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|
; RUN: opt < %s -scev-aa -aa-eval -print-all-alias-modref-info \
; RUN: 2>&1 | FileCheck %s
; At the time of this writing, -basicaa misses the example of the form
; A[i+(j+1)] != A[i+j], which can arise from multi-dimensional array references,
; and the example of the form A[0] != A[i+1], where i+1 is known to be positive.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
; p[i] and p[i+1] don't alias.
; CHECK: Function: loop: 3 pointers, 0 call sites
; CHECK: NoAlias: double* %pi, double* %pi.next
define void @loop(double* nocapture %p, i64 %n) nounwind {
entry:
%j = icmp sgt i64 %n, 0
br i1 %j, label %bb, label %return
bb:
%i = phi i64 [ 0, %entry ], [ %i.next, %bb ]
%pi = getelementptr double* %p, i64 %i
%i.next = add i64 %i, 1
%pi.next = getelementptr double* %p, i64 %i.next
%x = load double* %pi
%y = load double* %pi.next
%z = fmul double %x, %y
store double %z, double* %pi
%exitcond = icmp eq i64 %i.next, %n
br i1 %exitcond, label %return, label %bb
return:
ret void
}
; Slightly more involved: p[j][i], p[j][i+1], and p[j+1][i] don't alias.
; CHECK: Function: nestedloop: 4 pointers, 0 call sites
; CHECK: NoAlias: double* %pi.j, double* %pi.next.j
; CHECK: NoAlias: double* %pi.j, double* %pi.j.next
; CHECK: NoAlias: double* %pi.j.next, double* %pi.next.j
define void @nestedloop(double* nocapture %p, i64 %m) nounwind {
entry:
%k = icmp sgt i64 %m, 0
br i1 %k, label %guard, label %return
guard:
%l = icmp sgt i64 91, 0
br i1 %l, label %outer.loop, label %return
outer.loop:
%j = phi i64 [ 0, %guard ], [ %j.next, %outer.latch ]
br label %bb
bb:
%i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
%i.next = add i64 %i, 1
%e = add i64 %i, %j
%pi.j = getelementptr double* %p, i64 %e
%f = add i64 %i.next, %j
%pi.next.j = getelementptr double* %p, i64 %f
%x = load double* %pi.j
%y = load double* %pi.next.j
%z = fmul double %x, %y
store double %z, double* %pi.j
%o = add i64 %j, 91
%g = add i64 %i, %o
%pi.j.next = getelementptr double* %p, i64 %g
%a = load double* %pi.j.next
%b = fmul double %x, %a
store double %b, double* %pi.j.next
%exitcond = icmp eq i64 %i.next, 91
br i1 %exitcond, label %outer.latch, label %bb
outer.latch:
%j.next = add i64 %j, 91
%h = icmp eq i64 %j.next, %m
br i1 %h, label %return, label %outer.loop
return:
ret void
}
; Even more involved: same as nestedloop, but with a variable extent.
; When n is 1, p[j+1][i] does alias p[j][i+1], and there's no way to
; prove whether n will be greater than 1, so that relation will always
; by MayAlias. The loop is guarded by a n > 0 test though, so
; p[j+1][i] and p[j][i] can theoretically be determined to be NoAlias,
; however the analysis currently doesn't do that.
; TODO: Make the analysis smarter and turn that MayAlias into a NoAlias.
; CHECK: Function: nestedloop_more: 4 pointers, 0 call sites
; CHECK: NoAlias: double* %pi.j, double* %pi.next.j
; CHECK: MayAlias: double* %pi.j, double* %pi.j.next
define void @nestedloop_more(double* nocapture %p, i64 %n, i64 %m) nounwind {
entry:
%k = icmp sgt i64 %m, 0
br i1 %k, label %guard, label %return
guard:
%l = icmp sgt i64 %n, 0
br i1 %l, label %outer.loop, label %return
outer.loop:
%j = phi i64 [ 0, %guard ], [ %j.next, %outer.latch ]
br label %bb
bb:
%i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
%i.next = add i64 %i, 1
%e = add i64 %i, %j
%pi.j = getelementptr double* %p, i64 %e
%f = add i64 %i.next, %j
%pi.next.j = getelementptr double* %p, i64 %f
%x = load double* %pi.j
%y = load double* %pi.next.j
%z = fmul double %x, %y
store double %z, double* %pi.j
%o = add i64 %j, %n
%g = add i64 %i, %o
%pi.j.next = getelementptr double* %p, i64 %g
%a = load double* %pi.j.next
%b = fmul double %x, %a
store double %b, double* %pi.j.next
%exitcond = icmp eq i64 %i.next, %n
br i1 %exitcond, label %outer.latch, label %bb
outer.latch:
%j.next = add i64 %j, %n
%h = icmp eq i64 %j.next, %m
br i1 %h, label %return, label %outer.loop
return:
ret void
}
; ScalarEvolution expands field offsets into constants, which allows it to
; do aggressive analysis. Contrast this with BasicAA, which works by
; recognizing GEP idioms.
%struct.A = type { %struct.B, i32, i32 }
%struct.B = type { double }
; CHECK: Function: foo: 7 pointers, 0 call sites
; CHECK: NoAlias: %struct.B* %B, i32* %Z
; CHECK: NoAlias: %struct.B* %B, %struct.B* %C
; CHECK: MustAlias: %struct.B* %C, i32* %Z
; CHECK: NoAlias: %struct.B* %B, i32* %X
; CHECK: MustAlias: i32* %X, i32* %Z
; CHECK: MustAlias: %struct.B* %C, i32* %Y
; CHECK: MustAlias: i32* %X, i32* %Y
define void @foo() {
entry:
%A = alloca %struct.A
%B = getelementptr %struct.A* %A, i32 0, i32 0
%Q = bitcast %struct.B* %B to %struct.A*
%Z = getelementptr %struct.A* %Q, i32 0, i32 1
%C = getelementptr %struct.B* %B, i32 1
%X = bitcast %struct.B* %C to i32*
%Y = getelementptr %struct.A* %A, i32 0, i32 1
ret void
}
; CHECK: Function: bar: 7 pointers, 0 call sites
; CHECK: NoAlias: %struct.B* %N, i32* %P
; CHECK: NoAlias: %struct.B* %N, %struct.B* %R
; CHECK: MustAlias: %struct.B* %R, i32* %P
; CHECK: NoAlias: %struct.B* %N, i32* %W
; CHECK: MustAlias: i32* %P, i32* %W
; CHECK: MustAlias: %struct.B* %R, i32* %V
; CHECK: MustAlias: i32* %V, i32* %W
define void @bar() {
%M = alloca %struct.A
%N = getelementptr %struct.A* %M, i32 0, i32 0
%O = bitcast %struct.B* %N to %struct.A*
%P = getelementptr %struct.A* %O, i32 0, i32 1
%R = getelementptr %struct.B* %N, i32 1
%W = bitcast %struct.B* %R to i32*
%V = getelementptr %struct.A* %M, i32 0, i32 1
ret void
}
; CHECK: Function: nonnegative: 2 pointers, 0 call sites
; CHECK: NoAlias: i64* %arrayidx, i64* %p
define void @nonnegative(i64* %p) nounwind {
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%i = phi i64 [ %inc, %for.body ], [ 0, %entry ] ; <i64> [#uses=2]
%inc = add nsw i64 %i, 1 ; <i64> [#uses=2]
%arrayidx = getelementptr inbounds i64* %p, i64 %inc
store i64 0, i64* %arrayidx
%tmp6 = load i64* %p ; <i64> [#uses=1]
%cmp = icmp slt i64 %inc, %tmp6 ; <i1> [#uses=1]
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.body, %entry
ret void
}
; CHECK: 14 no alias responses
; CHECK: 26 may alias responses
; CHECK: 18 must alias responses
|
