[flang][Lower] fix warning (#148667)

tblah · web-flow · commit 3d6aac31fcb5 · 2025-07-14T17:59:50.000+01:00
GCC 9.3.0
```
.../flang/lib/Lower/Support/ReductionProcessor.cpp:137:1: error: control reaches end of non-void function [-Werror=return-type]
```
diff --git 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(

Original file line number	Diff line number	Diff line change
`@@ -134,6 +134,7 @@ ReductionProcessor::getReductionType(const fir::ReduceOperationEnum &redOp) {`
`134`	`134`	`case fir::ReduceOperationEnum::MIN:`
`135`	`135`	`return ReductionIdentifier::MIN;`
`136`	`136`	`}`
	`137`	`+ llvm_unreachable("Unhandled ReductionIdentifier case");`
`137`	`138`	`}`
`138`	`139`
`139`	`140`	`bool ReductionProcessor::supportedIntrinsicProcReduction(`