223 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			223 lines
		
	
	
		
			6.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt < %s -loop-vectorize -force-vector-width=2 -force-vector-unroll=1 -S | FileCheck %s
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; RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-unroll=1 -S | FileCheck %s -check-prefix=WIDTH
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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; Vectorization with dependence checks.
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; No plausible dependence - can be vectorized.
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;  for (i = 0; i < 1024; ++i)
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;    A[i] = A[i + 1] + 1;
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; CHECK: f1_vec
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; CHECK: <2 x i32>
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define void @f1_vec(i32* %A) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i32 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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  %indvars.iv.next = add i32 %indvars.iv, 1
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  %arrayidx = getelementptr inbounds i32* %A, i32 %indvars.iv.next
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  %0 = load i32* %arrayidx, align 4
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  %add1 = add nsw i32 %0, 1
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  %arrayidx3 = getelementptr inbounds i32* %A, i32 %indvars.iv
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  store i32 %add1, i32* %arrayidx3, align 4
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  %exitcond = icmp ne i32 %indvars.iv.next, 1024
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret void
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}
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; Plausible dependence of distance 1 - can't be vectorized.
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;  for (i = 0; i < 1024; ++i)
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;    A[i+1] = A[i] + 1;
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; CHECK: f2_novec
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; CHECK-NOT: <2 x i32>
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define void @f2_novec(i32* %A) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i32 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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  %arrayidx = getelementptr inbounds i32* %A, i32 %indvars.iv
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  %0 = load i32* %arrayidx, align 4
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  %add = add nsw i32 %0, 1
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  %indvars.iv.next = add i32 %indvars.iv, 1
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  %arrayidx3 = getelementptr inbounds i32* %A, i32 %indvars.iv.next
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  store i32 %add, i32* %arrayidx3, align 4
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  %exitcond = icmp ne i32 %indvars.iv.next, 1024
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret void
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}
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; Plausible dependence of distance 2 - can be vectorized with a width of 2.
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;  for (i = 0; i < 1024; ++i)
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;    A[i+2] = A[i] + 1;
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; CHECK: f3_vec_len
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; CHECK: <2 x i32>
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; WIDTH: f3_vec_len
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; WIDTH-NOT: <4 x i32>
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define void @f3_vec_len(i32* %A) {
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entry:
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  br label %for.body
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for.body:
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  %i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
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  %idxprom = sext i32 %i.01 to i64
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  %arrayidx = getelementptr inbounds i32* %A, i64 %idxprom
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  %0 = load i32* %arrayidx, align 4
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  %add = add nsw i32 %0, 1
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  %add1 = add nsw i32 %i.01, 2
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  %idxprom2 = sext i32 %add1 to i64
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  %arrayidx3 = getelementptr inbounds i32* %A, i64 %idxprom2
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  store i32 %add, i32* %arrayidx3, align 4
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  %inc = add nsw i32 %i.01, 1
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  %cmp = icmp slt i32 %inc, 1024
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  br i1 %cmp, label %for.body, label %for.end
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for.end:
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  ret void
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}
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; Plausible dependence of distance 1 - cannot be vectorized (without reordering
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; accesses).
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;   for (i = 0; i < 1024; ++i) {
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;     B[i] = A[i];
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;     A[i] = B[i + 1];
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;   }
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; CHECK: f5
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; CHECK-NOT: <2 x i32>
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define void @f5(i32*  %A, i32* %B) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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  %arrayidx = getelementptr inbounds i32* %A, i64 %indvars.iv
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  %0 = load i32* %arrayidx, align 4
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  %arrayidx2 = getelementptr inbounds i32* %B, i64 %indvars.iv
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  store i32 %0, i32* %arrayidx2, align 4
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  %indvars.iv.next = add nsw i64 %indvars.iv, 1
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  %arrayidx4 = getelementptr inbounds i32* %B, i64 %indvars.iv.next
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  %1 = load i32* %arrayidx4, align 4
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  store i32 %1, i32* %arrayidx, align 4
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  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
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  %exitcond = icmp ne i32 %lftr.wideiv, 1024
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret void
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}
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; Dependence through a phi node - must not vectorize.
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;   for (i = 0; i < 1024; ++i) {
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;     a[i+1] = tmp;
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;     tmp = a[i];
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;   }
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; CHECK: f6
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; CHECK-NOT: <2 x i32>
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define i32 @f6(i32* %a, i32 %tmp) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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  %tmp.addr.08 = phi i32 [ %tmp, %entry ], [ %0, %for.body ]
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  %indvars.iv.next = add nsw i64 %indvars.iv, 1
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  %arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv.next
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  store i32 %tmp.addr.08, i32* %arrayidx, align 4
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  %arrayidx3 = getelementptr inbounds i32* %a, i64 %indvars.iv
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  %0 = load i32* %arrayidx3, align 4
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  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
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  %exitcond = icmp ne i32 %lftr.wideiv, 1024
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret i32 undef
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}
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; Don't vectorize true loop carried dependencies that are not a multiple of the
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; vector width.
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; Example:
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;   for (int i = ...; ++i) {
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;     a[i] = a[i-3] + ...;
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; It is a bad idea to vectorize this loop because store-load forwarding will not
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; happen.
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;
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; CHECK: @nostoreloadforward
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; CHECK-NOT: <2 x i32>
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define void @nostoreloadforward(i32* %A) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i64 [ 16, %entry ], [ %indvars.iv.next, %for.body ]
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  %0 = add nsw i64 %indvars.iv, -3
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  %arrayidx = getelementptr inbounds i32* %A, i64 %0
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  %1 = load i32* %arrayidx, align 4
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  %2 = add nsw i64 %indvars.iv, 4
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  %arrayidx2 = getelementptr inbounds i32* %A, i64 %2
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  %3 = load i32* %arrayidx2, align 4
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  %add3 = add nsw i32 %3, %1
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  %arrayidx5 = getelementptr inbounds i32* %A, i64 %indvars.iv
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  store i32 %add3, i32* %arrayidx5, align 4
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  %indvars.iv.next = add i64 %indvars.iv, 1
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  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
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  %exitcond = icmp ne i32 %lftr.wideiv, 128
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret void
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}
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; Example:
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;   for (int i = ...; ++i) {
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;     a[i] = b[i];
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;     c[i] = a[i-3] + ...;
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; It is a bad idea to vectorize this loop because store-load forwarding will not
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; happen.
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;
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; CHECK: @nostoreloadforward2
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; CHECK-NOT: <2 x i32>
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define void @nostoreloadforward2(i32* noalias %A, i32* noalias %B, i32* noalias %C) {
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entry:
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  br label %for.body
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for.body:
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  %indvars.iv = phi i64 [ 16, %entry ], [ %indvars.iv.next, %for.body ]
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  %arrayidx = getelementptr inbounds i32* %B, i64 %indvars.iv
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  %0 = load i32* %arrayidx, align 4
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  %arrayidx2 = getelementptr inbounds i32* %A, i64 %indvars.iv
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  store i32 %0, i32* %arrayidx2, align 4
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  %1 = add nsw i64 %indvars.iv, -3
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  %arrayidx4 = getelementptr inbounds i32* %A, i64 %1
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  %2 = load i32* %arrayidx4, align 4
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  %arrayidx6 = getelementptr inbounds i32* %C, i64 %indvars.iv
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  store i32 %2, i32* %arrayidx6, align 4
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  %indvars.iv.next = add i64 %indvars.iv, 1
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  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
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  %exitcond = icmp ne i32 %lftr.wideiv, 128
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  br i1 %exitcond, label %for.body, label %for.end
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for.end:
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  ret void
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}
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