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[BasicAA] Add a few cases with overflows in index computations. 

This patch adds a few test cases where currently NoAlias is returned,
but the pointers can alias if the multiply overflows while computing
a GEP index value.
This commit is contained in:
Florian Hahn 2021-03-26 14:44:13 +00:00
parent 3f6e7d1550
commit bcc8d80192
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1 changed files with 106 additions and 0 deletions
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llvm/test/Analysis/BasicAA/gep-modulo.ll Normal file
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; RUN: opt -basic-aa -aa-eval -print-all-alias-modref-info %s 2>&1 | FileCheck %s
target datalayout = "p:64:64:64"
; %gep.idx and %gep.6 must-alias if %mul overflows (e.g. %idx == 52).
define void @may_overflow_mul_add_i8([16 x i8]* %ptr, i8 %idx) {
; CHECK-LABEL: Function: may_overflow_mul_add_i8: 3 pointers, 0 call sites
; CHECK-NEXT: MayAlias: [16 x i8]* %ptr, i8* %gep.idx
; CHECK-NEXT: PartialAlias: [16 x i8]* %ptr, i8* %gep.6
; CHECK-NEXT: NoAlias: i8* %gep.6, i8* %gep.idx
;
%mul = mul i8 %idx, 5
%add = add i8 %mul, 2
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i8 %add
store i8 0, i8* %gep.idx, align 1
%gep.6 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 6
store i8 1, i8* %gep.6, align 1
ret void
}
define void @nuw_nsw_mul_add_i8([16 x i8]* %ptr, i8 %idx) {
; CHECK-LABEL: Function: nuw_nsw_mul_add_i8: 3 pointers, 0 call sites
; CHECK-NEXT: MayAlias: [16 x i8]* %ptr, i8* %gep.idx
; CHECK-NEXT: PartialAlias: [16 x i8]* %ptr, i8* %gep.6
; CHECK-NEXT: NoAlias: i8* %gep.6, i8* %gep.idx
;
%mul = mul nuw nsw i8 %idx, 5
%add = add nuw nsw i8 %mul, 2
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i8 %add
store i8 0, i8* %gep.idx, align 1
%gep.6 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 6
store i8 1, i8* %gep.6, align 1
ret void
}
; %gep.idx and %gep.3 must-alias if %mul overflows (e.g. %idx == 52).
define void @may_overflow_mul_sub_i8([16 x i8]* %ptr, i8 %idx) {
; CHECK-LABEL: Function: may_overflow_mul_sub_i8: 3 pointers, 0 call sites
; CHECK-NEXT: MayAlias: [16 x i8]* %ptr, i8* %gep.idx
; CHECK-NEXT: PartialAlias: [16 x i8]* %ptr, i8* %gep.3
; CHECK-NEXT: NoAlias: i8* %gep.3, i8* %gep.idx
;
%mul = mul i8 %idx, 5
%sub = sub i8 %mul, 1
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i8 %sub
store i8 0, i8* %gep.idx, align 1
%gep.3 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 3
store i8 1, i8* %gep.3, align 1
ret void
}
define void @nuw_nsw_mul_sub_i8([16 x i8]* %ptr, i8 %idx) {
%mul = mul i8 %idx, 5
%sub = sub i8 %mul, 1
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i8 %sub
store i8 0, i8* %gep.idx, align 1
%gep.3 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 3
store i8 1, i8* %gep.3, align 1
ret void
}
; %gep.idx and %gep.3 must-alias if %mul overflows
; (e.g. %idx == 3689348814741910323).
define void @may_overflow_mul_sub_i64([16 x i8]* %ptr, i64 %idx) {
%mul = mul i64 %idx, 5
%sub = sub i64 %mul, 1
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i64 %sub
store i8 0, i8* %gep.idx, align 1
%gep.3 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i64 3
store i8 1, i8* %gep.3, align 1
ret void
}
; %gep.idx and %gep.3 must-alias if %mul overflows (e.g. %idx == 110).
define void @may_overflow_i32_sext([16 x i8]* %ptr, i32 %idx) {
; CHECK-LABEL: Function: may_overflow_i32_sext: 3 pointers, 0 call sites
; CHECK-NEXT: MayAlias: [16 x i8]* %ptr, i8* %gep.idx
; CHECK-NEXT: PartialAlias: [16 x i8]* %ptr, i8* %gep.3
; CHECK-NEXT: MayAlias: i8* %gep.3, i8* %gep.idx
;
%mul = mul i32 %idx, 678152731
%sub = sub i32 %mul, 1582356375
%sub.ext = sext i32 %sub to i64
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i64 %sub.ext
store i8 0, i8* %gep.idx, align 1
%gep.3 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 3
store i8 1, i8* %gep.3, align 1
ret void
}
; %gep.idx and %gep.3 must-alias if %mul overflows (e.g. %idx == 110).
define void @may_overflow_i32_zext([16 x i8]* %ptr, i32 %idx) {
; CHECK-LABEL: Function: may_overflow_i32_zext: 3 pointers, 0 call sites
; CHECK-NEXT: MayAlias: [16 x i8]* %ptr, i8* %gep.idx
; CHECK-NEXT: PartialAlias: [16 x i8]* %ptr, i8* %gep.3
; CHECK-NEXT: MayAlias: i8* %gep.3, i8* %gep.idx
;
%mul = mul i32 %idx, 678152731
%sub = sub i32 %mul, 1582356375
%sub.ext = zext i32 %sub to i64
%gep.idx = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i64 %sub.ext
store i8 0, i8* %gep.idx, align 1
%gep.3 = getelementptr [16 x i8], [16 x i8]* %ptr, i32 0, i32 3
store i8 1, i8* %gep.3, align 1
ret void
}