[flang-commits] [flang] [flang][Lower] fix warning (PR #148667)

[Tom Eccles via flang-commits]

https://github.com/tblah created https://github.com/llvm/llvm-project/pull/148667

GCC 9.3.0
```
.../flang/lib/Lower/Support/ReductionProcessor.cpp:137:1: error: control reaches end of non-void function [-Werror=return-type]
```

>From d7efe3a8d91de159f1ded451d63fec5d7e466991 Mon Sep 17 00:00:00 2001
From: Tom Eccles <tom.eccles at arm.com>
Date: Mon, 14 Jul 2025 16:44:03 +0000
Subject: [PATCH] [flang][Lower] fix warning

GCC 9.3.0
```
.../flang/lib/Lower/Support/ReductionProcessor.cpp:137:1: error: control reaches end of non-void function [-Werror=return-type]
```
---
 flang/lib/Lower/Support/ReductionProcessor.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/flang/lib/Lower/Support/ReductionProcessor.cpp b/flang/lib/Lower/Support/ReductionProcessor.cpp
index 77cb15a2a77ca..c0be1e229f825 100644
--- a/flang/lib/Lower/Support/ReductionProcessor.cpp
+++ b/flang/lib/Lower/Support/ReductionProcessor.cpp
@@ -134,6 +134,7 @@ ReductionProcessor::getReductionType(const fir::ReduceOperationEnum &redOp) {
   case fir::ReduceOperationEnum::MIN:
     return ReductionIdentifier::MIN;
   }
+  llvm_unreachable("Unhandled ReductionIdentifier case");
 }
 
 bool ReductionProcessor::supportedIntrinsicProcReduction(