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diff --git a/llvm/lib/Target/AArch64/SVEIntrinsicOpts.cpp b/llvm/lib/Target/AArch64/SVEIntrinsicOpts.cpp
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+//===----- SVEIntrinsicOpts - SVE ACLE Intrinsics Opts --------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Performs general IR level optimizations on SVE intrinsics.
+//
+// The main goal of this pass is to remove unnecessary reinterpret
+// intrinsics (llvm.aarch64.sve.convert.[to|from].svbool), e.g:
+//
+// %1 = @llvm.aarch64.sve.convert.to.svbool.nxv4i1(<vscale x 4 x i1> %a)
+// %2 = @llvm.aarch64.sve.convert.from.svbool.nxv4i1(<vscale x 16 x i1> %1)
+//
+// This pass also looks for ptest intrinsics & phi instructions where the
+// operands are being needlessly converted to and from svbool_t.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Utils/AArch64BaseInfo.h"
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/IntrinsicsAArch64.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/Debug.h"
+
+using namespace llvm;
+using namespace llvm::PatternMatch;
+
+#define DEBUG_TYPE "sve-intrinsic-opts"
+
+namespace llvm {
+void initializeSVEIntrinsicOptsPass(PassRegistry &);
+}
+
+namespace {
+struct SVEIntrinsicOpts : public ModulePass {
+ static char ID; // Pass identification, replacement for typeid
+ SVEIntrinsicOpts() : ModulePass(ID) {
+ initializeSVEIntrinsicOptsPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnModule(Module &M) override;
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+private:
+ static IntrinsicInst *isReinterpretToSVBool(Value *V);
+
+ static bool optimizeIntrinsic(Instruction *I);
+
+ bool optimizeFunctions(SmallSetVector<Function *, 4> &Functions);
+
+ static bool optimizeConvertFromSVBool(IntrinsicInst *I);
+ static bool optimizePTest(IntrinsicInst *I);
+
+ static bool processPhiNode(IntrinsicInst *I);
+};
+} // end anonymous namespace
+
+void SVEIntrinsicOpts::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<DominatorTreeWrapperPass>();
+ AU.setPreservesCFG();
+}
+
+char SVEIntrinsicOpts::ID = 0;
+static const char *name = "SVE intrinsics optimizations";
+INITIALIZE_PASS_BEGIN(SVEIntrinsicOpts, DEBUG_TYPE, name, false, false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
+INITIALIZE_PASS_END(SVEIntrinsicOpts, DEBUG_TYPE, name, false, false)
+
+namespace llvm {
+ModulePass *createSVEIntrinsicOptsPass() { return new SVEIntrinsicOpts(); }
+} // namespace llvm
+
+/// Returns V if it's a cast from <n x 16 x i1> (aka svbool_t), nullptr
+/// otherwise.
+IntrinsicInst *SVEIntrinsicOpts::isReinterpretToSVBool(Value *V) {
+ IntrinsicInst *I = dyn_cast<IntrinsicInst>(V);
+ if (!I)
+ return nullptr;
+
+ if (I->getIntrinsicID() != Intrinsic::aarch64_sve_convert_to_svbool)
+ return nullptr;
+
+ return I;
+}
+
+/// The function will remove redundant reinterprets casting in the presence
+/// of the control flow
+bool SVEIntrinsicOpts::processPhiNode(IntrinsicInst *X) {
+
+ SmallVector<Instruction *, 32> Worklist;
+ auto RequiredType = X->getType();
+
+ auto *PN = dyn_cast<PHINode>(X->getArgOperand(0));
+ assert(PN && "Expected Phi Node!");
+
+ // Don't create a new Phi unless we can remove the old one.
+ if (!PN->hasOneUse())
+ return false;
+
+ for (Value *IncValPhi : PN->incoming_values()) {
+ auto *Reinterpret = isReinterpretToSVBool(IncValPhi);
+ if (!Reinterpret ||
+ RequiredType != Reinterpret->getArgOperand(0)->getType())
+ return false;
+ }
+
+ // Create the new Phi
+ LLVMContext &Ctx = PN->getContext();
+ IRBuilder<> Builder(Ctx);
+ Builder.SetInsertPoint(PN);
+ PHINode *NPN = Builder.CreatePHI(RequiredType, PN->getNumIncomingValues());
+ Worklist.push_back(PN);
+
+ for (unsigned I = 0; I < PN->getNumIncomingValues(); I++) {
+ auto *Reinterpret = cast<Instruction>(PN->getIncomingValue(I));
+ NPN->addIncoming(Reinterpret->getOperand(0), PN->getIncomingBlock(I));
+ Worklist.push_back(Reinterpret);
+ }
+
+ // Cleanup Phi Node and reinterprets
+ X->replaceAllUsesWith(NPN);
+ X->eraseFromParent();
+
+ for (auto &I : Worklist)
+ if (I->use_empty())
+ I->eraseFromParent();
+
+ return true;
+}
+
+bool SVEIntrinsicOpts::optimizePTest(IntrinsicInst *I) {
+ IntrinsicInst *Op1 = dyn_cast<IntrinsicInst>(I->getArgOperand(0));
+ IntrinsicInst *Op2 = dyn_cast<IntrinsicInst>(I->getArgOperand(1));
+
+ if (Op1 && Op2 &&
+ Op1->getIntrinsicID() == Intrinsic::aarch64_sve_convert_to_svbool &&
+ Op2->getIntrinsicID() == Intrinsic::aarch64_sve_convert_to_svbool &&
+ Op1->getArgOperand(0)->getType() == Op2->getArgOperand(0)->getType()) {
+
+ Value *Ops[] = {Op1->getArgOperand(0), Op2->getArgOperand(0)};
+ Type *Tys[] = {Op1->getArgOperand(0)->getType()};
+ Module *M = I->getParent()->getParent()->getParent();
+
+ auto Fn = Intrinsic::getDeclaration(M, I->getIntrinsicID(), Tys);
+ auto CI = CallInst::Create(Fn, Ops, I->getName(), I);
+
+ I->replaceAllUsesWith(CI);
+ I->eraseFromParent();
+ if (Op1->use_empty())
+ Op1->eraseFromParent();
+ if (Op2->use_empty())
+ Op2->eraseFromParent();
+
+ return true;
+ }
+
+ return false;
+}
+
+bool SVEIntrinsicOpts::optimizeConvertFromSVBool(IntrinsicInst *I) {
+ assert(I->getIntrinsicID() == Intrinsic::aarch64_sve_convert_from_svbool &&
+ "Unexpected opcode");
+
+ // If the reinterpret instruction operand is a PHI Node
+ if (isa<PHINode>(I->getArgOperand(0)))
+ return processPhiNode(I);
+
+ // If we have a reinterpret intrinsic I of type A which is converting from
+ // another reinterpret Y of type B, and the source type of Y is A, then we can
+ // elide away both reinterprets if there are no other users of Y.
+ auto *Y = isReinterpretToSVBool(I->getArgOperand(0));
+ if (!Y)
+ return false;
+
+ Value *SourceVal = Y->getArgOperand(0);
+ if (I->getType() != SourceVal->getType())
+ return false;
+
+ I->replaceAllUsesWith(SourceVal);
+ I->eraseFromParent();
+ if (Y->use_empty())
+ Y->eraseFromParent();
+
+ return true;
+}
+
+bool SVEIntrinsicOpts::optimizeIntrinsic(Instruction *I) {
+ IntrinsicInst *IntrI = dyn_cast<IntrinsicInst>(I);
+ if (!IntrI)
+ return false;
+
+ switch (IntrI->getIntrinsicID()) {
+ case Intrinsic::aarch64_sve_convert_from_svbool:
+ return optimizeConvertFromSVBool(IntrI);
+ case Intrinsic::aarch64_sve_ptest_any:
+ case Intrinsic::aarch64_sve_ptest_first:
+ case Intrinsic::aarch64_sve_ptest_last:
+ return optimizePTest(IntrI);
+ default:
+ return false;
+ }
+
+ return true;
+}
+
+bool SVEIntrinsicOpts::optimizeFunctions(
+ SmallSetVector<Function *, 4> &Functions) {
+ bool Changed = false;
+ for (auto *F : Functions) {
+ DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>(*F).getDomTree();
+
+ // Traverse the DT with an rpo walk so we see defs before uses, allowing
+ // simplification to be done incrementally.
+ BasicBlock *Root = DT->getRoot();
+ ReversePostOrderTraversal<BasicBlock *> RPOT(Root);
+ for (auto *BB : RPOT)
+ for (Instruction &I : make_early_inc_range(*BB))
+ Changed |= optimizeIntrinsic(&I);
+ }
+ return Changed;
+}
+
+bool SVEIntrinsicOpts::runOnModule(Module &M) {
+ bool Changed = false;
+ SmallSetVector<Function *, 4> Functions;
+
+ // Check for SVE intrinsic declarations first so that we only iterate over
+ // relevant functions. Where an appropriate declaration is found, store the
+ // function(s) where it is used so we can target these only.
+ for (auto &F : M.getFunctionList()) {
+ if (!F.isDeclaration())
+ continue;
+
+ switch (F.getIntrinsicID()) {
+ case Intrinsic::aarch64_sve_convert_from_svbool:
+ case Intrinsic::aarch64_sve_ptest_any:
+ case Intrinsic::aarch64_sve_ptest_first:
+ case Intrinsic::aarch64_sve_ptest_last:
+ for (auto I = F.user_begin(), E = F.user_end(); I != E;) {
+ auto *Inst = dyn_cast<Instruction>(*I++);
+ Functions.insert(Inst->getFunction());
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ if (!Functions.empty())
+ Changed |= optimizeFunctions(Functions);
+
+ return Changed;
+}
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