[llvm] [DA] Remove `DependenceInfo::unifySubscriptType` (PR #181607)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj updated https://github.com/llvm/llvm-project/pull/181607

>From e16fde12b6f35efad5ca1fe260cfd1ccba0a3224 Mon Sep 17 00:00:00 2001
From: Ryotaro Kasuga <kasuga.ryotaro at fujitsu.com>
Date: Mon, 16 Feb 2026 02:38:43 +0000
Subject: [PATCH] [DA] Remove `DependenceInfo::unifySubscriptType`

---
 .../llvm/Analysis/DependenceAnalysis.h        |  6 --
 llvm/lib/Analysis/DependenceAnalysis.cpp      | 57 ++-----------------
 2 files changed, 4 insertions(+), 59 deletions(-)

diff --git a/llvm/include/llvm/Analysis/DependenceAnalysis.h b/llvm/include/llvm/Analysis/DependenceAnalysis.h
index 528478ced1d9f..d4167bba6f1ac 100644
--- a/llvm/include/llvm/Analysis/DependenceAnalysis.h
+++ b/llvm/include/llvm/Analysis/DependenceAnalysis.h
@@ -472,12 +472,6 @@ class DependenceInfo {
   /// in LoopNest.
   bool isLoopInvariant(const SCEV *Expression, const Loop *LoopNest) const;
 
-  /// Makes sure all subscript pairs share the same integer type by
-  /// sign-extending as necessary.
-  /// Sign-extending a subscript is safe because getelementptr assumes the
-  /// array subscripts are signed.
-  void unifySubscriptType(ArrayRef<Subscript *> Pairs);
-
   /// collectCommonLoops - Finds the set of loops from the LoopNest that
   /// have a level <= CommonLevels and are referred to by the SCEV Expression.
   void collectCommonLoops(const SCEV *Expression, const Loop *LoopNest,
diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index f9eec7dfec169..465e745ec0367 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -1070,58 +1070,6 @@ void DependenceInfo::collectCommonLoops(const SCEV *Expression,
   }
 }
 
-void DependenceInfo::unifySubscriptType(ArrayRef<Subscript *> Pairs) {
-
-  unsigned widestWidthSeen = 0;
-  Type *widestType;
-
-  // Go through each pair and find the widest bit to which we need
-  // to extend all of them.
-  for (Subscript *Pair : Pairs) {
-    const SCEV *Src = Pair->Src;
-    const SCEV *Dst = Pair->Dst;
-    IntegerType *SrcTy = dyn_cast<IntegerType>(Src->getType());
-    IntegerType *DstTy = dyn_cast<IntegerType>(Dst->getType());
-    if (SrcTy == nullptr || DstTy == nullptr) {
-      assert(SrcTy == DstTy &&
-             "This function only unify integer types and "
-             "expect Src and Dst share the same type otherwise.");
-      continue;
-    }
-    if (SrcTy->getBitWidth() > widestWidthSeen) {
-      widestWidthSeen = SrcTy->getBitWidth();
-      widestType = SrcTy;
-    }
-    if (DstTy->getBitWidth() > widestWidthSeen) {
-      widestWidthSeen = DstTy->getBitWidth();
-      widestType = DstTy;
-    }
-  }
-
-  assert(widestWidthSeen > 0);
-
-  // Now extend each pair to the widest seen.
-  for (Subscript *Pair : Pairs) {
-    const SCEV *Src = Pair->Src;
-    const SCEV *Dst = Pair->Dst;
-    IntegerType *SrcTy = dyn_cast<IntegerType>(Src->getType());
-    IntegerType *DstTy = dyn_cast<IntegerType>(Dst->getType());
-    if (SrcTy == nullptr || DstTy == nullptr) {
-      assert(SrcTy == DstTy &&
-             "This function only unify integer types and "
-             "expect Src and Dst share the same type otherwise.");
-      continue;
-    }
-    if (SrcTy->getBitWidth() < widestWidthSeen)
-      // Sign-extend Src to widestType
-      Pair->Src = SE->getSignExtendExpr(Src, widestType);
-    if (DstTy->getBitWidth() < widestWidthSeen) {
-      // Sign-extend Dst to widestType
-      Pair->Dst = SE->getSignExtendExpr(Dst, widestType);
-    }
-  }
-}
-
 // Examine the scev and return true iff it's affine.
 // Collect any loops mentioned in the set of "Loops".
 bool DependenceInfo::checkSubscript(const SCEV *Expr, const Loop *LoopNest,
@@ -3263,7 +3211,10 @@ bool DependenceInfo::tryDelinearize(Instruction *Src, Instruction *Dst,
   for (int I = 0; I < Size; ++I) {
     Pair[I].Src = SrcSubscripts[I];
     Pair[I].Dst = DstSubscripts[I];
-    unifySubscriptType(&Pair[I]);
+
+    // TODO: Is this check necessary?
+    if (Pair[I].Src->getType() != Pair[I].Dst->getType())
+      return false;
 
     if (EnableMonotonicityCheck) {
       if (MonChecker.checkMonotonicity(Pair[I].Src, OutermostLoop).isUnknown())