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[BasicAA] Add test for incorrectly inferring noalias due to scale sign.

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This patch adds a test where we currently incorrectly determine noalias,
because the sign of Scale is adjusted after 91fa3565da16.
This commit is contained in:
Florian Hahn 2021-06-30 18:00:36 +01:00
parent a277ada21c
commit 78eb09629d
1 changed files with 29 additions and 0 deletions
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29
test/Analysis/BasicAA/gep-modulo.ll
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@ -273,3 +273,32 @@ define void @may_overflow_pointer_diff([16 x i8]* %ptr, i64 %idx) {
ret void
}
; %gep.1 and %gep.idx may alias, e.g. if %idx.1 = 8 and %idx.2 == 2. %gep.idx is then
; (((18446744073709551614 * 8) % 2^64 + 6 * 2) % 2^64 + 10) % 2^64 == 6.
define void @may_overflow_mul_scale_neg([200 x [ 6 x i8]]* %ptr, i64 %idx.1,i64 %idx.2) {
; CHECK-LABEL: Function: may_overflow_mul_scale_neg: 4 pointers, 2 call sites
; CHECK-NEXT: MustAlias: [200 x [6 x i8]]* %ptr, i8* %bc
; CHECK-NEXT: PartialAlias (off 6): [200 x [6 x i8]]* %ptr, i8* %gep.1
; CHECK-NEXT: NoAlias: i8* %bc, i8* %gep.1
; CHECK-NEXT: MayAlias: [200 x [6 x i8]]* %ptr, i8* %gep.idx
; CHECK-NEXT: NoAlias: i8* %bc, i8* %gep.idx
; CHECK-NEXT: NoAlias: i8* %gep.1, i8* %gep.idx
;
%idx.1.pos = icmp sge i64 %idx.1, 0
call void @llvm.assume(i1 %idx.1.pos)
%idx.2.pos = icmp sge i64 %idx.2, 0
call void @llvm.assume(i1 %idx.2.pos)
%bc = bitcast [ 200 x [ 6 x i8 ] ]* %ptr to i8*
%gep.1 = getelementptr i8, i8* %bc, i64 6
store i8 1, i8* %gep.1, align 1
%mul.0 = mul i64 %idx.1, -2
%add = add i64 %mul.0, 10
%gep.idx = getelementptr [ 200 x [ 6 x i8 ] ], [ 200 x [ 6 x i8 ] ]* %ptr, i64 0, i64 %idx.2, i64 %add
store i8 0, i8* %gep.idx, align 1
ret void
}
declare void @llvm.assume(i1)