[llvm] [TableGen][NFC] Add maybe_unused to MRI (PR #87044)

[Wang Pengcheng via llvm-commits]

https://github.com/wangpc-pp created https://github.com/llvm/llvm-project/pull/87044

This suppresses warning `unused variable 'MRI' [-Wunused-variable]`
for those fusions that don't need `MRI`.


>From 115a77a2daa31412f2ee2bc61992e51f9138d1cb Mon Sep 17 00:00:00 2001
From: Wang Pengcheng <wangpengcheng.pp at bytedance.com>
Date: Fri, 29 Mar 2024 16:16:09 +0800
Subject: [PATCH] [TableGen][NFC] Add maybe_unused to MRI

This suppresses warning `unused variable 'MRI' [-Wunused-variable]`
for those fusions that don't need `MRI`.
---
 llvm/utils/TableGen/MacroFusionPredicatorEmitter.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/utils/TableGen/MacroFusionPredicatorEmitter.cpp b/llvm/utils/TableGen/MacroFusionPredicatorEmitter.cpp
index e9e63fa8d0de8c..63b827a35177e3 100644
--- a/llvm/utils/TableGen/MacroFusionPredicatorEmitter.cpp
+++ b/llvm/utils/TableGen/MacroFusionPredicatorEmitter.cpp
@@ -108,7 +108,8 @@ void MacroFusionPredicatorEmitter::emitMacroFusionImpl(
     OS.indent(4) << "const TargetSubtargetInfo &STI,\n";
     OS.indent(4) << "const MachineInstr *FirstMI,\n";
     OS.indent(4) << "const MachineInstr &SecondMI) {\n";
-    OS.indent(2) << "auto &MRI = SecondMI.getMF()->getRegInfo();\n";
+    OS.indent(2)
+        << "[[maybe_unused]] auto &MRI = SecondMI.getMF()->getRegInfo();\n";
 
     emitPredicates(Predicates, IsCommutable, PE, OS);