[clang] [AMDGPU] const-fold imm operands of amdgcn_update_dpp intrinsic (PR #71139)

[Matt Arsenault via cfe-commits]

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@@ -17632,8 +17632,27 @@ Value *CodeGenFunction::EmitAMDGPUBuiltinExpr(unsigned BuiltinID,
   case AMDGPU::BI__builtin_amdgcn_mov_dpp:
   case AMDGPU::BI__builtin_amdgcn_update_dpp: {
     llvm::SmallVector<llvm::Value *, 6> Args;
-    for (unsigned I = 0; I != E->getNumArgs(); ++I)
-      Args.push_back(EmitScalarExpr(E->getArg(I)));
+    // Find out if any arguments are required to be integer constant
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arsenm wrote:

Can you factor the existing generic code into a helper function? This is mostly copy paste of the default builtin path 

https://github.com/llvm/llvm-project/pull/71139