[llvm] [LowerSwitch] Implement verifyAnalysis (PR #68294)

[Jay Foad via llvm-commits]

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@@ -569,8 +569,17 @@ class LowerSwitchLegacyPass : public FunctionPass {
     initializeLowerSwitchLegacyPassPass(*PassRegistry::getPassRegistry());
   }
 
+  // Remember the current function. Only used for verification.
+  Function *F;
+
   bool runOnFunction(Function &F) override;
 
+  void verifyAnalysis() const override {
+    for (auto &BB : *F)
+      assert(!isa<SwitchInst>(BB.getTerminator()) &&
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jayfoad wrote:

I'm just trying to follow existing patterns. They all seem to use `assert` so won't do anything in a normal Release build. I don't think most compilers warn about unused _public_ fields do they?

https://github.com/llvm/llvm-project/pull/68294