[SandboxVec] Notify scheduler about new instructions

This patch registers the "createInstr" callback that notifies the scheduler
about newly created instructions. This guarantees that all newly created
instructions have a corresponding DAG node associated with them.
Without this the pass crashes when the scheduler encounters the newly
created vector instructions.

This patch also changes the lifetime of the sandboxir Ctx variable
in the SandboxVectorizer pass. It needs to be destroyed after the passes
get destroyed. Without this change when components like the Scheduler get
destroyed Ctx will have already been freed, which is not legal.

Author: Vasileios Porpodas

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h

@@ -345,6 +345,11 @@ class DependencyGraph {
   Interval<Instruction> extend(ArrayRef<Instruction *> Instrs);
   /// \Returns the range of instructions included in the DAG.
   Interval<Instruction> getInterval() const { return DAGInterval; }
+  /// Called by the scheduler when a new instruction \p I has been created.
+  void notifyCreateInstr(Instruction *I) {
+    getOrCreateNode(I);
+    // TODO: Update the dependencies for the new node.
+  }
 #ifndef NDEBUG
   void print(raw_ostream &OS) const;
   LLVM_DUMP_METHOD void dump() const;

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Legality.h

@@ -162,8 +162,9 @@ class LegalityAnalysis {
   const DataLayout &DL;
 
 public:
-  LegalityAnalysis(AAResults &AA, ScalarEvolution &SE, const DataLayout &DL)
-      : Sched(AA), SE(SE), DL(DL) {}
+  LegalityAnalysis(AAResults &AA, ScalarEvolution &SE, const DataLayout &DL,
+                   Context &Ctx)
+      : Sched(AA, Ctx), SE(SE), DL(DL) {}
   /// A LegalityResult factory.
   template <typename ResultT, typename... ArgsT>
   ResultT &createLegalityResult(ArgsT... Args) {

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizer.h

@@ -13,6 +13,7 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/SandboxIR/Context.h"
 #include "llvm/SandboxIR/PassManager.h"
 
 namespace llvm {
@@ -24,6 +25,8 @@ class SandboxVectorizerPass : public PassInfoMixin<SandboxVectorizerPass> {
   AAResults *AA = nullptr;
   ScalarEvolution *SE = nullptr;
 
+  std::unique_ptr<sandboxir::Context> Ctx;
+
   // A pipeline of SandboxIR function passes run by the vectorizer.
   sandboxir::FunctionPassManager FPM;
 

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Scheduler.h

@@ -95,6 +95,8 @@ class Scheduler {
   DependencyGraph DAG;
   std::optional<BasicBlock::iterator> ScheduleTopItOpt;
   SmallVector<std::unique_ptr<SchedBundle>> Bndls;
+  Context &Ctx;
+  Context::CallbackID CreateInstrCB;
 
   /// \Returns a scheduling bundle containing \p Instrs.
   SchedBundle *createBundle(ArrayRef<Instruction *> Instrs);
@@ -110,8 +112,11 @@ class Scheduler {
   Scheduler &operator=(const Scheduler &) = delete;
 
 public:
-  Scheduler(AAResults &AA) : DAG(AA) {}
-  ~Scheduler() {}
+  Scheduler(AAResults &AA, Context &Ctx) : DAG(AA), Ctx(Ctx) {
+    CreateInstrCB = Ctx.registerCreateInstrCallback(
+        [this](Instruction *I) { DAG.notifyCreateInstr(I); });
+  }
+  ~Scheduler() { Ctx.unregisterCreateInstrCallback(CreateInstrCB); }
 
   bool trySchedule(ArrayRef<Instruction *> Instrs);
 

llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp

@@ -182,8 +182,6 @@ Value *BottomUpVec::vectorizeRec(ArrayRef<Value *> Bndl) {
     }
     NewVec = createVectorInstr(Bndl, VecOperands);
 
-    // TODO: Notify DAG/Scheduler about new instruction
-
     // TODO: Collect potentially dead instructions.
     break;
   }
@@ -202,7 +200,8 @@ bool BottomUpVec::tryVectorize(ArrayRef<Value *> Bndl) {
 
 bool BottomUpVec::runOnFunction(Function &F, const Analyses &A) {
   Legality = std::make_unique<LegalityAnalysis>(
-      A.getAA(), A.getScalarEvolution(), F.getParent()->getDataLayout());
+      A.getAA(), A.getScalarEvolution(), F.getParent()->getDataLayout(),
+      F.getContext());
   Change = false;
   // TODO: Start from innermost BBs first
   for (auto &BB : F) {

llvm/lib/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizer.cpp

@@ -64,6 +64,9 @@ PreservedAnalyses SandboxVectorizerPass::run(Function &F,
 }
 
 bool SandboxVectorizerPass::runImpl(Function &LLVMF) {
+  if (Ctx == nullptr)
+    Ctx = std::make_unique<sandboxir::Context>(LLVMF.getContext());
+
   if (PrintPassPipeline) {
     FPM.printPipeline(outs());
     return false;
@@ -82,8 +85,7 @@ bool SandboxVectorizerPass::runImpl(Function &LLVMF) {
   }
 
   // Create SandboxIR for LLVMF and run BottomUpVec on it.
-  sandboxir::Context Ctx(LLVMF.getContext());
-  sandboxir::Function &F = *Ctx.createFunction(&LLVMF);
+  sandboxir::Function &F = *Ctx->createFunction(&LLVMF);
   sandboxir::Analyses A(*AA, *SE);
   return FPM.runOnFunction(F, A);
 }

llvm/test/Transforms/SandboxVectorizer/bottomup_basic.ll

@@ -55,7 +55,46 @@ define void @store_fpext_load(ptr %ptr) {
   ret void
 }
 
-; TODO: Test store_zext_fcmp_load once we implement scheduler callbacks and legality diamond check
+define void @store_fcmp_zext_load(ptr %ptr) {
+; CHECK-LABEL: define void @store_fcmp_zext_load(
+; CHECK-SAME: ptr [[PTR:%.*]]) {
+; CHECK-NEXT:    [[PTR0:%.*]] = getelementptr float, ptr [[PTR]], i32 0
+; CHECK-NEXT:    [[PTR1:%.*]] = getelementptr float, ptr [[PTR]], i32 1
+; CHECK-NEXT:    [[PTRB0:%.*]] = getelementptr i32, ptr [[PTR]], i32 0
+; CHECK-NEXT:    [[PTRB1:%.*]] = getelementptr i32, ptr [[PTR]], i32 1
+; CHECK-NEXT:    [[LDB0:%.*]] = load float, ptr [[PTR0]], align 4
+; CHECK-NEXT:    [[LDB1:%.*]] = load float, ptr [[PTR1]], align 4
+; CHECK-NEXT:    [[VECL1:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
+; CHECK-NEXT:    [[LDA0:%.*]] = load float, ptr [[PTR0]], align 4
+; CHECK-NEXT:    [[LDA1:%.*]] = load float, ptr [[PTR1]], align 4
+; CHECK-NEXT:    [[VECL:%.*]] = load <2 x float>, ptr [[PTR0]], align 4
+; CHECK-NEXT:    [[FCMP0:%.*]] = fcmp ogt float [[LDA0]], [[LDB0]]
+; CHECK-NEXT:    [[FCMP1:%.*]] = fcmp ogt float [[LDA1]], [[LDB1]]
+; CHECK-NEXT:    [[VCMP:%.*]] = fcmp ogt <2 x float> [[VECL]], [[VECL1]]
+; CHECK-NEXT:    [[ZEXT0:%.*]] = zext i1 [[FCMP0]] to i32
+; CHECK-NEXT:    [[ZEXT1:%.*]] = zext i1 [[FCMP1]] to i32
+; CHECK-NEXT:    [[VCAST:%.*]] = zext <2 x i1> [[VCMP]] to <2 x i32>
+; CHECK-NEXT:    store i32 [[ZEXT0]], ptr [[PTRB0]], align 4
+; CHECK-NEXT:    store i32 [[ZEXT1]], ptr [[PTRB1]], align 4
+; CHECK-NEXT:    store <2 x i32> [[VCAST]], ptr [[PTRB0]], align 4
+; CHECK-NEXT:    ret void
+;
+  %ptr0 = getelementptr float, ptr %ptr, i32 0
+  %ptr1 = getelementptr float, ptr %ptr, i32 1
+  %ptrb0 = getelementptr i32, ptr %ptr, i32 0
+  %ptrb1 = getelementptr i32, ptr %ptr, i32 1
+  %ldB0 = load float, ptr %ptr0
+  %ldB1 = load float, ptr %ptr1
+  %ldA0 = load float, ptr %ptr0
+  %ldA1 = load float, ptr %ptr1
+  %fcmp0 = fcmp ogt float %ldA0, %ldB0
+  %fcmp1 = fcmp ogt float %ldA1, %ldB1
+  %zext0 = zext i1 %fcmp0 to i32
+  %zext1 = zext i1 %fcmp1 to i32
+  store i32 %zext0, ptr %ptrb0
+  store i32 %zext1, ptr %ptrb1
+  ret void
+}
 
 ; TODO: Test store_fadd_load once we implement scheduler callbacks and legality diamond check
 

llvm/unittests/Transforms/Vectorize/SandboxVectorizer/LegalityTest.cpp

@@ -110,7 +110,7 @@ define void @foo(ptr %ptr, <2 x float> %vec2, <3 x float> %vec3, i8 %arg, float
   auto *CmpSLT = cast<sandboxir::CmpInst>(&*It++);
   auto *CmpSGT = cast<sandboxir::CmpInst>(&*It++);
 
-  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL);
+  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL, Ctx);
   const auto &Result =
       Legality.canVectorize({St0, St1}, /*SkipScheduling=*/true);
   EXPECT_TRUE(isa<sandboxir::Widen>(Result));
@@ -228,7 +228,7 @@ define void @foo(ptr %ptr) {
   auto *St0 = cast<sandboxir::StoreInst>(&*It++);
   auto *St1 = cast<sandboxir::StoreInst>(&*It++);
 
-  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL);
+  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL, Ctx);
   {
     // Can vectorize St0,St1.
     const auto &Result = Legality.canVectorize({St0, St1});
@@ -262,7 +262,8 @@ define void @foo() {
     return Buff == ExpectedStr;
   };
 
-  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL);
+  sandboxir::Context Ctx(C);
+  sandboxir::LegalityAnalysis Legality(*AA, *SE, DL, Ctx);
   EXPECT_TRUE(
       Matches(Legality.createLegalityResult<sandboxir::Widen>(), "Widen"));
   EXPECT_TRUE(Matches(Legality.createLegalityResult<sandboxir::Pack>(

llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SchedulerTest.cpp

@@ -156,20 +156,20 @@ define void @foo(ptr %ptr, i8 %v0, i8 %v1) {
 
   {
     // Schedule all instructions in sequence.
-    sandboxir::Scheduler Sched(getAA(*LLVMF));
+    sandboxir::Scheduler Sched(getAA(*LLVMF), Ctx);
     EXPECT_TRUE(Sched.trySchedule({Ret}));
     EXPECT_TRUE(Sched.trySchedule({S1}));
     EXPECT_TRUE(Sched.trySchedule({S0}));
   }
   {
     // Skip instructions.
-    sandboxir::Scheduler Sched(getAA(*LLVMF));
+    sandboxir::Scheduler Sched(getAA(*LLVMF), Ctx);
     EXPECT_TRUE(Sched.trySchedule({Ret}));
     EXPECT_TRUE(Sched.trySchedule({S0}));
   }
   {
     // Try invalid scheduling
-    sandboxir::Scheduler Sched(getAA(*LLVMF));
+    sandboxir::Scheduler Sched(getAA(*LLVMF), Ctx);
     EXPECT_TRUE(Sched.trySchedule({Ret}));
     EXPECT_TRUE(Sched.trySchedule({S0}));
     EXPECT_FALSE(Sched.trySchedule({S1}));
@@ -197,7 +197,7 @@ define void @foo(ptr noalias %ptr0, ptr noalias %ptr1) {
   auto *S1 = cast<sandboxir::StoreInst>(&*It++);
   auto *Ret = cast<sandboxir::ReturnInst>(&*It++);
 
-  sandboxir::Scheduler Sched(getAA(*LLVMF));
+  sandboxir::Scheduler Sched(getAA(*LLVMF), Ctx);
   EXPECT_TRUE(Sched.trySchedule({Ret}));
   EXPECT_TRUE(Sched.trySchedule({S0, S1}));
   EXPECT_TRUE(Sched.trySchedule({L0, L1}));