forked from OSchip/llvm-project
216 lines
6.4 KiB
LLVM
216 lines
6.4 KiB
LLVM
; RUN: opt < %s -scev-aa -aa-eval -print-all-alias-modref-info \
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; RUN: 2>&1 | FileCheck %s
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; At the time of this writing, -basicaa misses the example of the form
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; A[i+(j+1)] != A[i+j], which can arise from multi-dimensional array references,
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; and the example of the form A[0] != A[i+1], where i+1 is known to be positive.
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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"
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; p[i] and p[i+1] don't alias.
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; CHECK: Function: loop: 3 pointers, 0 call sites
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; CHECK: NoAlias: double* %pi, double* %pi.next
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define void @loop(double* nocapture %p, i64 %n) nounwind {
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entry:
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%j = icmp sgt i64 %n, 0
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br i1 %j, label %bb, label %return
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bb:
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%i = phi i64 [ 0, %entry ], [ %i.next, %bb ]
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%pi = getelementptr double* %p, i64 %i
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%i.next = add i64 %i, 1
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%pi.next = getelementptr double* %p, i64 %i.next
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%x = load double* %pi
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%y = load double* %pi.next
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%z = fmul double %x, %y
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store double %z, double* %pi
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%exitcond = icmp eq i64 %i.next, %n
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br i1 %exitcond, label %return, label %bb
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return:
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ret void
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}
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; Slightly more involved: p[j][i], p[j][i+1], and p[j+1][i] don't alias.
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; CHECK: Function: nestedloop: 4 pointers, 0 call sites
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; CHECK: NoAlias: double* %pi.j, double* %pi.next.j
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; CHECK: NoAlias: double* %pi.j, double* %pi.j.next
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; CHECK: NoAlias: double* %pi.j.next, double* %pi.next.j
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define void @nestedloop(double* nocapture %p, i64 %m) nounwind {
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entry:
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%k = icmp sgt i64 %m, 0
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br i1 %k, label %guard, label %return
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guard:
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%l = icmp sgt i64 91, 0
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br i1 %l, label %outer.loop, label %return
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outer.loop:
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%j = phi i64 [ 0, %guard ], [ %j.next, %outer.latch ]
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br label %bb
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bb:
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%i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
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%i.next = add i64 %i, 1
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%e = add i64 %i, %j
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%pi.j = getelementptr double* %p, i64 %e
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%f = add i64 %i.next, %j
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%pi.next.j = getelementptr double* %p, i64 %f
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%x = load double* %pi.j
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%y = load double* %pi.next.j
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%z = fmul double %x, %y
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store double %z, double* %pi.j
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%o = add i64 %j, 91
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%g = add i64 %i, %o
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%pi.j.next = getelementptr double* %p, i64 %g
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%a = load double* %pi.j.next
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%b = fmul double %x, %a
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store double %b, double* %pi.j.next
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%exitcond = icmp eq i64 %i.next, 91
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br i1 %exitcond, label %outer.latch, label %bb
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outer.latch:
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%j.next = add i64 %j, 91
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%h = icmp eq i64 %j.next, %m
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br i1 %h, label %return, label %outer.loop
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return:
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ret void
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}
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; Even more involved: same as nestedloop, but with a variable extent.
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; When n is 1, p[j+1][i] does alias p[j][i+1], and there's no way to
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; prove whether n will be greater than 1, so that relation will always
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; by MayAlias. The loop is guarded by a n > 0 test though, so
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; p[j+1][i] and p[j][i] can theoretically be determined to be NoAlias,
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; however the analysis currently doesn't do that.
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; TODO: Make the analysis smarter and turn that MayAlias into a NoAlias.
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; CHECK: Function: nestedloop_more: 4 pointers, 0 call sites
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; CHECK: NoAlias: double* %pi.j, double* %pi.next.j
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; CHECK: MayAlias: double* %pi.j, double* %pi.j.next
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define void @nestedloop_more(double* nocapture %p, i64 %n, i64 %m) nounwind {
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entry:
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%k = icmp sgt i64 %m, 0
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br i1 %k, label %guard, label %return
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guard:
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%l = icmp sgt i64 %n, 0
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br i1 %l, label %outer.loop, label %return
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outer.loop:
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%j = phi i64 [ 0, %guard ], [ %j.next, %outer.latch ]
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br label %bb
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bb:
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%i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
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%i.next = add i64 %i, 1
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%e = add i64 %i, %j
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%pi.j = getelementptr double* %p, i64 %e
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%f = add i64 %i.next, %j
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%pi.next.j = getelementptr double* %p, i64 %f
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%x = load double* %pi.j
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%y = load double* %pi.next.j
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%z = fmul double %x, %y
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store double %z, double* %pi.j
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%o = add i64 %j, %n
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%g = add i64 %i, %o
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%pi.j.next = getelementptr double* %p, i64 %g
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%a = load double* %pi.j.next
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%b = fmul double %x, %a
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store double %b, double* %pi.j.next
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%exitcond = icmp eq i64 %i.next, %n
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br i1 %exitcond, label %outer.latch, label %bb
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outer.latch:
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%j.next = add i64 %j, %n
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%h = icmp eq i64 %j.next, %m
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br i1 %h, label %return, label %outer.loop
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return:
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ret void
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}
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; ScalarEvolution expands field offsets into constants, which allows it to
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; do aggressive analysis. Contrast this with BasicAA, which works by
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; recognizing GEP idioms.
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%struct.A = type { %struct.B, i32, i32 }
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%struct.B = type { double }
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; CHECK: Function: foo: 7 pointers, 0 call sites
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; CHECK: NoAlias: %struct.B* %B, i32* %Z
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; CHECK: NoAlias: %struct.B* %B, %struct.B* %C
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; CHECK: MustAlias: %struct.B* %C, i32* %Z
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; CHECK: NoAlias: %struct.B* %B, i32* %X
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; CHECK: MustAlias: i32* %X, i32* %Z
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; CHECK: MustAlias: %struct.B* %C, i32* %Y
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; CHECK: MustAlias: i32* %X, i32* %Y
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define void @foo() {
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entry:
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%A = alloca %struct.A
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%B = getelementptr %struct.A* %A, i32 0, i32 0
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%Q = bitcast %struct.B* %B to %struct.A*
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%Z = getelementptr %struct.A* %Q, i32 0, i32 1
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%C = getelementptr %struct.B* %B, i32 1
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%X = bitcast %struct.B* %C to i32*
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%Y = getelementptr %struct.A* %A, i32 0, i32 1
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ret void
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}
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; CHECK: Function: bar: 7 pointers, 0 call sites
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; CHECK: NoAlias: %struct.B* %N, i32* %P
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; CHECK: NoAlias: %struct.B* %N, %struct.B* %R
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; CHECK: MustAlias: %struct.B* %R, i32* %P
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; CHECK: NoAlias: %struct.B* %N, i32* %W
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; CHECK: MustAlias: i32* %P, i32* %W
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; CHECK: MustAlias: %struct.B* %R, i32* %V
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; CHECK: MustAlias: i32* %V, i32* %W
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define void @bar() {
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%M = alloca %struct.A
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%N = getelementptr %struct.A* %M, i32 0, i32 0
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%O = bitcast %struct.B* %N to %struct.A*
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%P = getelementptr %struct.A* %O, i32 0, i32 1
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%R = getelementptr %struct.B* %N, i32 1
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%W = bitcast %struct.B* %R to i32*
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%V = getelementptr %struct.A* %M, i32 0, i32 1
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ret void
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}
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; CHECK: Function: nonnegative: 2 pointers, 0 call sites
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; CHECK: NoAlias: i64* %arrayidx, i64* %p
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define void @nonnegative(i64* %p) nounwind {
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entry:
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br label %for.body
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for.body: ; preds = %entry, %for.body
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%i = phi i64 [ %inc, %for.body ], [ 0, %entry ] ; <i64> [#uses=2]
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%inc = add nsw i64 %i, 1 ; <i64> [#uses=2]
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%arrayidx = getelementptr inbounds i64* %p, i64 %inc
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store i64 0, i64* %arrayidx
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%tmp6 = load i64* %p ; <i64> [#uses=1]
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%cmp = icmp slt i64 %inc, %tmp6 ; <i1> [#uses=1]
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br i1 %cmp, label %for.body, label %for.end
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for.end: ; preds = %for.body, %entry
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ret void
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}
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; CHECK: 14 no alias responses
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; CHECK: 26 may alias responses
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; CHECK: 18 must alias responses
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