//
//===----------------------------------------------------------------------===//
+#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CodeMetrics.h"
+#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/CallSite.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+#define DEBUG_TYPE "code-metrics"
using namespace llvm;
-/// callIsSmall - If a call is likely to lower to a single target instruction,
-/// or is otherwise deemed small return true.
-/// TODO: Perhaps calls like memcpy, strcpy, etc?
-bool llvm::callIsSmall(ImmutableCallSite CS) {
- if (isa<IntrinsicInst>(CS.getInstruction()))
- return true;
+static void completeEphemeralValues(SmallVector<const Value *, 16> &WorkSet,
+ SmallPtrSetImpl<const Value*> &EphValues) {
+ SmallPtrSet<const Value *, 32> Visited;
+
+ // Make sure that all of the items in WorkSet are in our EphValues set.
+ EphValues.insert(WorkSet.begin(), WorkSet.end());
+
+ // Note: We don't speculate PHIs here, so we'll miss instruction chains kept
+ // alive only by ephemeral values.
+
+ while (!WorkSet.empty()) {
+ const Value *V = WorkSet.front();
+ WorkSet.erase(WorkSet.begin());
+
+ if (!Visited.insert(V).second)
+ continue;
+
+ // If all uses of this value are ephemeral, then so is this value.
+ if (!std::all_of(V->user_begin(), V->user_end(),
+ [&](const User *U) { return EphValues.count(U); }))
+ continue;
+
+ EphValues.insert(V);
+ DEBUG(dbgs() << "Ephemeral Value: " << *V << "\n");
+
+ if (const User *U = dyn_cast<User>(V))
+ for (const Value *J : U->operands()) {
+ if (isSafeToSpeculativelyExecute(J))
+ WorkSet.push_back(J);
+ }
+ }
+}
+
+// Find all ephemeral values.
+void CodeMetrics::collectEphemeralValues(
+ const Loop *L, AssumptionCache *AC,
+ SmallPtrSetImpl<const Value *> &EphValues) {
+ SmallVector<const Value *, 16> WorkSet;
- const Function *F = CS.getCalledFunction();
- if (!F) return false;
+ for (auto &AssumeVH : AC->assumptions()) {
+ if (!AssumeVH)
+ continue;
+ Instruction *I = cast<Instruction>(AssumeVH);
- if (F->hasLocalLinkage()) return false;
+ // Filter out call sites outside of the loop so we don't to a function's
+ // worth of work for each of its loops (and, in the common case, ephemeral
+ // values in the loop are likely due to @llvm.assume calls in the loop).
+ if (!L->contains(I->getParent()))
+ continue;
- if (!F->hasName()) return false;
+ WorkSet.push_back(I);
+ }
- StringRef Name = F->getName();
+ completeEphemeralValues(WorkSet, EphValues);
+}
- // These will all likely lower to a single selection DAG node.
- if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
- Name == "fabs" || Name == "fabsf" || Name == "fabsl" ||
- Name == "sin" || Name == "sinf" || Name == "sinl" ||
- Name == "cos" || Name == "cosf" || Name == "cosl" ||
- Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" )
- return true;
+void CodeMetrics::collectEphemeralValues(
+ const Function *F, AssumptionCache *AC,
+ SmallPtrSetImpl<const Value *> &EphValues) {
+ SmallVector<const Value *, 16> WorkSet;
- // These are all likely to be optimized into something smaller.
- if (Name == "pow" || Name == "powf" || Name == "powl" ||
- Name == "exp2" || Name == "exp2l" || Name == "exp2f" ||
- Name == "floor" || Name == "floorf" || Name == "ceil" ||
- Name == "round" || Name == "ffs" || Name == "ffsl" ||
- Name == "abs" || Name == "labs" || Name == "llabs")
- return true;
+ for (auto &AssumeVH : AC->assumptions()) {
+ if (!AssumeVH)
+ continue;
+ Instruction *I = cast<Instruction>(AssumeVH);
+ assert(I->getParent()->getParent() == F &&
+ "Found assumption for the wrong function!");
+ WorkSet.push_back(I);
+ }
- return false;
+ completeEphemeralValues(WorkSet, EphValues);
}
/// analyzeBasicBlock - Fill in the current structure with information gleaned
/// from the specified block.
void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
- const TargetTransformInfo &TTI) {
+ const TargetTransformInfo &TTI,
+ SmallPtrSetImpl<const Value*> &EphValues) {
++NumBlocks;
unsigned NumInstsBeforeThisBB = NumInsts;
for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
II != E; ++II) {
- if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&*II))
+ // Skip ephemeral values.
+ if (EphValues.count(&*II))
continue;
// Special handling for calls.
// for that case.
if (F == BB->getParent())
isRecursive = true;
- }
-
- if (!callIsSmall(CS)) {
- // Each argument to a call takes on average one instruction to set up.
- NumInsts += CS.arg_size();
+ if (TTI.isLoweredToCall(F))
+ ++NumCalls;
+ } else {
// We don't want inline asm to count as a call - that would prevent loop
// unrolling. The argument setup cost is still real, though.
if (!isa<InlineAsm>(CS.getCalledValue()))
if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy())
++NumVectorInsts;
+ if (II->getType()->isTokenTy() && II->isUsedOutsideOfBlock(BB))
+ notDuplicatable = true;
+
if (const CallInst *CI = dyn_cast<CallInst>(II))
- if (CI->hasFnAttr(Attribute::NoDuplicate))
+ if (CI->cannotDuplicate())
notDuplicatable = true;
if (const InvokeInst *InvI = dyn_cast<InvokeInst>(II))
- if (InvI->hasFnAttr(Attribute::NoDuplicate))
+ if (InvI->cannotDuplicate())
notDuplicatable = true;
- ++NumInsts;
+ NumInsts += TTI.getUserCost(&*II);
}
if (isa<ReturnInst>(BB->getTerminator()))
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