test/Analysis/ScalarEvolution/scev-aa.ll - platform/external/llvm - Git at Google

 ; 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
	; 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