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Diffstat (limited to 'test/CodeGen/AArch64/arm64-AnInfiniteLoopInDAGCombine.ll')
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1 files changed, 23 insertions, 0 deletions
diff --git a/test/CodeGen/AArch64/arm64-AnInfiniteLoopInDAGCombine.ll b/test/CodeGen/AArch64/arm64-AnInfiniteLoopInDAGCombine.ll new file mode 100644 index 0000000..a73b707 --- /dev/null +++ b/test/CodeGen/AArch64/arm64-AnInfiniteLoopInDAGCombine.ll @@ -0,0 +1,23 @@ +; 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 +}
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