[llvm] [amdgpu] Add llvm.amdgcn.init.whole.wave intrinsic (PR #105822)

[Diana Picus via llvm-commits]

================
@@ -208,6 +208,20 @@ def int_amdgcn_init_exec_from_input : Intrinsic<[],
   [IntrConvergent, IntrHasSideEffects, IntrNoMem, IntrNoCallback,
    IntrNoFree, IntrWillReturn, ImmArg<ArgIndex<1>>]>;
 
+// Sets the function into whole-wave-mode and returns whether the lane was
+// active when entering the function. A branch depending on this return will
----------------
rovka wrote:

Sure, I don't think that's a hard requirement as much as an "I'm currently too lazy to think about/implement this for other calling conventions" requirement. I'm going to reword this.

https://github.com/llvm/llvm-project/pull/105822