[llvm-branch-commits] [llvm] [DA] Remove ExtraGCD from GCD MIV (NFC) (PR #172004)

[Ryotaro Kasuga via llvm-branch-commits]

https://github.com/kasuga-fj updated https://github.com/llvm/llvm-project/pull/172004

>From d56f0e02a5614a02f8e770db0106e2b5bdd3baea Mon Sep 17 00:00:00 2001
From: Ryotaro Kasuga <kasuga.ryotaro at fujitsu.com>
Date: Fri, 12 Dec 2025 12:35:17 +0000
Subject: [PATCH] [DA] Remove ExtraGCD from GCD MIV (NFC)

---
 llvm/lib/Analysis/DependenceAnalysis.cpp | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 1abac06e232cc..837bd31a73952 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -2238,7 +2238,6 @@ bool DependenceInfo::gcdMIVtest(const SCEV *Src, const SCEV *Dst,
   }
   const SCEV *DstConst = Coefficients;
 
-  APInt ExtraGCD = APInt::getZero(BitWidth);
   const SCEV *Delta = minusSCEVNoSignedOverflow(DstConst, SrcConst, *SE);
   if (!Delta)
     return false;
@@ -2265,11 +2264,6 @@ bool DependenceInfo::gcdMIVtest(const SCEV *Src, const SCEV *Dst,
   // which is infeasible, so we can disallow the = direction for the i level.
   // Setting j = j' doesn't help matters, so we end up with a direction vector
   // of [<>, *]
-  //
-  // Given A[5*i + 10*j*M + 9*M*N] and A[15*i + 20*j*M - 21*N*M + 5],
-  // we need to remember that the constant part is 5 and the RunningGCD should
-  // be initialized to ExtraGCD = 30.
-  LLVM_DEBUG(dbgs() << "    ExtraGCD = " << ExtraGCD << '\n');
 
   bool Improved = false;
   Coefficients = Src;
@@ -2277,7 +2271,7 @@ bool DependenceInfo::gcdMIVtest(const SCEV *Src, const SCEV *Dst,
              dyn_cast<SCEVAddRecExpr>(Coefficients)) {
     Coefficients = AddRec->getStart();
     const Loop *CurLoop = AddRec->getLoop();
-    RunningGCD = ExtraGCD;
+    RunningGCD = 0;
     const SCEV *SrcCoeff = AddRec->getStepRecurrence(*SE);
     const SCEV *DstCoeff = SE->getMinusSCEV(SrcCoeff, SrcCoeff);