[llvm] [AMDGPU] Lazily emit waitcnts on function entry (PR #73122)

[Diana Picus via llvm-commits]

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@@ -44,7 +46,6 @@ entry:
 define ptr addrspace(1) @tail_call_assert_align() {
 ; CHECK-LABEL: tail_call_assert_align:
 ; CHECK:       ; %bb.0: ; %entry
-; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
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rovka wrote:

Why do these drop completely here, but in the next test (`br-constant-invalid-sgpr-copy.ll`) they just move to the end of the function? Is it because this function returns something, so it's the caller's job to wait before reading the results? 

https://github.com/llvm/llvm-project/pull/73122