[llvm] [DXIL] Consume Metadata Analysis information in passes (PR #108034)

[Damyan Pepper via llvm-commits]

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@@ -247,9 +247,10 @@ class DXILPrepareModule : public ModulePass {
 
   DXILPrepareModule() : ModulePass(ID) {}
   void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesAll();
     AU.addPreserved<ShaderFlagsAnalysisWrapper>();
     AU.addPreserved<DXILResourceMDWrapper>();
-    AU.addPreserved<DXILMetadataAnalysisWrapperPass>();
+    AU.addRequired<DXILMetadataAnalysisWrapperPass>();
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damyanp wrote:

Likely an opportunity for me to learn something:

If we're using `setPreservesAll()` why do we need to explicitly call `addPreserved` on any other passes?

https://github.com/llvm/llvm-project/pull/108034