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llvm-project/llvm/test/Analysis/BasicAA/zext.ll
Nikita Popov cb4fc25c91 [BasicAA] Make alias GEP positive offset handling symmetric 
aliasGEP() currently implements some special handling for the case
where all variable offsets are positive, in which case the constant
offset can be taken as the minimal offset. However, it does not
perform the same handling for the all-negative case. This means that
the alias-analysis result between two GEPs is asymmetric:
If GEP1 - GEP2 is all-positive, then GEP2 - GEP1 is all-negative,
and the first will result in NoAlias, while the second will result
in MayAlias.

Apart from producing sub-optimal results for one order, this also
violates our caching assumption. In particular, if BatchAA is used,
the cached result depends on the order of the GEPs in the first query.
This results in an inconsistency in BatchAA and AA results, which
is how I noticed this issue in the first place.

Differential Revision: https://reviews.llvm.org/D91383
2020-11-17 18:05:34 +01:00

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; RUN: opt < %s -basic-aa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
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"
target triple = "x86_64-unknown-linux-gnu"
; CHECK-LABEL: test_with_zext
; CHECK: NoAlias: i8* %a, i8* %b
define void @test_with_zext() {
%1 = tail call i8* @malloc(i64 120)
%a = getelementptr inbounds i8, i8* %1, i64 8
%2 = getelementptr inbounds i8, i8* %1, i64 16
%3 = zext i32 3 to i64
%b = getelementptr inbounds i8, i8* %2, i64 %3
ret void
}
; CHECK-LABEL: test_with_lshr
; CHECK: NoAlias: i8* %a, i8* %b
define void @test_with_lshr(i64 %i) {
%1 = tail call i8* @malloc(i64 120)
%a = getelementptr inbounds i8, i8* %1, i64 8
%2 = getelementptr inbounds i8, i8* %1, i64 16
%3 = lshr i64 %i, 2
%b = getelementptr inbounds i8, i8* %2, i64 %3
ret void
}
; CHECK-LABEL: test_with_lshr_different_sizes
; CHECK: NoAlias: i16* %m2.idx, i8* %m1
define void @test_with_lshr_different_sizes(i64 %i) {
%m0 = tail call i8* @malloc(i64 120)
%m1 = getelementptr inbounds i8, i8* %m0, i64 1
%m2 = getelementptr inbounds i8, i8* %m0, i64 2
%idx = lshr i64 %i, 2
%m2.i16 = bitcast i8* %m2 to i16*
%m2.idx = getelementptr inbounds i16, i16* %m2.i16, i64 %idx
ret void
}
; CHECK-LABEL: test_with_a_loop
; CHECK: NoAlias: i8* %a, i8* %b
define void @test_with_a_loop(i8* %mem) {
br label %for.loop
for.loop:
%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
%a = getelementptr inbounds i8, i8* %mem, i64 8
%a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
%i.64 = zext i32 %i to i64
%b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
%i.plus1 = add nuw nsw i32 %i, 1
%cmp = icmp eq i32 %i.plus1, 10
br i1 %cmp, label %for.loop.exit, label %for.loop
for.loop.exit:
ret void
}
; CHECK-LABEL: test_with_varying_base_pointer_in_loop
; CHECK: NoAlias: i8* %a, i8* %b
define void @test_with_varying_base_pointer_in_loop(i8* %mem.orig) {
br label %for.loop
for.loop:
%mem = phi i8* [ %mem.orig, %0 ], [ %mem.plus1, %for.loop ]
%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
%a = getelementptr inbounds i8, i8* %mem, i64 8
%a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
%i.64 = zext i32 %i to i64
%b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
%i.plus1 = add nuw nsw i32 %i, 1
%mem.plus1 = getelementptr inbounds i8, i8* %mem, i64 8
%cmp = icmp eq i32 %i.plus1, 10
br i1 %cmp, label %for.loop.exit, label %for.loop
for.loop.exit:
ret void
}
; CHECK-LABEL: test_sign_extension
; CHECK: MayAlias: i64* %b.i64, i8* %a
define void @test_sign_extension(i32 %p) {
%1 = tail call i8* @malloc(i64 120)
%p.64 = zext i32 %p to i64
%a = getelementptr inbounds i8, i8* %1, i64 %p.64
%p.minus1 = add i32 %p, -1
%p.minus1.64 = zext i32 %p.minus1 to i64
%b.i8 = getelementptr inbounds i8, i8* %1, i64 %p.minus1.64
%b.i64 = bitcast i8* %b.i8 to i64*
ret void
}
; CHECK-LABEL: test_fe_tools
; CHECK: MayAlias: i32* %a, i32* %b
define void @test_fe_tools([8 x i32]* %values) {
br label %reorder
for.loop:
%i = phi i32 [ 0, %reorder ], [ %i.next, %for.loop ]
%idxprom = zext i32 %i to i64
%b = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 %idxprom
%i.next = add nuw nsw i32 %i, 1
%1 = icmp eq i32 %i.next, 10
br i1 %1, label %for.loop.exit, label %for.loop
reorder:
%a = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 1
br label %for.loop
for.loop.exit:
ret void
}
@b = global i32 0, align 4
@d = global i32 0, align 4
; CHECK-LABEL: test_spec2006
; CHECK: MayAlias: i32** %x, i32** %y
define void @test_spec2006() {
%h = alloca [1 x [2 x i32*]], align 16
%d.val = load i32, i32* @d, align 4
%d.promoted = sext i32 %d.val to i64
%1 = icmp slt i32 %d.val, 2
br i1 %1, label %.lr.ph, label %3
.lr.ph: ; preds = %0
br label %2
; <label>:2 ; preds = %.lr.ph, %2
%i = phi i32 [ %d.val, %.lr.ph ], [ %i.plus1, %2 ]
%i.promoted = sext i32 %i to i64
%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %d.promoted, i64 %i.promoted
%i.plus1 = add nsw i32 %i, 1
%cmp = icmp slt i32 %i.plus1, 2
br i1 %cmp, label %2, label %3
; <label>:3 ; preds = %._crit_edge, %0
%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
ret void
}
; CHECK-LABEL: test_modulo_analysis_easy_case
; CHECK: NoAlias: i32** %x, i32** %y
define void @test_modulo_analysis_easy_case(i64 %i) {
%h = alloca [1 x [2 x i32*]], align 16
%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i, i64 0
%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
ret void
}
; CHECK-LABEL: test_modulo_analysis_in_loop
; CHECK: NoAlias: i32** %x, i32** %y
define void @test_modulo_analysis_in_loop() {
%h = alloca [1 x [2 x i32*]], align 16
br label %for.loop
for.loop:
%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
%i.promoted = sext i32 %i to i64
%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 0
%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
%i.plus1 = add nsw i32 %i, 1
%cmp = icmp slt i32 %i.plus1, 2
br i1 %cmp, label %for.loop, label %for.loop.exit
for.loop.exit:
ret void
}
; CHECK-LABEL: test_modulo_analysis_with_global
; CHECK: MayAlias: i32** %x, i32** %y
define void @test_modulo_analysis_with_global() {
%h = alloca [1 x [2 x i32*]], align 16
%b = load i32, i32* @b, align 4
%b.promoted = sext i32 %b to i64
br label %for.loop
for.loop:
%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
%i.promoted = sext i32 %i to i64
%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 %b.promoted
%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
%i.plus1 = add nsw i32 %i, 1
%cmp = icmp slt i32 %i.plus1, 2
br i1 %cmp, label %for.loop, label %for.loop.exit
for.loop.exit:
ret void
}
; CHECK-LABEL: test_const_eval
; CHECK: NoAlias: i8* %a, i8* %b
define void @test_const_eval(i8* %ptr, i64 %offset) {
%a = getelementptr inbounds i8, i8* %ptr, i64 %offset
%a.dup = getelementptr inbounds i8, i8* %ptr, i64 %offset
%three = zext i32 3 to i64
%b = getelementptr inbounds i8, i8* %a.dup, i64 %three
ret void
}
; CHECK-LABEL: test_const_eval_scaled
; CHECK: MustAlias: i8* %a, i8* %b
define void @test_const_eval_scaled(i8* %ptr) {
%three = zext i32 3 to i64
%six = mul i64 %three, 2
%a = getelementptr inbounds i8, i8* %ptr, i64 %six
%b = getelementptr inbounds i8, i8* %ptr, i64 6
ret void
}
; CHECK-LABEL: Function: foo
; CHECK: MustAlias: float* %arrayidx, float* %arrayidx4.84
define float @foo(i32 *%A, float %rend, float** %wayar) {
entry:
%x0 = load i32, i32* %A, align 4
%conv = sext i32 %x0 to i64
%mul = shl nsw i64 %conv, 3
%call = tail call i8* @malloc(i64 %mul)
%x1 = bitcast i8* %call to float*
%sub = add nsw i32 %x0, -1
%idxprom = sext i32 %sub to i64
%arrayidx = getelementptr inbounds float, float* %x1, i64 %idxprom
store float %rend, float* %arrayidx, align 8
%indvars.iv76.83 = add nsw i64 %conv, -1
%arrayidx4.84 = getelementptr inbounds float, float* %x1, i64 %indvars.iv76.83
%x4 = load float, float* %arrayidx4.84, align 8
ret float %x4
}
; Function Attrs: nounwind
declare noalias i8* @malloc(i64)
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