; RUN: opt -disable-output < %s -aa-pipeline=scev-aa -passes=aa-eval -print-all-alias-modref-info \
; RUN: 2>&1 | FileCheck %s
; At the time of this writing, -basic-aa 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-LABEL: Function: loop
; 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, double* %p, i64 %i
%i.next = add i64 %i, 1
%pi.next = getelementptr double, double* %p, i64 %i.next
%x = load double, double* %pi
%y = load double, 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-LABEL: Function: nestedloop
; 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, double* %p, i64 %e
%f = add i64 %i.next, %j
%pi.next.j = getelementptr double, double* %p, i64 %f
%x = load double, double* %pi.j
%y = load double, 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, double* %p, i64 %g
%a = load double, 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-LABEL: Function: nestedloop_more
; 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, double* %p, i64 %e
%f = add i64 %i.next, %j
%pi.next.j = getelementptr double, double* %p, i64 %f
%x = load double, double* %pi.j
%y = load double, 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, double* %p, i64 %g
%a = load double, 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-LABEL: Function: foo
; CHECK-DAG: NoAlias: %struct.B* %B, i32* %Z
; CHECK-DAG: NoAlias: %struct.B* %B, %struct.B* %C
; CHECK-DAG: MustAlias: %struct.B* %C, i32* %Z
; CHECK-DAG: NoAlias: %struct.B* %B, i32* %X
; CHECK-DAG: MustAlias: i32* %X, i32* %Z
; CHECK-DAG: MustAlias: %struct.B* %C, i32* %Y
; CHECK-DAG: MustAlias: i32* %X, i32* %Y
define void @foo() {
entry:
%A = alloca %struct.A
%B = getelementptr %struct.A, %struct.A* %A, i32 0, i32 0
%Q = bitcast %struct.B* %B to %struct.A*
%Z = getelementptr %struct.A, %struct.A* %Q, i32 0, i32 1
%C = getelementptr %struct.B, %struct.B* %B, i32 1
%X = bitcast %struct.B* %C to i32*
%Y = getelementptr %struct.A, %struct.A* %A, i32 0, i32 1
load %struct.B, %struct.B* %B
load %struct.B, %struct.B* %C
load i32, i32* %X
load i32, i32* %Y
load i32, i32* %Z
ret void
}
; CHECK-LABEL: Function: bar
; CHECK-DAG: NoAlias: %struct.B* %N, i32* %P
; CHECK-DAG: NoAlias: %struct.B* %N, %struct.B* %R
; CHECK-DAG: MustAlias: i32* %P, %struct.B* %R
; CHECK-DAG: NoAlias: %struct.B* %N, i32* %W
; CHECK-DAG: MustAlias: i32* %P, i32* %W
; CHECK-DAG: MustAlias: %struct.B* %R, i32* %V
; CHECK-DAG: MustAlias: i32* %V, i32* %W
define void @bar() {
%M = alloca %struct.A
%N = getelementptr %struct.A, %struct.A* %M, i32 0, i32 0
%O = bitcast %struct.B* %N to %struct.A*
%P = getelementptr %struct.A, %struct.A* %O, i32 0, i32 1
%R = getelementptr %struct.B, %struct.B* %N, i32 1
%W = bitcast %struct.B* %R to i32*
%V = getelementptr %struct.A, %struct.A* %M, i32 0, i32 1
load %struct.B, %struct.B* %N
load %struct.B, %struct.B* %R
load i32, i32* %P
load i32, i32* %V
load i32, i32* %W
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, i64* %p, i64 %inc
store i64 0, i64* %arrayidx
%tmp6 = load i64, 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-LABEL: Function: test_no_dom: 3 pointers, 0 call sites
; CHECK: MayAlias: double* %addr1, double* %data
; CHECK: NoAlias: double* %addr2, double* %data
; CHECK: MayAlias: double* %addr1, double* %addr2
; In this case, checking %addr1 and %add2 involves two addrecs in two
; different loops where neither dominates the other. This used to crash
; because we expected the arguments to an AddExpr to have a strict
; dominance order.
define void @test_no_dom(double* %data) {
entry:
load double, double* %data
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.latch ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br i1 undef, label %subloop1, label %subloop2
subloop1:
%iv1 = phi i32 [0, %for.body], [%iv1.next, %subloop1]
%iv1.next = add i32 %iv1, 1
%addr1 = getelementptr double, double* %data, i32 %iv1
store double 0.0, double* %addr1
%cmp1 = icmp slt i32 %iv1, 200
br i1 %cmp1, label %subloop1, label %for.latch
subloop2:
%iv2 = phi i32 [400, %for.body], [%iv2.next, %subloop2]
%iv2.next = add i32 %iv2, 1
%addr2 = getelementptr double, double* %data, i32 %iv2
store double 0.0, double* %addr2
%cmp2 = icmp slt i32 %iv2, 600
br i1 %cmp2, label %subloop2, label %for.latch
for.latch:
br label %for.body
for.end:
ret void
}
declare double* @get_addr(i32 %i)
; CHECK-LABEL: Function: test_no_dom2: 3 pointers, 2 call sites
; CHECK: MayAlias: double* %addr1, double* %data
; CHECK: MayAlias: double* %addr2, double* %data
; CHECK: MayAlias: double* %addr1, double* %addr2
; In this case, checking %addr1 and %add2 involves two addrecs in two
; different loops where neither dominates the other. This is analogous
; to test_no_dom, but involves SCEVUnknown as opposed to SCEVAddRecExpr.
define void @test_no_dom2(double* %data) {
entry:
load double, double* %data
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.latch ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br i1 undef, label %subloop1, label %subloop2
subloop1:
%iv1 = phi i32 [0, %for.body], [%iv1.next, %subloop1]
%iv1.next = add i32 %iv1, 1
%addr1 = call double* @get_addr(i32 %iv1)
store double 0.0, double* %addr1
%cmp1 = icmp slt i32 %iv1, 200
br i1 %cmp1, label %subloop1, label %for.latch
subloop2:
%iv2 = phi i32 [400, %for.body], [%iv2.next, %subloop2]
%iv2.next = add i32 %iv2, 1
%addr2 = call double* @get_addr(i32 %iv2)
store double 0.0, double* %addr2
%cmp2 = icmp slt i32 %iv2, 600
br i1 %cmp2, label %subloop2, label %for.latch
for.latch:
br label %for.body
for.end:
ret void
}
; CHECK-LABEL: Function: test_dom: 3 pointers, 0 call sites
; CHECK: MayAlias: double* %addr1, double* %data
; CHECK: NoAlias: double* %addr2, double* %data
; CHECK: NoAlias: double* %addr1, double* %addr2
; This is a variant of test_non_dom where the second subloop is
; dominated by the first. As a result of that, we can nest the
; addrecs and cancel out the %data base pointer.
define void @test_dom(double* %data) {
entry:
load double, double* %data
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.latch ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br label %subloop1
subloop1:
%iv1 = phi i32 [0, %for.body], [%iv1.next, %subloop1]
%iv1.next = add i32 %iv1, 1
%addr1 = getelementptr double, double* %data, i32 %iv1
store double 0.0, double* %addr1
%cmp1 = icmp slt i32 %iv1, 200
br i1 %cmp1, label %subloop1, label %subloop2
subloop2:
%iv2 = phi i32 [400, %subloop1], [%iv2.next, %subloop2]
%iv2.next = add i32 %iv2, 1
%addr2 = getelementptr double, double* %data, i32 %iv2
store double 0.0, double* %addr2
%cmp2 = icmp slt i32 %iv2, 600
br i1 %cmp2, label %subloop2, label %for.latch
for.latch:
br label %for.body
for.end:
ret void
}