[PATCH] D79848: [CostModel] Unify getCastInstrCost

[Sam Parker via Phabricator via llvm-commits]

samparker created this revision.
samparker added reviewers: uweigand, hfinkel, spatel, RKSimon.
Herald added subscribers: kbarton, hiraditya, nemanjai.
Herald added a project: LLVM.
samparker added parent revisions: D79164: [CostModel] getCFInstrCost, D78922: [CostModel] Remove getExtCost.
Herald added a subscriber: wuzish.

As a step towards removing getInstructionCost in D79483 <https://reviews.llvm.org/D79483>. Add the remaining cast instruction opcodes to the base implementation of getUserCost and directly return the result. This allows getInstructionThroughput to return getUserCost for the casts. This has required changes to PPC and SystemZ because they implement getUserCost and/or getCastInstrCost with adjustments for vector operations.


https://reviews.llvm.org/D79848

Files:
  llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
  llvm/lib/Analysis/TargetTransformInfo.cpp
  llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
  llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
  llvm/test/CodeGen/ARM/fragmented-args-multiple-regs.ll


Index: llvm/test/CodeGen/ARM/fragmented-args-multiple-regs.ll
===================================================================
--- llvm/test/CodeGen/ARM/fragmented-args-multiple-regs.ll
+++ llvm/test/CodeGen/ARM/fragmented-args-multiple-regs.ll
@@ -25,7 +25,6 @@
 ; CHECK: DBG_VALUE [[REG1:%[0-9]+]], $noreg, !14, !DIExpression(DW_OP_LLVM_fragment, 32, 32
 ; CHECK: DBG_VALUE [[REG2:%[0-9]+]], $noreg, !14, !DIExpression(DW_OP_LLVM_fragment, 0, 32
 ; CHECK: DBG_VALUE [[REG2]], $noreg, !15, !DIExpression({{.+}}DW_OP_LLVM_fragment, 0, 32
-; CHECK: DBG_VALUE $noreg, $noreg, !15, !DIExpression({{.+}}DW_OP_LLVM_fragment, 32, 32
 
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 
Index: llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -692,6 +692,12 @@
 int SystemZTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
                                      TTI::TargetCostKind CostKind,
                                      const Instruction *I) {
+  // FIXME: Can the logic below also be used for these cost kinds?
+  if (CostKind == TTI::TCK_CodeSize || CostKind == TTI::TCK_SizeAndLatency) {
+    int BaseCost = BaseT::getCastInstrCost(Opcode, Dst, Src, CostKind, I);
+    return BaseCost == 0 ? BaseCost : 1;
+  }
+
   unsigned DstScalarBits = Dst->getScalarSizeInBits();
   unsigned SrcScalarBits = Src->getScalarSizeInBits();
 
Index: llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
+++ llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
@@ -212,7 +212,8 @@
 unsigned
 PPCTTIImpl::getUserCost(const User *U, ArrayRef<const Value *> Operands,
                         TTI::TargetCostKind CostKind) {
-  if (U->getType()->isVectorTy()) {
+  // We already implement getCastInstrCost and perform the vector adjustment there.
+  if (!isa<CastInst>(U) && U->getType()->isVectorTy()) {
     // Instructions that need to be split should cost more.
     std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, U->getType());
     return LT.first * BaseT::getUserCost(U, Operands, CostKind);
Index: llvm/lib/Analysis/TargetTransformInfo.cpp
===================================================================
--- llvm/lib/Analysis/TargetTransformInfo.cpp
+++ llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -1258,10 +1258,8 @@
   case Instruction::Trunc:
   case Instruction::FPTrunc:
   case Instruction::BitCast:
-  case Instruction::AddrSpaceCast: {
-    Type *SrcTy = I->getOperand(0)->getType();
-    return getCastInstrCost(I->getOpcode(), I->getType(), SrcTy, CostKind, I);
-  }
+  case Instruction::AddrSpaceCast:
+    return getUserCost(I, CostKind);
   case Instruction::ExtractElement: {
     const ExtractElementInst *EEI = cast<ExtractElementInst>(I);
     ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1));
Index: llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
===================================================================
--- llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -875,15 +875,18 @@
       return TTI::TCC_Expensive;
     case Instruction::IntToPtr:
     case Instruction::PtrToInt:
+    case Instruction::SIToFP:
+    case Instruction::UIToFP:
+    case Instruction::FPToUI:
+    case Instruction::FPToSI:
     case Instruction::Trunc:
+    case Instruction::FPTrunc:
     case Instruction::BitCast:
+    case Instruction::AddrSpaceCast:
     case Instruction::FPExt:
     case Instruction::SExt:
     case Instruction::ZExt:
-      if (TargetTTI->getCastInstrCost(Opcode, Ty, OpTy, CostKind, I) ==
-          TTI::TCC_Free)
-        return TTI::TCC_Free;
-      break;
+      return TargetTTI->getCastInstrCost(Opcode, Ty, OpTy, CostKind, I);
     }
     // By default, just classify everything as 'basic'.
     return TTI::TCC_Basic;


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