[llvm] f2a6a97 - Fix MSVC "ignoring return value of function declared with 'nodiscard' attribute" warning. NFC.

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2023-05-23T11:40:33+01:00
New Revision: f2a6a9706925a64386a0833f9ff2a03017a90bb5

URL: https://github.com/llvm/llvm-project/commit/f2a6a9706925a64386a0833f9ff2a03017a90bb5
DIFF: https://github.com/llvm/llvm-project/commit/f2a6a9706925a64386a0833f9ff2a03017a90bb5.diff

LOG: Fix MSVC "ignoring return value of function declared with 'nodiscard' attribute" warning. NFC.

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/SimplifyCFG.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 0c481b4367c4..ddfc9d037ddc 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -6505,8 +6505,10 @@ static bool SwitchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
     // If the default is unreachable, all case values are s>= MinCaseVal. Then
     // we can try to attach nsw.
     bool MayWrap = true;
-    if (!DefaultIsReachable)
-      MaxCaseVal->getValue().ssub_ov(MinCaseVal->getValue(), MayWrap);
+    if (!DefaultIsReachable) {
+      APInt Res = MaxCaseVal->getValue().ssub_ov(MinCaseVal->getValue(), MayWrap);
+      (void)Res;
+    }
 
     TableIndex = Builder.CreateSub(SI->getCondition(), TableIndexOffset,
                                    "switch.tableidx", /*HasNUW =*/false,