[llvm] [AMDGPU] Remove duplicated/confusing helpers. NFCI (PR #142598)

[Matt Arsenault via llvm-commits]

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@@ -978,7 +978,9 @@ bool AMDGPUTargetMachine::isNoopAddrSpaceCast(unsigned SrcAS,
 
 unsigned AMDGPUTargetMachine::getAssumedAddrSpace(const Value *V) const {
   if (auto *Arg = dyn_cast<Argument>(V);
-      Arg && AMDGPU::isKernelCC(Arg->getParent()) && !Arg->hasByRefAttr())
+      Arg &&
+      AMDGPU::isModuleEntryFunctionCC(Arg->getParent()->getCallingConv()) &&
+      !Arg->hasByRefAttr())
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arsenm wrote:

This is a functionality change which ideally would be tested

https://github.com/llvm/llvm-project/pull/142598