Create a new channel as a copy of main.
Rename main to:
Delete main? This cannot be undone.
; RUN: opt < %s -passes=instcombine -S | grep zext ; PR1261. define i16 @test(i31 %zzz) { %A = sext i31 %zzz to i32 %B = add i32 %A, 16384 %C = lshr i32 %B, 15 %D = trunc i32 %C to i16 ret i16 %D }