From 8b894eaa42ea00344d66f6d4d4c4b0a449bedc98 Mon Sep 17 00:00:00 2001
From: Sychev Vadim <svd-main@outlook.com>
Date: Tue, 7 Jun 2022 20:28:41 +0300
Subject: [PATCH] Optimization for "~x + 1" to "-x" (#69003) (#69600)

---
 src/coreclr/jit/morph.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/coreclr/jit/morph.cpp b/src/coreclr/jit/morph.cpp
index f5d37cac855ad..c3f3d1762c07e 100644
--- a/src/coreclr/jit/morph.cpp
+++ b/src/coreclr/jit/morph.cpp
@@ -12895,6 +12895,16 @@ GenTree* Compiler::fgOptimizeAddition(GenTreeOp* add)
 
             return add;
         }
+
+        // Fold (~x + 1) to -x.
+        if (op1->OperIs(GT_NOT) && op2->IsIntegralConst(1))
+        {
+            op1->SetOper(GT_NEG);
+            op1->SetVNsFromNode(add);
+            DEBUG_DESTROY_NODE(op2);
+            DEBUG_DESTROY_NODE(add);
+            return op1;
+        }
     }
 
     return nullptr;