[llvm] [NewPM] Set diagnostic handler in `MachineModuleAnalysis` (PR #88229)

[Arthur Eubanks via llvm-commits]

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@@ -202,12 +211,17 @@ TEST_F(PassManagerTest, Basic) {
       TestMachineFunctionPass(Count, Counts)));
   MPM.addPass(TestMachineModulePass(Count, Counts));
   MFPM.addPass(TestMachineFunctionPass(Count, Counts));
+  MFPM.addPass(ReportWarningPass());
   MPM.addPass(createModuleToMachineFunctionPassAdaptor(std::move(MFPM)));
 
+  testing::internal::CaptureStderr();
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aeubanks wrote:

TIL `CaptureStderr`, this is good to know

I'd separate the `ReportWarningPass` run out to its own test that doesn't check `Counts`

https://github.com/llvm/llvm-project/pull/88229