Mercurial > hg > CbC > CbC_llvm
view test/CodeGen/AArch64/arm64-AnInfiniteLoopInDAGCombine.ll @ 100:7d135dc70f03 LLVM 3.9
LLVM 3.9
author | Miyagi Mitsuki <e135756@ie.u-ryukyu.ac.jp> |
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date | Tue, 26 Jan 2016 22:53:40 +0900 |
parents | 54457678186b |
children | 1172e4bd9c6f |
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; RUN: llc < %s -march=arm64 ; This test case tests an infinite loop bug in DAG combiner. ; It just tries to do the following replacing endlessly: ; (1) Replacing.3 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4] ; With: 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4] ; ; (2) Replacing.2 0x2c4d128: v4i32 = sign_extend 0x2c4cd08 [ORD=4] ; With: 0x2c509f0: v4i32 = any_extend 0x2c4cd08 [ORD=4] ; As we think the (2) optimization from SIGN_EXTEND to ANY_EXTEND is ; an optimization to replace unused bits with undefined bits, we remove ; the (1) optimization (It doesn't make sense to replace undefined bits ; with signed bits). define <4 x i32> @infiniteLoop(<4 x i32> %in0, <4 x i16> %in1) { entry: %cmp.i = icmp sge <4 x i16> %in1, <i16 32767, i16 32767, i16 -1, i16 -32768> %sext.i = sext <4 x i1> %cmp.i to <4 x i32> %mul.i = mul <4 x i32> %in0, %sext.i %sext = shl <4 x i32> %mul.i, <i32 16, i32 16, i32 16, i32 16> %vmovl.i.i = ashr <4 x i32> %sext, <i32 16, i32 16, i32 16, i32 16> ret <4 x i32> %vmovl.i.i }