[llvm] [NVPTX] add an optional early copy of byval arguments (PR #113384)

[Akshay Deodhar via llvm-commits]

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@@ -734,3 +739,21 @@ bool NVPTXLowerArgs::runOnFunction(Function &F) {
 }
 
 FunctionPass *llvm::createNVPTXLowerArgsPass() { return new NVPTXLowerArgs(); }
+
+static bool copyFunctionByValArgs(Function &F) {
+  LLVM_DEBUG(dbgs() << "Creating a copy of byval args of " << F.getName()
+                    << "\n");
+  bool Changed = false;
+  for (Argument &Arg : F.args())
+    if (Arg.getType()->isPointerTy() && Arg.hasByValAttr()) {
+      copyByValParam(F, Arg);
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akshayrdeodhar wrote:

to clarify: any readonly byvals which were not formerly lowered to allocas will get lowered to allocas, but SROA will convert loads from the allocas to loads from the byval pointer?

https://github.com/llvm/llvm-project/pull/113384