1 files changed, 48 insertions, 111 deletions

diff --git a/lib/Target/X86/X86TargetTransformInfo.cpp b/lib/Target/X86/X86TargetTransformInfo.cpp
index c04964d..91b9d40 100644
--- a/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -14,37 +14,24 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "x86tti"
 #include "X86.h"
 #include "X86TargetMachine.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Target/CostTable.h"
 #include "llvm/Target/TargetLowering.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "x86tti"
+
 // Declare the pass initialization routine locally as target-specific passes
-// don't havve a target-wide initialization entry point, and so we rely on the
+// don't have a target-wide initialization entry point, and so we rely on the
 // pass constructor initialization.
 namespace llvm {
 void initializeX86TTIPass(PassRegistry &);
 }
 
-static cl::opt<bool>
-UsePartialUnrolling("x86-use-partial-unrolling", cl::init(true),
-  cl::desc("Use partial unrolling for some X86 targets"), cl::Hidden);
-static cl::opt<unsigned>
-PartialUnrollingThreshold("x86-partial-unrolling-threshold", cl::init(0),
-  cl::desc("Threshold for X86 partial unrolling"), cl::Hidden);
-static cl::opt<unsigned>
-PartialUnrollingMaxBranches("x86-partial-max-branches", cl::init(2),
-  cl::desc("Threshold for taken branches in X86 partial unrolling"),
-  cl::Hidden);
-
 namespace {
 
 class X86TTI final : public ImmutablePass, public TargetTransformInfo {
@@ -56,7 +43,7 @@ class X86TTI final : public ImmutablePass, public TargetTransformInfo {
   unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) const;
 
 public:
-  X86TTI() : ImmutablePass(ID), ST(0), TLI(0) {
+  X86TTI() : ImmutablePass(ID), ST(nullptr), TLI(nullptr) {
     llvm_unreachable("This pass cannot be directly constructed");
   }
 
@@ -87,8 +74,6 @@ public:
   /// \name Scalar TTI Implementations
   /// @{
   PopcntSupportKind getPopcntSupport(unsigned TyWidth) const override;
-  void getUnrollingPreferences(Loop *L,
-                               UnrollingPreferences &UP) const override;
 
   /// @}
 
@@ -153,93 +138,6 @@ X86TTI::PopcntSupportKind X86TTI::getPopcntSupport(unsigned TyWidth) const {
   return ST->hasPOPCNT() ? PSK_FastHardware : PSK_Software;
 }
 
-void X86TTI::getUnrollingPreferences(Loop *L, UnrollingPreferences &UP) const {
-  if (!UsePartialUnrolling)
-    return;
-  // According to the Intel 64 and IA-32 Architectures Optimization Reference
-  // Manual, Intel Core models and later have a loop stream detector
-  // (and associated uop queue) that can benefit from partial unrolling.
-  // The relevant requirements are:
-  //  - The loop must have no more than 4 (8 for Nehalem and later) branches
-  //    taken, and none of them may be calls.
-  //  - The loop can have no more than 18 (28 for Nehalem and later) uops.
-
-  // According to the Software Optimization Guide for AMD Family 15h Processors,
-  // models 30h-4fh (Steamroller and later) have a loop predictor and loop
-  // buffer which can benefit from partial unrolling.
-  // The relevant requirements are:
-  //  - The loop must have fewer than 16 branches
-  //  - The loop must have less than 40 uops in all executed loop branches
-
-  unsigned MaxBranches, MaxOps;
-  if (PartialUnrollingThreshold.getNumOccurrences() > 0) {
-    MaxBranches = PartialUnrollingMaxBranches;
-    MaxOps = PartialUnrollingThreshold;
-  } else if (ST->isAtom()) {
-    // On the Atom, the throughput for taken branches is 2 cycles. For small
-    // simple loops, expand by a small factor to hide the backedge cost.
-    MaxBranches = 2;
-    MaxOps = 10;
-  } else if (ST->hasFSGSBase() && ST->hasXOP() /* Steamroller and later */) {
-    MaxBranches = 16;
-    MaxOps = 40;
-  } else if (ST->hasFMA4() /* Any other recent AMD */) {
-    return;
-  } else if (ST->hasAVX() || ST->hasSSE42() /* Nehalem and later */) {
-    MaxBranches = 8;
-    MaxOps = 28;
-  } else if (ST->hasSSSE3() /* Intel Core */) {
-    MaxBranches = 4;
-    MaxOps = 18;
-  } else {
-    return;
-  }
-
-  // Scan the loop: don't unroll loops with calls, and count the potential
-  // number of taken branches (this is somewhat conservative because we're
-  // counting all block transitions as potential branches while in reality some
-  // of these will become implicit via block placement).
-  unsigned MaxDepth = 0;
-  for (df_iterator<BasicBlock*> DI = df_begin(L->getHeader()),
-       DE = df_end(L->getHeader()); DI != DE;) {
-    if (!L->contains(*DI)) {
-      DI.skipChildren();
-      continue;
-    }
-
-    MaxDepth = std::max(MaxDepth, DI.getPathLength());
-    if (MaxDepth > MaxBranches)
-      return;
-
-    for (BasicBlock::iterator I = DI->begin(), IE = DI->end(); I != IE; ++I)
-      if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
-        ImmutableCallSite CS(I);
-        if (const Function *F = CS.getCalledFunction()) {
-          if (!isLoweredToCall(F))
-            continue;
-        }
-
-        return;
-      }
-
-    ++DI;
-  }
-
-  // Enable runtime and partial unrolling up to the specified size.
-  UP.Partial = UP.Runtime = true;
-  UP.PartialThreshold = UP.PartialOptSizeThreshold = MaxOps;
-
-  // Set the maximum count based on the loop depth. The maximum number of
-  // branches taken in a loop (including the backedge) is equal to the maximum
-  // loop depth (the DFS path length from the loop header to any block in the
-  // loop). When the loop is unrolled, this depth (except for the backedge
-  // itself) is multiplied by the unrolling factor. This new unrolled depth
-  // must be less than the target-specific maximum branch count (which limits
-  // the number of taken branches in the uop buffer).
-  if (MaxDepth > 1)
-    UP.MaxCount = (MaxBranches-1)/(MaxDepth-1);
-}
-
 unsigned X86TTI::getNumberOfRegisters(bool Vector) const {
   if (Vector && !ST->hasSSE1())
     return 0;
@@ -283,6 +181,21 @@ unsigned X86TTI::getArithmeticInstrCost(unsigned Opcode, Type *Ty,
   int ISD = TLI->InstructionOpcodeToISD(Opcode);
   assert(ISD && "Invalid opcode");
 
+  static const CostTblEntry<MVT::SimpleValueType>
+  AVX2UniformConstCostTable[] = {
+    { ISD::SDIV, MVT::v16i16,  6 }, // vpmulhw sequence
+    { ISD::UDIV, MVT::v16i16,  6 }, // vpmulhuw sequence
+    { ISD::SDIV, MVT::v8i32,  15 }, // vpmuldq sequence
+    { ISD::UDIV, MVT::v8i32,  15 }, // vpmuludq sequence
+  };
+
+  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
+      ST->hasAVX2()) {
+    int Idx = CostTableLookup(AVX2UniformConstCostTable, ISD, LT.second);
+    if (Idx != -1)
+      return LT.first * AVX2UniformConstCostTable[Idx].Cost;
+  }
+
   static const CostTblEntry<MVT::SimpleValueType> AVX2CostTable[] = {
     // Shifts on v4i64/v8i32 on AVX2 is legal even though we declare to
     // customize them to detect the cases where shift amount is a scalar one.
@@ -350,10 +263,19 @@ unsigned X86TTI::getArithmeticInstrCost(unsigned Opcode, Type *Ty,
     { ISD::SRA,  MVT::v16i8,  4 }, // psrlw, pand, pxor, psubb.
     { ISD::SRA,  MVT::v8i16,  1 }, // psraw.
     { ISD::SRA,  MVT::v4i32,  1 }, // psrad.
+
+    { ISD::SDIV, MVT::v8i16,  6 }, // pmulhw sequence
+    { ISD::UDIV, MVT::v8i16,  6 }, // pmulhuw sequence
+    { ISD::SDIV, MVT::v4i32, 19 }, // pmuludq sequence
+    { ISD::UDIV, MVT::v4i32, 15 }, // pmuludq sequence
   };
 
   if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
       ST->hasSSE2()) {
+    // pmuldq sequence.
+    if (ISD == ISD::SDIV && LT.second == MVT::v4i32 && ST->hasSSE41())
+      return LT.first * 15;
+
     int Idx = CostTableLookup(SSE2UniformConstCostTable, ISD, LT.second);
     if (Idx != -1)
       return LT.first * SSE2UniformConstCostTable[Idx].Cost;
@@ -893,6 +815,13 @@ unsigned X86TTI::getIntImmCost(const APInt &Imm, Type *Ty) const {
   if (BitSize == 0)
     return ~0U;
 
+  // Never hoist constants larger than 128bit, because this might lead to
+  // incorrect code generation or assertions in codegen.
+  // Fixme: Create a cost model for types larger than i128 once the codegen
+  // issues have been fixed.
+  if (BitSize > 128)
+    return TCC_Free;
+
   if (Imm == 0)
     return TCC_Free;
 
@@ -908,8 +837,10 @@ unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
   assert(Ty->isIntegerTy());
 
   unsigned BitSize = Ty->getPrimitiveSizeInBits();
+  // There is no cost model for constants with a bit size of 0. Return TCC_Free
+  // here, so that constant hoisting will ignore this constant.
   if (BitSize == 0)
-    return ~0U;
+    return TCC_Free;
 
   unsigned ImmIdx = ~0U;
   switch (Opcode) {
@@ -931,15 +862,19 @@ unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
   case Instruction::SDiv:
   case Instruction::URem:
   case Instruction::SRem:
-  case Instruction::Shl:
-  case Instruction::LShr:
-  case Instruction::AShr:
   case Instruction::And:
   case Instruction::Or:
   case Instruction::Xor:
   case Instruction::ICmp:
     ImmIdx = 1;
     break;
+  // Always return TCC_Free for the shift value of a shift instruction.
+  case Instruction::Shl:
+  case Instruction::LShr:
+  case Instruction::AShr:
+    if (Idx == 1)
+      return TCC_Free;
+    break;
   case Instruction::Trunc:
   case Instruction::ZExt:
   case Instruction::SExt:
@@ -966,8 +901,10 @@ unsigned X86TTI::getIntImmCost(Intrinsic::ID IID, unsigned Idx,
   assert(Ty->isIntegerTy());
 
   unsigned BitSize = Ty->getPrimitiveSizeInBits();
+  // There is no cost model for constants with a bit size of 0. Return TCC_Free
+  // here, so that constant hoisting will ignore this constant.
   if (BitSize == 0)
-    return ~0U;
+    return TCC_Free;
 
   switch (IID) {
   default: return TCC_Free;