[llvm] [Cygwin] Cygwin X86ISelDAGToDAG.cpp (PR #76284)

[徐持恒 Xu Chiheng via llvm-commits]

https://github.com/xu-chiheng updated https://github.com/llvm/llvm-project/pull/76284

>From 25497274dfddcaeddbd85ac5fe0da59dd6f256a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BE=90=E6=8C=81=E6=81=92=20Xu=20Chiheng?=
 <chiheng.xu at gmail.com>
Date: Thu, 4 Jan 2024 16:12:05 +0800
Subject: [PATCH] 1

---
 llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 77a997588c4fee..c478f1c3fd30c8 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2944,6 +2944,18 @@ bool X86DAGToDAGISel::selectMOV64Imm32(SDValue N, SDValue &Imm) {
     return false;
 
   Imm = N;
+  if (Subtarget->isTargetWindowsCygwin() && Subtarget->is64Bit()) {
+    if (N->getOpcode() != ISD::TargetGlobalAddress)
+      return TM.getCodeModel() == CodeModel::Small;
+
+    std::optional<ConstantRange> CR =
+        cast<GlobalAddressSDNode>(N)->getGlobal()->getAbsoluteSymbolRange();
+    if (!CR)
+      return TM.getCodeModel() == CodeModel::Small;
+
+    return CR->getUnsignedMax().ult(1ull << 32);
+  }
+
   // Small/medium code model can reference non-TargetGlobalAddress objects with
   // 32 bit constants.
   if (N->getOpcode() != ISD::TargetGlobalAddress) {