1//===- LowerVectorIntrinsics.cpp ------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "llvm/Transforms/Utils/LowerVectorIntrinsics.h"
10#include "llvm/IR/IRBuilder.h"
11#include "llvm/IR/Module.h"
12
13#define DEBUG_TYPE "lower-vector-intrinsics"
14
15using namespace llvm;
16
17bool llvm::lowerUnaryVectorIntrinsicAsLoop(Module &M, CallInst *CI) {
18 Type *ArgTy = CI->getArgOperand(i: 0)->getType();
19 VectorType *VecTy = cast<VectorType>(Val: ArgTy);
20
21 BasicBlock *PreLoopBB = CI->getParent();
22 BasicBlock *PostLoopBB = nullptr;
23 Function *ParentFunc = PreLoopBB->getParent();
24 LLVMContext &Ctx = PreLoopBB->getContext();
25 Type *IdxTy = M.getDataLayout().getIndexType(C&: Ctx, AddressSpace: 0);
26
27 PostLoopBB = PreLoopBB->splitBasicBlock(I: CI);
28 BasicBlock *LoopBB = BasicBlock::Create(Context&: Ctx, Name: "", Parent: ParentFunc, InsertBefore: PostLoopBB);
29 PreLoopBB->getTerminator()->setSuccessor(Idx: 0, BB: LoopBB);
30
31 // Loop preheader
32 IRBuilder<> PreLoopBuilder(PreLoopBB->getTerminator());
33 Value *LoopEnd =
34 PreLoopBuilder.CreateElementCount(Ty: IdxTy, EC: VecTy->getElementCount());
35
36 // Loop body
37 IRBuilder<> LoopBuilder(LoopBB);
38
39 PHINode *LoopIndex = LoopBuilder.CreatePHI(Ty: IdxTy, NumReservedValues: 2);
40 LoopIndex->addIncoming(V: ConstantInt::get(Ty: IdxTy, V: 0U), BB: PreLoopBB);
41 PHINode *Vec = LoopBuilder.CreatePHI(Ty: VecTy, NumReservedValues: 2);
42 Vec->addIncoming(V: CI->getArgOperand(i: 0), BB: PreLoopBB);
43
44 Value *Elem = LoopBuilder.CreateExtractElement(Vec, Idx: LoopIndex);
45 Function *Exp = Intrinsic::getOrInsertDeclaration(M: &M, id: CI->getIntrinsicID(),
46 OverloadTys: VecTy->getElementType());
47 Value *Res = LoopBuilder.CreateCall(Callee: Exp, Args: Elem);
48 Value *NewVec = LoopBuilder.CreateInsertElement(Vec, NewElt: Res, Idx: LoopIndex);
49 Vec->addIncoming(V: NewVec, BB: LoopBB);
50
51 Value *One = ConstantInt::get(Ty: IdxTy, V: 1U);
52 Value *NextLoopIndex = LoopBuilder.CreateAdd(LHS: LoopIndex, RHS: One);
53 LoopIndex->addIncoming(V: NextLoopIndex, BB: LoopBB);
54
55 Value *ExitCond =
56 LoopBuilder.CreateICmp(P: CmpInst::ICMP_EQ, LHS: NextLoopIndex, RHS: LoopEnd);
57 LoopBuilder.CreateCondBr(Cond: ExitCond, True: PostLoopBB, False: LoopBB);
58
59 CI->replaceAllUsesWith(V: NewVec);
60 CI->eraseFromParent();
61 return true;
62}
63