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llvm-mirror/lib/Target/SystemZ/SystemZTargetTransformInfo.h
Chandler Carruth 98500f2974 [TTI] Make the cost APIs in TargetTransformInfo consistently use 'int'
rather than 'unsigned' for their costs.

For something like costs in particular there is a natural "negative"
value, that of savings or saved cost. As a consequence, there is a lot
of code that subtracts or creates negative values based on cost, all of
which is prone to awkwardness or bugs when dealing with an unsigned
type. Similarly, we *never* want these values to wrap, as that would
cause Very Bad code generation (likely percieved as an infinite loop as
we try to emit over 2^32 instructions or some such insanity).

All around 'int' seems a much better fit for these basic metrics. I've
added asserts to ensure that at least the TTI interface never returns
negative numbers here. If we ever have a use case for negative numbers,
we can remove this, but this way a bug where someone used '-1' to
produce a 'very large' cost will be caught by the assert.

This passes all tests, and is also UBSan clean.

No functional change intended.

Differential Revision: http://reviews.llvm.org/D11741

llvm-svn: 244080
2015-08-05 18:08:10 +00:00

67 lines
2.0 KiB
C++

//===-- SystemZTargetTransformInfo.h - SystemZ-specific TTI ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZTARGETTRANSFORMINFO_H
#define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZTARGETTRANSFORMINFO_H
#include "SystemZTargetMachine.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
namespace llvm {
class SystemZTTIImpl : public BasicTTIImplBase<SystemZTTIImpl> {
typedef BasicTTIImplBase<SystemZTTIImpl> BaseT;
typedef TargetTransformInfo TTI;
friend BaseT;
const SystemZSubtarget *ST;
const SystemZTargetLowering *TLI;
const SystemZSubtarget *getST() const { return ST; }
const SystemZTargetLowering *getTLI() const { return TLI; }
public:
explicit SystemZTTIImpl(const SystemZTargetMachine *TM, Function &F)
: BaseT(TM, F.getParent()->getDataLayout()), ST(TM->getSubtargetImpl(F)),
TLI(ST->getTargetLowering()) {}
// Provide value semantics. MSVC requires that we spell all of these out.
SystemZTTIImpl(const SystemZTTIImpl &Arg)
: BaseT(static_cast<const BaseT &>(Arg)), ST(Arg.ST), TLI(Arg.TLI) {}
SystemZTTIImpl(SystemZTTIImpl &&Arg)
: BaseT(std::move(static_cast<BaseT &>(Arg))), ST(std::move(Arg.ST)),
TLI(std::move(Arg.TLI)) {}
/// \name Scalar TTI Implementations
/// @{
int getIntImmCost(const APInt &Imm, Type *Ty);
int getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm, Type *Ty);
int getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
Type *Ty);
TTI::PopcntSupportKind getPopcntSupport(unsigned TyWidth);
/// @}
/// \name Vector TTI Implementations
/// @{
unsigned getNumberOfRegisters(bool Vector);
unsigned getRegisterBitWidth(bool Vector);
/// @}
};
} // end namespace llvm
#endif