b2edc0a3f8
fixes https://github.com/llvm/llvm-project/issues/129441 cc @lukel97 @badumbatish https://github.com/llvm/llvm-project/pull/145108 I've been learning a bit about LLVM, trying to make progress on some of these issues. The code below is based on https://github.com/llvm/llvm-project/pull/145108#issuecomment-3004561085, by implementing `shouldExpandReduction`. The implementation works for the test cases I added, but (obviously) fails for any existing cases. `ISD::VECREDUCE_AND` and `ISD::VECREDUCE_OR` are now marked as legal, which is required for the `Pat`s to fire, but when they don't that causes a selection failure. So, I'm wondering, what is the right approach here. Should I mark these intrinsics as `Custom` instead and manually perform the transformation in C++? Or is there some trick to still get the default lowering (a series of loads and scalar bitwise operations) when the patterns don't fire?
134 lines
3.5 KiB
C++
134 lines
3.5 KiB
C++
#include "WebAssembly.h"
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#include "WebAssemblySubtarget.h"
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#include "WebAssemblyTargetMachine.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/IntrinsicsWebAssembly.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Pass.h"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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namespace {
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struct WebAssemblyReduceToAnyAllTrue final : FunctionPass {
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static char ID;
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WebAssemblyTargetMachine &TM;
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const Module *CachedModule = nullptr;
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bool ModuleHasInterestingIntrinsics = false;
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WebAssemblyReduceToAnyAllTrue(WebAssemblyTargetMachine &TM)
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: FunctionPass(ID), TM(TM) {}
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StringRef getPassName() const override {
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return "WebAssembly convert reduce to any_true/all_true";
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}
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bool hasInterestingIntrinsics(const Module &M) {
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if (CachedModule == &M)
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return ModuleHasInterestingIntrinsics;
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CachedModule = &M;
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ModuleHasInterestingIntrinsics = false;
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for (const Function &Fn : M.functions()) {
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switch (Fn.getIntrinsicID()) {
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case Intrinsic::vector_reduce_or:
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case Intrinsic::vector_reduce_and:
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ModuleHasInterestingIntrinsics = true;
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return true;
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default:
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break;
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}
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}
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return false;
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}
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bool runOnFunction(Function &F) override {
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if (!TM.getSubtarget<WebAssemblySubtarget>(F).hasSIMD128())
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return false;
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if (!hasInterestingIntrinsics(*F.getParent()))
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return false;
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bool Changed = false;
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for (auto &BB : F) {
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for (auto It = BB.begin(), E = BB.end(); It != E;) {
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Instruction *I = &*It++;
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auto *Cmp = dyn_cast<ICmpInst>(I);
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if (!Cmp || Cmp->getPredicate() != ICmpInst::ICMP_NE)
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continue;
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Value *Reduce = nullptr;
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if (!match(Cmp, m_ICmp(m_Value(Reduce), m_ZeroInt())))
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continue;
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auto *II = dyn_cast<IntrinsicInst>(Reduce);
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if (!II || !II->hasOneUse())
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continue;
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IRBuilder<> B(Cmp);
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Value *Vec = II->getArgOperand(0);
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Module *M = F.getParent();
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auto makeIntrinsic = [&](Intrinsic::ID ID, Value *Arg) {
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Function *Fn =
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Intrinsic::getOrInsertDeclaration(M, ID, {Arg->getType()});
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return B.CreateCall(Fn, {Arg});
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};
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Value *New = nullptr;
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switch (II->getIntrinsicID()) {
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case Intrinsic::vector_reduce_or: {
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// reduce.or(X) != 0 -> anytrue(X)
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Value *Any = makeIntrinsic(Intrinsic::wasm_anytrue, Vec);
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New = B.CreateICmpNE(Any, ConstantInt::get(Any->getType(), 0));
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break;
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}
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case Intrinsic::vector_reduce_and: {
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// reduce.and(zext (icmp ne X, zeroinitializer)) != 0 -> alltrue(X)
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// Match: zext (icmp ne X, 0) from <N x i1> to <N x iX>
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CmpPredicate Pred;
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Value *LHS = nullptr;
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if (!match(Vec, m_ZExt(m_c_ICmp(Pred, m_Value(LHS), m_Zero()))))
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continue;
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if (Pred != ICmpInst::ICMP_NE)
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continue;
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Value *All = makeIntrinsic(Intrinsic::wasm_alltrue, LHS);
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New = B.CreateICmpNE(All, ConstantInt::get(All->getType(), 0));
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break;
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}
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default:
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continue;
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}
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Cmp->replaceAllUsesWith(New);
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Cmp->eraseFromParent();
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if (II->use_empty())
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II->eraseFromParent();
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Changed = true;
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}
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}
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return Changed;
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}
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};
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} // end anonymous namespace
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char WebAssemblyReduceToAnyAllTrue::ID = 0;
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FunctionPass *
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llvm::createWebAssemblyReduceToAnyAllTrue(WebAssemblyTargetMachine &TM) {
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return new WebAssemblyReduceToAnyAllTrue(TM);
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}
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