forked from OSchip/llvm-project
31 lines
1.2 KiB
LLVM
31 lines
1.2 KiB
LLVM
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; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7
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; Verify that DAGCombiner does not crash when checking if it is
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; safe to fold the shuffles in function @sample_test according to rule
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; (shuffle (shuffle A, Undef, M0), Undef, M1) -> (shuffle A, Undef, M2)
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;
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; The DAGCombiner avoids folding shuffles if
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; the resulting shuffle dag node is not legal for the target.
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; That means, the shuffle must have legal type and legal mask.
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;
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; Before, the DAGCombiner forgot to check if the resulting shuffle
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; was legal. It instead just called method
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; 'X86TargetLowering::isShuffleMaskLegal'; however, that was not enough since
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; that method always expect to have a valid vector type in input.
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; As a consequence, compiling the function below would have caused a crash.
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define void @sample_test() {
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br i1 undef, label %5, label %1
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; <label>:1 ; preds = %0
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%2 = load <4 x i8>* undef
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%3 = shufflevector <4 x i8> %2, <4 x i8> undef, <4 x i32> <i32 2, i32 2, i32 0, i32 0>
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%4 = shufflevector <4 x i8> %3, <4 x i8> undef, <4 x i32> <i32 2, i32 3, i32 0, i32 1>
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store <4 x i8> %4, <4 x i8>* undef
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br label %5
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; <label>:5 ; preds = %1, %0
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ret void
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}
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