From: Max Kazantsev <mkazantsev@azul.com>
Date: Mon, 1 Mar 2021 06:22:42 +0000 (+0700)
Subject: [NFC] Detect IV increment expressed as uadd_with_overflow and usub_with_overflow
X-Git-Tag: llvmorg-14-init~13807
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9fac8496eae809c288096037d7a3f5a1a3d04c7a;p=platform%2Fupstream%2Fllvm.git

[NFC] Detect IV increment expressed as uadd_with_overflow and usub_with_overflow

Current callers do not call it with such argument, so this is NFC.
But for further changes, it can be very useful to detect such cases.
---

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 2c2f667b..d87d500 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1293,6 +1293,12 @@ getIVIncrement(const PHINode *PN, const LoopInfo *LI) {
     return std::make_pair(IVInc, ConstantExpr::getNeg(Step));
   if (match(IVInc, m_Add(m_Specific(PN), m_Constant(Step))))
     return std::make_pair(IVInc, Step);
+  if (match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::usub_with_overflow>(
+                       m_Specific(PN), m_Constant(Step)))))
+    return std::make_pair(IVInc, ConstantExpr::getNeg(Step));
+  if (match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::uadd_with_overflow>(
+                       m_Specific(PN), m_Constant(Step)))))
+    return std::make_pair(IVInc, Step);
   return None;
 }