[llvm-branch-commits] [llvm] [IR2Vec] Consider only reachable BBs and non-debug instructions (PR #143476)

[S. VenkataKeerthy via llvm-branch-commits]

https://github.com/svkeerthy updated https://github.com/llvm/llvm-project/pull/143476

>From 173c3b1479f50923429d02e7cd666d3d033f0d65 Mon Sep 17 00:00:00 2001
From: svkeerthy <venkatakeerthy at google.com>
Date: Tue, 10 Jun 2025 04:49:59 +0000
Subject: [PATCH] reachable BB

---
 llvm/lib/Analysis/IR2Vec.cpp             | 13 +++++---
 llvm/test/Analysis/IR2Vec/dbg-inst.ll    | 13 ++++++++
 llvm/test/Analysis/IR2Vec/unreachable.ll | 42 ++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 4 deletions(-)
 create mode 100644 llvm/test/Analysis/IR2Vec/dbg-inst.ll
 create mode 100644 llvm/test/Analysis/IR2Vec/unreachable.ll

diff --git a/llvm/lib/Analysis/IR2Vec.cpp b/llvm/lib/Analysis/IR2Vec.cpp
index 0f7303c1b0917..fa38c35796a0e 100644
--- a/llvm/lib/Analysis/IR2Vec.cpp
+++ b/llvm/lib/Analysis/IR2Vec.cpp
@@ -13,7 +13,9 @@
 
 #include "llvm/Analysis/IR2Vec.h"
 
+#include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/IR/CFG.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/Debug.h"
@@ -190,7 +192,8 @@ Embedding SymbolicEmbedder::getOperandEmbedding(const Value *Op) const {
 void SymbolicEmbedder::computeEmbeddings(const BasicBlock &BB) const {
   Embedding BBVector(Dimension, 0);
 
-  for (const auto &I : BB) {
+  // We consider only the non-debug and non-pseudo instructions
+  for (const auto &I : BB.instructionsWithoutDebug()) {
     Embedding InstVector(Dimension, 0);
 
     const auto OpcVec = lookupVocab(I.getOpcodeName());
@@ -215,9 +218,11 @@ void SymbolicEmbedder::computeEmbeddings(const BasicBlock &BB) const {
 void SymbolicEmbedder::computeEmbeddings() const {
   if (F.isDeclaration())
     return;
-  for (const auto &BB : F) {
-    computeEmbeddings(BB);
-    FuncVector += BBVecMap[&BB];
+
+  // Consider only the basic blocks that are reachable from entry
+  for (const BasicBlock *BB : depth_first(&F)) {
+    computeEmbeddings(*BB);
+    FuncVector += BBVecMap[BB];
   }
 }
 
diff --git a/llvm/test/Analysis/IR2Vec/dbg-inst.ll b/llvm/test/Analysis/IR2Vec/dbg-inst.ll
new file mode 100644
index 0000000000000..0f486b0ba6a52
--- /dev/null
+++ b/llvm/test/Analysis/IR2Vec/dbg-inst.ll
@@ -0,0 +1,13 @@
+; RUN: opt -passes='print<ir2vec>' -o /dev/null -ir2vec-vocab-path=%S/Inputs/dummy_3D_vocab.json %s 2>&1 | FileCheck %s
+
+define void @bar2(ptr %foo)  {
+  store i32 0, ptr %foo, align 4
+  tail call void @llvm.dbg.value(metadata !{}, i64 0, metadata !{}, metadata !{})
+  ret void
+}
+
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnone
+
+; CHECK: Instruction vectors:
+; CHECK-NEXT: Instruction:   store i32 0, ptr %foo, align 4 [ 7.00  8.00  9.00 ]
+; CHECK-NEXT: Instruction:   ret void [ 0.00  0.00  0.00 ]
diff --git a/llvm/test/Analysis/IR2Vec/unreachable.ll b/llvm/test/Analysis/IR2Vec/unreachable.ll
new file mode 100644
index 0000000000000..370fe6881d6ce
--- /dev/null
+++ b/llvm/test/Analysis/IR2Vec/unreachable.ll
@@ -0,0 +1,42 @@
+; RUN: opt -passes='print<ir2vec>' -o /dev/null -ir2vec-vocab-path=%S/Inputs/dummy_3D_vocab.json %s 2>&1 | FileCheck %s
+
+define dso_local i32 @abc(i32 noundef %a, i32 noundef %b) #0 {
+entry:
+  %retval = alloca i32, align 4
+  %a.addr = alloca i32, align 4
+  %b.addr = alloca i32, align 4
+  store i32 %a, ptr %a.addr, align 4
+  store i32 %b, ptr %b.addr, align 4
+  %0 = load i32, ptr %a.addr, align 4
+  %1 = load i32, ptr %b.addr, align 4
+  %cmp = icmp sgt i32 %0, %1
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %2 = load i32, ptr %b.addr, align 4
+  store i32 %2, ptr %retval, align 4
+  br label %return
+
+if.else:                                          ; preds = %entry
+  %3 = load i32, ptr %a.addr, align 4
+  store i32 %3, ptr %retval, align 4
+  br label %return
+
+unreachable:                                      ; Unreachable
+  store i32 0, ptr %retval, align 4
+  br label %return
+
+return:                                           ; preds = %if.else, %if.then
+  %4 = load i32, ptr %retval, align 4
+  ret i32 %4
+}
+
+; CHECK: Basic block vectors:
+; CHECK-NEXT: Basic block: entry:
+; CHECK-NEXT:  [ 25.00 32.00 39.00 ]
+; CHECK-NEXT: Basic block: if.then:
+; CHECK-NEXT:  [ 11.00 13.00 15.00 ]
+; CHECK-NEXT: Basic block: if.else:
+; CHECK-NEXT:  [ 11.00 13.00 15.00 ]
+; CHECK-NEXT: Basic block: return:
+; CHECK-NEXT:  [ 4.00 5.00 6.00 ]