[PATCH] D105590: [amdgpu] Remove the GlobalDCE pass prior to the internalization pass.

[Michael Liao via Phabricator via llvm-commits]

hliao created this revision.
hliao added reviewers: yaxunl, tra, rjmccall, rampitec.
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- In D98783 <https://reviews.llvm.org/D98783>, an extra GlobalDCE pass is inserted before the internalization pass to ensure a global variable without users could be internalized even if there are dead users. Instead of inserting a dedicated optimization pass, the dead user checking, i.e. 'use_empty()', should be preceeded with constant dead user removal to ensure an accurate result.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105590

Files:
  llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp


Index: llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -431,6 +431,7 @@
   if (const Function *F = dyn_cast<Function>(&GV))
     return F->isDeclaration() || AMDGPU::isEntryFunctionCC(F->getCallingConv());
 
+  GV.removeDeadConstantUsers();
   return !GV.use_empty();
 }
 
@@ -595,9 +596,6 @@
         PM.addPass(AMDGPUPrintfRuntimeBindingPass());
 
         if (InternalizeSymbols) {
-          // Global variables may have dead uses which need to be removed.
-          // Otherwise these useless global variables will not get internalized.
-          PM.addPass(GlobalDCEPass());
           PM.addPass(InternalizePass(mustPreserveGV));
         }
         PM.addPass(AMDGPUPropagateAttributesLatePass(*this));


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