53 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			53 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt -basicaa -loop-accesses -analyze < %s | FileCheck %s
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; RUN: opt -passes='require<aa>,require<scalar-evolution>,require<aa>,loop(print-access-info)' -aa-pipeline='basic-aa' -disable-output < %s  2>&1 | FileCheck %s
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; If the arrays don't alias this loop is safe with no memchecks:
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;   for (i = 0; i < n; i++)
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;    A[i] = A[i+1] * B[i] * C[i];
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.10.0"
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; Check the loop-carried forward anti-dep between the load of A[i+1] and the
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; store of A[i];
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; CHECK: Memory dependences are safe{{$}}
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; CHECK-NEXT: Dependences:
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; CHECK-NEXT:   Forward:
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; CHECK-NEXT:     %loadA_plus_2 = load i16, i16* %arrayidxA_plus_2, align 2 ->
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; CHECK-NEXT:     store i16 %mul1, i16* %arrayidxA, align 2
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define void @f(i16* noalias %a,
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               i16* noalias %b,
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               i16* noalias %c) {
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entry:
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  br label %for.body
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for.body:                                         ; preds = %for.body, %entry
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  %ind = phi i64 [ 0, %entry ], [ %add, %for.body ]
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  %add = add nuw nsw i64 %ind, 1
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  %arrayidxA_plus_2 = getelementptr inbounds i16, i16* %a, i64 %add
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  %loadA_plus_2 = load i16, i16* %arrayidxA_plus_2, align 2
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  %arrayidxB = getelementptr inbounds i16, i16* %b, i64 %ind
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  %loadB = load i16, i16* %arrayidxB, align 2
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  %arrayidxC = getelementptr inbounds i16, i16* %c, i64 %ind
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  %loadC = load i16, i16* %arrayidxC, align 2
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  %mul = mul i16 %loadB, %loadA_plus_2
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  %mul1 = mul i16 %mul, %loadC
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  %arrayidxA = getelementptr inbounds i16, i16* %a, i64 %ind
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  store i16 %mul1, i16* %arrayidxA, align 2
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  %exitcond = icmp eq i64 %add, 20
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  br i1 %exitcond, label %for.end, label %for.body
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for.end:                                          ; preds = %for.body
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  ret void
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}
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