44 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			44 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 | FileCheck %s
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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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; CHECK-LABEL: sample_test:
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; CHECK:       # %bb.0:
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; CHECK-NEXT:    xorl %eax, %eax
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; CHECK-NEXT:    testb %al, %al
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; CHECK-NEXT:    jne .LBB0_2
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; CHECK-NEXT:  # %bb.1:
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; CHECK-NEXT:    movd {{.*#+}} xmm0 = mem[0],zero,zero,zero
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; CHECK-NEXT:    punpcklbw {{.*#+}} xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
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; CHECK-NEXT:    pshuflw {{.*#+}} xmm0 = xmm0[0,2,2,3,4,5,6,7]
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; CHECK-NEXT:    movd %xmm0, (%rax)
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; CHECK-NEXT:  .LBB0_2:
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; CHECK-NEXT:    retq
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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>, <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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