[llvm] [IVDesc] Improve isConditionalRdxPattern (NFC) (PR #162818)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon created https://github.com/llvm/llvm-project/pull/162818

None

>From 57acf0fd19cf984a50bf6f7403ef97d672cd924c Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Fri, 10 Oct 2025 10:50:24 +0100
Subject: [PATCH] [IVDesc] Improve isConditionalRdxPattern (NFC)

---
 llvm/lib/Analysis/IVDescriptors.cpp | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index b8c540ce4b99d..9f8ac6e8e2e0b 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -849,17 +849,12 @@ RecurrenceDescriptor::isMinMaxPattern(Instruction *I, RecurKind Kind,
 /// %sum.2 = select %cmp, %add, %sum.1
 RecurrenceDescriptor::InstDesc
 RecurrenceDescriptor::isConditionalRdxPattern(Instruction *I) {
-  SelectInst *SI = dyn_cast<SelectInst>(I);
-  if (!SI)
-    return InstDesc(false, I);
-
-  CmpInst *CI = dyn_cast<CmpInst>(SI->getCondition());
+  Value *TrueVal, *FalseVal;
   // Only handle single use cases for now.
-  if (!CI || !CI->hasOneUse())
+  if (!match(I,
+             m_Select(m_OneUse(m_Cmp()), m_Value(TrueVal), m_Value(FalseVal))))
     return InstDesc(false, I);
 
-  Value *TrueVal = SI->getTrueValue();
-  Value *FalseVal = SI->getFalseValue();
   // Handle only when either of operands of select instruction is a PHI
   // node for now.
   if ((isa<PHINode>(TrueVal) && isa<PHINode>(FalseVal)) ||
@@ -886,7 +881,7 @@ RecurrenceDescriptor::isConditionalRdxPattern(Instruction *I) {
   if (!IPhi || IPhi != FalseVal)
     return InstDesc(false, I);
 
-  return InstDesc(true, SI);
+  return InstDesc(true, I);
 }
 
 RecurrenceDescriptor::InstDesc RecurrenceDescriptor::isRecurrenceInstr(