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1; RUN: llc < %s -mtriple=arm64-eabi2 3; This test case tests an infinite loop bug in DAG combiner.4; It just tries to do the following replacing endlessly:5; (1) Replacing.3 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4]6; With: 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4]7;8; (2) Replacing.2 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4]9; With: 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4]10; As we think the (2) optimization from SIGN_EXTEND to ANY_EXTEND is11; an optimization to replace unused bits with undefined bits, we remove12; the (1) optimization (It doesn't make sense to replace undefined bits13; with signed bits).14 15define <4 x i32> @infiniteLoop(<4 x i32> %in0, <4 x i16> %in1) {16entry:17 %cmp.i = icmp sge <4 x i16> %in1, <i16 32767, i16 32767, i16 -1, i16 -32768>18 %sext.i = sext <4 x i1> %cmp.i to <4 x i32>19 %mul.i = mul <4 x i32> %in0, %sext.i20 %sext = shl <4 x i32> %mul.i, <i32 16, i32 16, i32 16, i32 16>21 %vmovl.i.i = ashr <4 x i32> %sext, <i32 16, i32 16, i32 16, i32 16>22 ret <4 x i32> %vmovl.i.i23}24