[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

1 files changed, 13 insertions, 16 deletions

diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.h b/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
index 84f256f7372..b5398ea947f 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.h
@@ -56,7 +56,7 @@ public:
   /// @{
 
   using BaseT::getIntImmCost;
-  unsigned getIntImmCost(const APInt &Imm, Type *Ty);
+  int getIntImmCost(const APInt &Imm, Type *Ty);
 
   /// @}
 
@@ -92,34 +92,31 @@ public:
     return 1;
   }
 
-  unsigned getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
-                          Type *SubTp);
+  int getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index, Type *SubTp);
 
-  unsigned getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src);
+  int getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src);
 
-  unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy);
+  int getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy);
 
-  unsigned getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index);
+  int getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index);
 
-  unsigned getAddressComputationCost(Type *Val, bool IsComplex);
+  int getAddressComputationCost(Type *Val, bool IsComplex);
 
-  unsigned getFPOpCost(Type *Ty);
+  int getFPOpCost(Type *Ty);
 
-  unsigned getArithmeticInstrCost(
+  int getArithmeticInstrCost(
       unsigned Opcode, Type *Ty,
       TTI::OperandValueKind Op1Info = TTI::OK_AnyValue,
       TTI::OperandValueKind Op2Info = TTI::OK_AnyValue,
       TTI::OperandValueProperties Opd1PropInfo = TTI::OP_None,
       TTI::OperandValueProperties Opd2PropInfo = TTI::OP_None);
 
-  unsigned getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
-                           unsigned AddressSpace);
+  int getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
+                      unsigned AddressSpace);
 
-  unsigned getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
-                                      unsigned Factor,
-                                      ArrayRef<unsigned> Indices,
-                                      unsigned Alignment,
-                                      unsigned AddressSpace);
+  int getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy, unsigned Factor,
+                                 ArrayRef<unsigned> Indices, unsigned Alignment,
+                                 unsigned AddressSpace);
   /// @}
 };