[PATCH] D119013: [ArgPromotion][AMDGPU] New MSSA-based function argument promotion pass with input/output argument support

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

This looks like a better version of AMDGPURewriteOutArguments which was never enabled. I wanted to replace that to use MSSA

Can you check if the testcases in llvm/test/CodeGen/AMDGPU/rewrite-out-arguments.ll are redundant and/or covered by the ones you add here?



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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:175
+  bool isMyLoad(Value *V) const {
+    return isa<LoadInst>(V) && isMyPtr(cast<LoadInst>(V)->getPointerOperand());
+  }
----------------
dyn_cast instead of isa and cast


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:178
+  bool isMyStore(Value *V) const {
+    return isa<StoreInst>(V) &&
+           isMyPtr(cast<StoreInst>(V)->getPointerOperand());
----------------
dyn_cast instead of isa and cast


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:184
+      return isMyPtr(LI->getPointerOperand());
+    else if (StoreInst *SI = dyn_cast<StoreInst>(V))
+      return isMyPtr(SI->getPointerOperand());
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No else after return


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:324-326
+             if (HasLoadOnEveryPath) dbgs() << "has a load on every path,";
+             else dbgs() << (Candidate.Preload ? "" : "not")
+                         << " all callers pass a valid dereferenceable ptr,");
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Weird formatting


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:813
+  for (BasicBlock &BB : *F)
+    if (auto *RetInst = dyn_cast_or_null<ReturnInst>(BB.getTerminator()))
+      RetValues[RetInst].push_back(getBBExitValue(&BB));
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The terminator can't be null


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:824
+#ifndef NDEBUG
+  MSSA.verifyMemorySSA();
+#endif
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I would assume this happens in the regular verifier with expensive checks?


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:856
+                    const ArgPromotionInfo *A2) const {
+      assert(!(A1->isClobberedBy(*A2) && A2->isClobberedBy(*A1)));
+      return A1->isClobberedBy(*A2);
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Demorgan this


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:912
+        Queue.push(&C);
+      // otherwise this is a circular dependency, other candidates will be
+      // removed by the condition [1]
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Capitalize


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:928
+  ReturnArgs.reserve(NumPromoted);
+  for (ArgPromotionInfo &C : Candidates)
+    if (C.isPromoted()) {
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Braces


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:954
+      unsigned I = 0;
+      if (!OldRetTy->isVoidTy())
+        RetValue = InsertValueInst::Create(
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Braces


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Comment at: llvm/lib/Transforms/IPO/MSSAArgPromotion.cpp:1385
+        assert(OldNode->getNumReferences() == 0);
+        delete CG.removeFunctionFromModule(OldNode);
+        SCC.ReplaceNode(OldNode, NewNode);
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It's weird to have raw deletes in llvm code, why do you need this here?


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Comment at: llvm/test/Transforms/ArgumentPromotion/inoutargs.ll:1103
+  ret i32 %Sum
+}
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I'd like to see some tests with more exotic memory operations (atomics, memcpy/memset, target memory intrinsics etc.).

I also don't see negative tests for some of the skipped conditions (e.g. musttail). Can you also add a test for invoke, and captured function address


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D119013/new/

https://reviews.llvm.org/D119013