[llvm] [DAGCombine] Propagate truncate to operands (PR #98666)

[Matt Arsenault via llvm-commits]

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@@ -70,8 +70,9 @@ define i16 @add1_i16(ptr addrspace(1) nocapture %arg, ptr addrspace(1) nocapture
 ; GFX9-NEXT:    global_load_dword v0, v[0:1], off
 ; GFX9-NEXT:    v_bfe_u32 v1, v31, 10, 10
 ; GFX9-NEXT:    v_cmp_gt_u32_e32 vcc, v2, v1
+; GFX9-NEXT:    v_cndmask_b32_e64 v1, 0, 1, vcc
 ; GFX9-NEXT:    s_waitcnt vmcnt(0)
-; GFX9-NEXT:    v_addc_co_u32_e32 v0, vcc, 0, v0, vcc
+; GFX9-NEXT:    v_add_u16_e32 v0, v0, v1
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arsenm wrote:

This is worse 

https://github.com/llvm/llvm-project/pull/98666