[llvm] [SLP][modularisation][NFC] Move isFirstInsertElement/getDebugLocFromPHI to SLPUtils (PR #222612)

[Madhur Amilkanthwar via llvm-commits]

https://github.com/madhur13490 created https://github.com/llvm/llvm-project/pull/222612

Move the BoUpSLP-independent helpers isFirstInsertElement and
getDebugLocFromPHI out of SLPVectorizer.cpp into the self-contained
SLPVectorizer/SLPUtils.{h,cpp} module.

Part of the SLPVectorizer.cpp modularization effort:
https://discourse.llvm.org/t/modularizing-slpvectorizer-cpp/90922

>From e46c2db12bbbabacc71a8ace6c5fd3abda74514f Mon Sep 17 00:00:00 2001
From: Madhur Amilkanthwar <madhura at nvidia.com>
Date: Thu, 10 Sep 2026 04:08:12 -0700
Subject: [PATCH] [SLP][modularisation][NFC] Move
 isFirstInsertElement/getDebugLocFromPHI to SLPUtils

Move the BoUpSLP-independent helpers isFirstInsertElement and
getDebugLocFromPHI out of SLPVectorizer.cpp into the self-contained
SLPVectorizer/SLPUtils.{h,cpp} module.

Part of the SLPVectorizer.cpp modularization effort:
https://discourse.llvm.org/t/modularizing-slpvectorizer-cpp/90922
---
 .../Transforms/Vectorize/SLPVectorizer.cpp    | 33 ------------------
 .../Vectorize/SLPVectorizer/SLPUtils.cpp      | 34 +++++++++++++++++++
 .../Vectorize/SLPVectorizer/SLPUtils.h        | 12 +++++++
 3 files changed, 46 insertions(+), 33 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 3fd146320c959..ee9ad7fc43973 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -18076,33 +18076,6 @@ InstructionCost BoUpSLP::getSpillCost() {
 
 /// Checks if the \p IE1 instructions is followed by \p IE2 instruction in the
 /// buildvector sequence.
-static bool isFirstInsertElement(const InsertElementInst *IE1,
-                                 const InsertElementInst *IE2) {
-  if (IE1 == IE2)
-    return false;
-  const auto *I1 = IE1;
-  const auto *I2 = IE2;
-  const InsertElementInst *PrevI1;
-  const InsertElementInst *PrevI2;
-  unsigned Idx1 = *getElementIndex(IE1);
-  unsigned Idx2 = *getElementIndex(IE2);
-  do {
-    if (I2 == IE1)
-      return true;
-    if (I1 == IE2)
-      return false;
-    PrevI1 = I1;
-    PrevI2 = I2;
-    if (I1 && (I1 == IE1 || I1->hasOneUse()) &&
-        getElementIndex(I1).value_or(Idx2) != Idx2)
-      I1 = dyn_cast<InsertElementInst>(I1->getOperand(0));
-    if (I2 && ((I2 == IE2 || I2->hasOneUse())) &&
-        getElementIndex(I2).value_or(Idx1) != Idx1)
-      I2 = dyn_cast<InsertElementInst>(I2->getOperand(0));
-  } while ((I1 && PrevI1 != I1) || (I2 && PrevI2 != I2));
-  llvm_unreachable("Two different buildvectors not expected.");
-}
-
 namespace {
 /// Returns incoming Value *, if the requested type is Value * too, or a default
 /// value, otherwise.
@@ -22380,12 +22353,6 @@ static Instruction *propagateMetadata(Instruction *Inst, ArrayRef<Value *> VL) {
   return llvm::propagateMetadata(Inst, Insts);
 }
 
-static DebugLoc getDebugLocFromPHI(PHINode &PN) {
-  if (DebugLoc DL = PN.getDebugLoc())
-    return DL;
-  return DebugLoc::getUnknown();
-}
-
 Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
   IRBuilderBase::InsertPointGuard Guard(Builder);
 
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.cpp
index e7d5498c757e4..56915bda370cf 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.cpp
@@ -16,6 +16,7 @@
 #include "llvm/Analysis/VectorUtils.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugLoc.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
@@ -1139,4 +1140,37 @@ TargetTransformInfo::TargetCostKind getSLPCostKind(const Function *F) {
   return F->hasOptSize() ? TTI::TCK_CodeSize : TTI::TCK_RecipThroughput;
 }
 
+bool isFirstInsertElement(const InsertElementInst *IE1,
+                          const InsertElementInst *IE2) {
+  if (IE1 == IE2)
+    return false;
+  const auto *I1 = IE1;
+  const auto *I2 = IE2;
+  const InsertElementInst *PrevI1;
+  const InsertElementInst *PrevI2;
+  unsigned Idx1 = *getElementIndex(IE1);
+  unsigned Idx2 = *getElementIndex(IE2);
+  do {
+    if (I2 == IE1)
+      return true;
+    if (I1 == IE2)
+      return false;
+    PrevI1 = I1;
+    PrevI2 = I2;
+    if (I1 && (I1 == IE1 || I1->hasOneUse()) &&
+        getElementIndex(I1).value_or(Idx2) != Idx2)
+      I1 = dyn_cast<InsertElementInst>(I1->getOperand(0));
+    if (I2 && ((I2 == IE2 || I2->hasOneUse())) &&
+        getElementIndex(I2).value_or(Idx1) != Idx1)
+      I2 = dyn_cast<InsertElementInst>(I2->getOperand(0));
+  } while ((I1 && PrevI1 != I1) || (I2 && PrevI2 != I2));
+  llvm_unreachable("Two different buildvectors not expected.");
+}
+
+DebugLoc getDebugLocFromPHI(PHINode &PN) {
+  if (DebugLoc DL = PN.getDebugLoc())
+    return DL;
+  return DebugLoc::getUnknown();
+}
+
 } // namespace llvm::slpvectorizer
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.h b/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.h
index 91340ac0d07c6..f319b1aea7e5a 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.h
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer/SLPUtils.h
@@ -32,8 +32,11 @@ namespace llvm {
 class AssumptionCache;
 class Constant;
 class DataLayout;
+class DebugLoc;
 class Instruction;
+class InsertElementInst;
 class IRBuilderBase;
+class PHINode;
 class TargetLibraryInfo;
 class Type;
 class Value;
@@ -411,6 +414,15 @@ void collectNarrowedLeaves(Value *V, unsigned RdxOpcode, unsigned WideBW,
 
 TargetTransformInfo::TargetCostKind getSLPCostKind(const Function *F);
 
+/// \returns true if \p IE1 appears before \p IE2 in the same insertelement
+/// build-vector chain.
+bool isFirstInsertElement(const InsertElementInst *IE1,
+                          const InsertElementInst *IE2);
+
+/// \returns the debug location of \p PN, or an unknown location if it has
+/// none.
+DebugLoc getDebugLocFromPHI(PHINode &PN);
+
 } // namespace llvm::slpvectorizer
 
 #endif // LLVM_LIB_TRANSFORMS_VECTORIZE_SLPVECTORIZER_SLPUTILS_H