From 7faad5c90033c56a32b07eac527a456d60ed9a70 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 8 Mar 2021 17:18:01 +0100
Subject: [ConstantFold] Handle icmp of global and null consistently

Return UGT rather than NE for icmp @g, null, which is slightly
stronger. This is consistent with what we do for more complex
folds. It is somewhat silly that @g ugt null does not get folded
while (gep @g) ugt null does.
---
 llvm/lib/IR/ConstantFold.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'llvm/lib/IR/ConstantFold.cpp')

diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp
index 2e0ea4c..3701769 100644
--- a/llvm/lib/IR/ConstantFold.cpp
+++ b/llvm/lib/IR/ConstantFold.cpp
@@ -1764,7 +1764,7 @@ static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
       if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV) &&
           !NullPointerIsDefined(nullptr /* F */,
                                 GV->getType()->getAddressSpace()))
-        return ICmpInst::ICMP_NE;
+        return ICmpInst::ICMP_UGT;
     }
   } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
     if (isa<ConstantExpr>(V2)) {  // Swap as necessary.
-- 
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