[llvm] [AMDGPU] Ensure divergence for v_alignbit (PR #129159)

[Matt Arsenault via llvm-commits]

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@@ -2499,9 +2499,9 @@ define amdgpu_kernel void @test_call_external_void_func_v3i16() #0 {
 ; CI-NEXT:    s_mov_b64 s[2:3], s[38:39]
 ; CI-NEXT:    s_mov_b32 s32, 0
 ; CI-NEXT:    s_waitcnt vmcnt(0)
-; CI-NEXT:    v_alignbit_b32 v1, v3, v2, 16
-; CI-NEXT:    v_mov_b32_e32 v0, v2
-; CI-NEXT:    v_mov_b32_e32 v2, v3
+; CI-NEXT:    v_lshr_b64 v[1:2], v[3:4], 16
+; CI-NEXT:    v_mov_b32_e32 v0, v3
+; CI-NEXT:    v_mov_b32_e32 v2, v4
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arsenm wrote:

Regression here. The uniformity is a flawed proxy for is SGPR 

https://github.com/llvm/llvm-project/pull/129159