[llvm] [IVDescriptors][NFC] Refactor getReductionOpChain to remove the dependency of non-arithmetic reductions on getOpcode. (PR #118777)

[Mel Chen via llvm-commits]

https://github.com/Mel-Chen updated https://github.com/llvm/llvm-project/pull/118777

>From c0578edbb74b4e8c474fa4ad41455e6d0d9c7535 Mon Sep 17 00:00:00 2001
From: Mel Chen <mel.chen at sifive.com>
Date: Thu, 5 Dec 2024 01:34:22 -0800
Subject: [PATCH 1/2] [IVDescriptors][NFC] Refactor getReductionOpChain to
 remove the dependency of non-arithmetic reductions on getOpcode.

---
 llvm/include/llvm/Analysis/IVDescriptors.h | 3 +++
 llvm/lib/Analysis/IVDescriptors.cpp        | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index 42bccdc028461..7c8654eb50517 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -230,6 +230,9 @@ class RecurrenceDescriptor {
   /// Returns true if the recurrence kind is a floating point kind.
   static bool isFloatingPointRecurrenceKind(RecurKind Kind);
 
+  /// Returns true if the recurrence kind is arithmetic.
+  static bool isArithmeticRecurrenceKind(RecurKind Kind);
+
   /// Returns true if the recurrence kind is an integer min/max kind.
   static bool isIntMinMaxRecurrenceKind(RecurKind Kind) {
     return Kind == RecurKind::UMin || Kind == RecurKind::UMax ||
diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 45b5b2979a562..62fe9b3e66c2a 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -62,6 +62,11 @@ bool RecurrenceDescriptor::isFloatingPointRecurrenceKind(RecurKind Kind) {
   return (Kind != RecurKind::None) && !isIntegerRecurrenceKind(Kind);
 }
 
+bool RecurrenceDescriptor::isArithmeticRecurrenceKind(RecurKind Kind) {
+  return (Kind != RecurKind::None) && !isMinMaxRecurrenceKind(Kind) &&
+         !isAnyOfRecurrenceKind(Kind);
+}
+
 /// Determines if Phi may have been type-promoted. If Phi has a single user
 /// that ANDs the Phi with a type mask, return the user. RT is updated to
 /// account for the narrower bit width represented by the mask, and the AND
@@ -1166,7 +1171,6 @@ unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind) {
 SmallVector<Instruction *, 4>
 RecurrenceDescriptor::getReductionOpChain(PHINode *Phi, Loop *L) const {
   SmallVector<Instruction *, 4> ReductionOperations;
-  unsigned RedOp = getOpcode();
   const bool IsMinMax = isMinMaxRecurrenceKind(Kind);
 
   // Search down from the Phi to the LoopExitInstr, looking for instructions
@@ -1214,7 +1218,7 @@ RecurrenceDescriptor::getReductionOpChain(PHINode *Phi, Loop *L) const {
     if (isFMulAddIntrinsic(Cur))
       return true;
 
-    return Cur->getOpcode() == RedOp;
+    return Cur->getOpcode() == getOpcode();
   };
 
   // Attempt to look through Phis which are part of the reduction chain

>From 367cfd1893327f24801cc515b567409cde0acbc8 Mon Sep 17 00:00:00 2001
From: Mel Chen <mel.chen at sifive.com>
Date: Mon, 24 Mar 2025 02:46:10 -0700
Subject: [PATCH 2/2] Rebase, and remove isArithmeticRecurrenceKind

---
 llvm/include/llvm/Analysis/IVDescriptors.h | 3 ---
 llvm/lib/Analysis/IVDescriptors.cpp        | 5 -----
 2 files changed, 8 deletions(-)

diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index 7c8654eb50517..42bccdc028461 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -230,9 +230,6 @@ class RecurrenceDescriptor {
   /// Returns true if the recurrence kind is a floating point kind.
   static bool isFloatingPointRecurrenceKind(RecurKind Kind);
 
-  /// Returns true if the recurrence kind is arithmetic.
-  static bool isArithmeticRecurrenceKind(RecurKind Kind);
-
   /// Returns true if the recurrence kind is an integer min/max kind.
   static bool isIntMinMaxRecurrenceKind(RecurKind Kind) {
     return Kind == RecurKind::UMin || Kind == RecurKind::UMax ||
diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 62fe9b3e66c2a..7ea686fc5a0c4 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -62,11 +62,6 @@ bool RecurrenceDescriptor::isFloatingPointRecurrenceKind(RecurKind Kind) {
   return (Kind != RecurKind::None) && !isIntegerRecurrenceKind(Kind);
 }
 
-bool RecurrenceDescriptor::isArithmeticRecurrenceKind(RecurKind Kind) {
-  return (Kind != RecurKind::None) && !isMinMaxRecurrenceKind(Kind) &&
-         !isAnyOfRecurrenceKind(Kind);
-}
-
 /// Determines if Phi may have been type-promoted. If Phi has a single user
 /// that ANDs the Phi with a type mask, return the user. RT is updated to
 /// account for the narrower bit width represented by the mask, and the AND