==
PointeeType &&
"explicit pointee type doesn't match operand's pointee type");
BaseGV = dyn_cast<GlobalValue>(Ptr->stripPointerCasts());
}
bool HasBaseReg = (BaseGV == nullptr);
int64_t BaseOffset = 0;
int64_t Scale = 0;
// Assumes the address space is 0 when Ptr is nullptr.
unsigned AS =
(Ptr == nullptr ? 0 : Ptr->getType()->getPointerAddressSpace());
auto GTI = gep_type_begin(PointerType::get(PointeeType, AS), Operands);
hfinkelUnsubmitted
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I don't understand why you're doing this. Will gep_type_begin not compile with an ArrayRef<const Value *>? If so, we should just fix that.

hfinkel: I don't understand why you're doing this. Will gep_type_begin not compile with an…
for (auto I = Operands.begin(); I != Operands.end(); ++I, ++GTI) {
if (isa<SequentialType>(*GTI)) {
int64_t ElementSize = DL.getTypeAllocSize(GTI.getIndexedType());
hfinkelUnsubmitted
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That's not right. isLegalAddressingMode takes the address space as an optional last parameter. Please propagate it.

hfinkel: That's not right. isLegalAddressingMode takes the address space as an optional last parameter.
if (const ConstantInt *ConstIdx = dyn_cast<ConstantInt>(*I)) {
BaseOffset += ConstIdx->getSExtValue() * ElementSize;
} else {
// Needs scale register.
if (Scale != 0) {
// No addressing mode takes two scale registers.
return TTI::TCC_Basic;
}
Scale = ElementSize;
}
} else {
StructType *STy = cast<StructType>(*GTI);
uint64_t Field = cast<ConstantInt>(*I)->getZExtValue();
BaseOffset += DL.getStructLayout(STy)->getElementOffset(Field);
}
}
if (static_cast<T *>(this)->isLegalAddressingMode(
PointerType::get(*GTI, AS), const_cast<GlobalValue *>(BaseGV),
haichengUnsubmitted
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I think we should use *GTI here rather than PointerType::get(*GTI, AS).

For example, on AArch64, the GEP in the following IRs can be folded

%"class.boost::array.16" = type { [24 x i32] }
%arrayidx.i17 = getelementptr inbounds %"class.boost::array.16", %"class.boost::array.16"* %moves, i64 0, i32 0, i64 %conv7                                                                               
store i32 %add, i32* %arrayidx.i17, align 4, !tbaa !18

The assembly is simple as

str     w24, [x20, x8, lsl #2]

However, isLegalAddressingMode() here returns false because we pass a wrong type.

I checked the implementation of isLegalAddressingMode() in several different backends (including ARM) and several other passes (LoopStrengthReduce and CodeGenPrepare) that call isLegalAddressingMode(). It think I am correct.

haicheng: I think we should use *GTI here rather than PointerType::get(*GTI, AS). For example, on…
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Thanks! I think you are right. Can you create a patch and add a unit test for this?

jingyue: Thanks! I think you are right. Can you create a patch and add a unit test for this?
BaseOffset, HasBaseReg, Scale, AS)) {
return TTI::TCC_Free;
}
return TTI::TCC_Basic;
}
using BaseT::getIntrinsicCost; using BaseT::getIntrinsicCost;
unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy, unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
ArrayRef<const Value *> Arguments) { ArrayRef<const Value *> Arguments) {
// Delegate to the generic intrinsic handling code. This mostly provides an // Delegate to the generic intrinsic handling code. This mostly provides an
// opportunity for targets to (for example) special case the cost of // opportunity for targets to (for example) special case the cost of
// certain intrinsics based on constants used as arguments. // certain intrinsics based on constants used as arguments.
SmallVector<Type *, 8> ParamTys; SmallVector<Type *, 8> ParamTys;
ParamTys.reserve(Arguments.size()); ParamTys.reserve(Arguments.size());
for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx) for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx)
ParamTys.push_back(Arguments[Idx]->getType()); ParamTys.push_back(Arguments[Idx]->getType());
return static_cast<T *>(this)->getIntrinsicCost(IID, RetTy, ParamTys); return static_cast<T *>(this)->getIntrinsicCost(IID, RetTy, ParamTys);
} }
unsigned getUserCost(const User *U) { unsigned getUserCost(const User *U) {
if (isa<PHINode>(U)) if (isa<PHINode>(U))
return TTI::TCC_Free; // Model all PHI nodes as free. return TTI::TCC_Free; // Model all PHI nodes as free.
if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U)) { if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U)) {
SmallVector<const Value *, 4> Indices(GEP->idx_begin(), GEP->idx_end()); SmallVector<Value *, 4> Indices(GEP->idx_begin(), GEP->idx_end());
return static_cast<T *>(this) return static_cast<T *>(this)->getGEPCost(
->getGEPCost(GEP->getPointerOperand(), Indices); GEP->getSourceElementType(), GEP->getPointerOperand(), Indices);
} }
if (auto CS = ImmutableCallSite(U)) { if (auto CS = ImmutableCallSite(U)) {
const Function *F = CS.getCalledFunction(); const Function *F = CS.getCalledFunction();
if (!F) { if (!F) {
// Just use the called value type. // Just use the called value type.
Type *FTy = CS.getCalledValue()->getType()->getPointerElementType(); Type *FTy = CS.getCalledValue()->getType()->getPointerElementType();
return static_cast<T *>(this) return static_cast<T *>(this)
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