Imported Upstream version 5.18.0.179

Former-commit-id: 67aa10e65b237e1c4537630979ee99ebe1374215

external/llvm/lib/Analysis/CostModel.cpp

@@ -0,0 +1,112 @@
+//===- CostModel.cpp ------ Cost Model Analysis ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the cost model analysis. It provides a very basic cost
+// estimation for LLVM-IR. This analysis uses the services of the codegen
+// to approximate the cost of any IR instruction when lowered to machine
+// instructions. The cost results are unit-less and the cost number represents
+// the throughput of the machine assuming that all loads hit the cache, all
+// branches are predicted, etc. The cost numbers can be added in order to
+// compare two or more transformation alternatives.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+static cl::opt<TargetTransformInfo::TargetCostKind> CostKind(
+    "cost-kind", cl::desc("Target cost kind"),
+    cl::init(TargetTransformInfo::TCK_RecipThroughput),
+    cl::values(clEnumValN(TargetTransformInfo::TCK_RecipThroughput,
+                          "throughput", "Reciprocal throughput"),
+               clEnumValN(TargetTransformInfo::TCK_Latency,
+                          "latency", "Instruction latency"),
+               clEnumValN(TargetTransformInfo::TCK_CodeSize,
+                          "code-size", "Code size")));
+
+#define CM_NAME "cost-model"
+#define DEBUG_TYPE CM_NAME
+
+namespace {
+  class CostModelAnalysis : public FunctionPass {
+
+  public:
+    static char ID; // Class identification, replacement for typeinfo
+    CostModelAnalysis() : FunctionPass(ID), F(nullptr), TTI(nullptr) {
+      initializeCostModelAnalysisPass(
+        *PassRegistry::getPassRegistry());
+    }
+
+    /// Returns the expected cost of the instruction.
+    /// Returns -1 if the cost is unknown.
+    /// Note, this method does not cache the cost calculation and it
+    /// can be expensive in some cases.
+    unsigned getInstructionCost(const Instruction *I) const {
+      return TTI->getInstructionCost(I, TargetTransformInfo::TCK_RecipThroughput);
+    }
+
+  private:
+    void getAnalysisUsage(AnalysisUsage &AU) const override;
+    bool runOnFunction(Function &F) override;
+    void print(raw_ostream &OS, const Module*) const override;
+
+    /// The function that we analyze.
+    Function *F;
+    /// Target information.
+    const TargetTransformInfo *TTI;
+  };
+}  // End of anonymous namespace
+
+// Register this pass.
+char CostModelAnalysis::ID = 0;
+static const char cm_name[] = "Cost Model Analysis";
+INITIALIZE_PASS_BEGIN(CostModelAnalysis, CM_NAME, cm_name, false, true)
+INITIALIZE_PASS_END  (CostModelAnalysis, CM_NAME, cm_name, false, true)
+
+FunctionPass *llvm::createCostModelAnalysisPass() {
+  return new CostModelAnalysis();
+}
+
+void
+CostModelAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesAll();
+}
+
+bool
+CostModelAnalysis::runOnFunction(Function &F) {
+ this->F = &F;
+ auto *TTIWP = getAnalysisIfAvailable<TargetTransformInfoWrapperPass>();
+ TTI = TTIWP ? &TTIWP->getTTI(F) : nullptr;
+
+ return false;
+}
+
+void CostModelAnalysis::print(raw_ostream &OS, const Module*) const {
+  if (!F)
+    return;
+
+  for (BasicBlock &B : *F) {
+    for (Instruction &Inst : B) {
+      unsigned Cost = TTI->getInstructionCost(&Inst, CostKind);
+      if (Cost != (unsigned)-1)
+        OS << "Cost Model: Found an estimated cost of " << Cost;
+      else
+        OS << "Cost Model: Unknown cost";
+
+      OS << " for instruction: " << Inst << "\n";
+    }
+  }
+}