[llvm] [SandboxVectorizer] Register erase callback for seed collection (PR #115951)

[via llvm-commits]

https://github.com/Sterling-Augustine updated https://github.com/llvm/llvm-project/pull/115951

>From f35a46729c2d2f2c4caf82222eedfffc96621e23 Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Tue, 12 Nov 2024 14:32:57 -0800
Subject: [PATCH 1/2] [SandboxVectorizer] Register erase instruction callbacks
 for seed collection

---
 .../Vectorize/SandboxVectorizer/SeedCollector.h   |  7 ++++++-
 .../Vectorize/SandboxVectorizer/SeedCollector.cpp | 13 +++++++++----
 .../SandboxVectorizer/SeedCollectorTest.cpp       | 15 +++++++++++++++
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
index ed1cb8488c29eb..958ec673b60164 100644
--- a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
+++ b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
@@ -223,6 +223,11 @@ class SeedContainer {
     /// Note that the bundles themselves may have additional ordering, created
     /// by the subclasses by insertAt. The bundles themselves may also have used
     /// instructions.
+
+    // TODO: Range_size counts fully used-bundles. Further, iterating over
+    // anything other than the Bundles in a SeedContainer includes used seeds,
+    // so for now just check that removing all the seeds from a bundle also
+    // empties the bundle. Rework the iterator logic to clean this up.
     iterator(BundleMapT &Map, BundleMapT::iterator MapIt, ValT *Vec, int VecIdx)
         : Map(&Map), MapIt(MapIt), Vec(Vec), VecIdx(VecIdx) {}
     value_type &operator*() {
@@ -288,7 +293,7 @@ class SeedCollector {
   SeedContainer StoreSeeds;
   SeedContainer LoadSeeds;
   Context &Ctx;
-
+  Context::CallbackID EraseCallbackID;
   /// \Returns the number of SeedBundle groups for all seed types.
   /// This is to be used for limiting compilation time.
   unsigned totalNumSeedGroups() const {
diff --git a/llvm/lib/Transforms/Vectorize/SandboxVectorizer/SeedCollector.cpp b/llvm/lib/Transforms/Vectorize/SandboxVectorizer/SeedCollector.cpp
index 1dbdd80117563c..17544afcc185fd 100644
--- a/llvm/lib/Transforms/Vectorize/SandboxVectorizer/SeedCollector.cpp
+++ b/llvm/lib/Transforms/Vectorize/SandboxVectorizer/SeedCollector.cpp
@@ -159,13 +159,19 @@ template bool isValidMemSeed<StoreInst>(StoreInst *LSI);
 
 SeedCollector::SeedCollector(BasicBlock *BB, ScalarEvolution &SE)
     : StoreSeeds(SE), LoadSeeds(SE), Ctx(BB->getContext()) {
-  // TODO: Register a callback for updating the Collector data structures upon
-  // instr removal
 
   bool CollectStores = CollectSeeds.find(StoreSeedsDef) != std::string::npos;
   bool CollectLoads = CollectSeeds.find(LoadSeedsDef) != std::string::npos;
   if (!CollectStores && !CollectLoads)
     return;
+
+  EraseCallbackID = Ctx.registerEraseInstrCallback([this](Instruction *I) {
+    if (auto SI = dyn_cast<StoreInst>(I))
+      StoreSeeds.erase(SI);
+    else if (auto LI = dyn_cast<LoadInst>(I))
+      LoadSeeds.erase(LI);
+  });
+
   // Actually collect the seeds.
   for (auto &I : *BB) {
     if (StoreInst *SI = dyn_cast<StoreInst>(&I))
@@ -181,8 +187,7 @@ SeedCollector::SeedCollector(BasicBlock *BB, ScalarEvolution &SE)
 }
 
 SeedCollector::~SeedCollector() {
-  // TODO: Unregister the callback for updating the seed datastructures upon
-  // instr removal
+  Ctx.unregisterEraseInstrCallback(EraseCallbackID);
 }
 
 #ifndef NDEBUG
diff --git a/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp b/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
index b1b0156a4fe31a..4fc44f9fddc9a8 100644
--- a/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
@@ -374,6 +374,21 @@ define void @foo(ptr noalias %ptr, float %val) {
   // Expect just one vector of store seeds
   EXPECT_EQ(range_size(StoreSeedsRange), 1u);
   ExpectThatElementsAre(SB, {St0, St1, St2, St3});
+  // Check that the EraseInstr callback works.  TODO: Range_size counts fully
+  // used-bundles even though the iterator skips them. Further, iterating over
+  // anything other than the Bundles in a SeedContainer includes used seeds.  So
+  // for now just check that removing all the seeds from a bundle also empties
+  // the bundle.
+  St0->eraseFromParent();
+  St1->eraseFromParent();
+  St2->eraseFromParent();
+  St3->eraseFromParent();
+  size_t nonEmptyBundleCount = 0;
+  for (auto &B : SC.getStoreSeeds()) {
+    (void)B;
+    nonEmptyBundleCount++;
+  }
+  EXPECT_EQ(nonEmptyBundleCount, 0u);
 }
 
 TEST_F(SeedBundleTest, VectorStores) {

>From ed034eaa9b42fc0a3723625a51402e095a39a56f Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Tue, 12 Nov 2024 15:42:09 -0800
Subject: [PATCH 2/2] Address comments

---
 .../Vectorize/SandboxVectorizer/SeedCollector.h       |  5 ++---
 .../Vectorize/SandboxVectorizer/SeedCollectorTest.cpp | 11 ++++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
index 958ec673b60164..6e16a84d832e5e 100644
--- a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
+++ b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/SeedCollector.h
@@ -225,9 +225,8 @@ class SeedContainer {
     /// instructions.
 
     // TODO: Range_size counts fully used-bundles. Further, iterating over
-    // anything other than the Bundles in a SeedContainer includes used seeds,
-    // so for now just check that removing all the seeds from a bundle also
-    // empties the bundle. Rework the iterator logic to clean this up.
+    // anything other than the Bundles in a SeedContainer includes used
+    // seeds. Rework the iterator logic to clean this up.
     iterator(BundleMapT &Map, BundleMapT::iterator MapIt, ValT *Vec, int VecIdx)
         : Map(&Map), MapIt(MapIt), Vec(Vec), VecIdx(VecIdx) {}
     value_type &operator*() {
diff --git a/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp b/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
index 4fc44f9fddc9a8..95a8f66ac1e662 100644
--- a/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/SandboxVectorizer/SeedCollectorTest.cpp
@@ -374,11 +374,12 @@ define void @foo(ptr noalias %ptr, float %val) {
   // Expect just one vector of store seeds
   EXPECT_EQ(range_size(StoreSeedsRange), 1u);
   ExpectThatElementsAre(SB, {St0, St1, St2, St3});
-  // Check that the EraseInstr callback works.  TODO: Range_size counts fully
-  // used-bundles even though the iterator skips them. Further, iterating over
-  // anything other than the Bundles in a SeedContainer includes used seeds.  So
-  // for now just check that removing all the seeds from a bundle also empties
-  // the bundle.
+  // Check that the EraseInstr callback works.
+
+  // TODO: Range_size counts fully used-bundles even though the iterator skips
+  // them. Further, iterating over anything other than the Bundles in a
+  // SeedContainer includes used seeds. So for now just check that removing all
+  // the seeds from a bundle also empties the bundle.
   St0->eraseFromParent();
   St1->eraseFromParent();
   St2->eraseFromParent();