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llvm-mirror/test/Analysis/AliasSet/argmemonly.ll
Nikita Popov 0e6a699715 [AA] Split up LocationSize::unknown()
Currently, we have some confusion in the codebase regarding the
meaning of LocationSize::unknown(): Some parts (including most of
BasicAA) assume that LocationSize::unknown() only allows accesses
after the base pointer. Some parts (various callers of AA) assume
that LocationSize::unknown() allows accesses both before and after
the base pointer (but within the underlying object).

This patch splits up LocationSize::unknown() into
LocationSize::afterPointer() and LocationSize::beforeOrAfterPointer()
to make this completely unambiguous. I tried my best to determine
which one is appropriate for all the existing uses.

The test changes in cs-cs.ll in particular illustrate a previously
clearly incorrect AA result: We were effectively assuming that
argmemonly functions were only allowed to access their arguments
after the passed pointer, but not before it. I'm pretty sure that
this was not intentional, and it's certainly not specified by
LangRef that way.

Differential Revision: https://reviews.llvm.org/D91649
2020-11-26 18:39:55 +01:00

136 lines
5.5 KiB
LLVM

; RUN: opt -basic-aa -print-alias-sets -S -o - < %s 2>&1 | FileCheck %s
@s = global i8 1, align 1
@d = global i8 2, align 1
; CHECK: Alias sets for function 'test_alloca_argmemonly':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 3 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %a, LocationSize::precise(1))
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 2] may alias, Mod/Ref Pointers: (i8* %d, unknown before-or-after), (i8* %s, unknown before-or-after)
define void @test_alloca_argmemonly(i8* %s, i8* %d) {
entry:
%a = alloca i8, align 1
store i8 1, i8* %a, align 1
call void @my_memcpy(i8* %d, i8* %s, i64 1)
ret void
}
; CHECK: Alias sets for function 'test_readonly_arg'
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %d, unknown before-or-after)
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Ref Pointers: (i8* %s, unknown before-or-after)
define i8 @test_readonly_arg(i8* noalias %s, i8* noalias %d) {
entry:
call void @my_memcpy(i8* %d, i8* %s, i64 1)
%ret = load i8, i8* %s
ret i8 %ret
}
; CHECK: Alias sets for function 'test_noalias_argmemonly':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 3 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %a, LocationSize::precise(1))
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 2] may alias, Mod/Ref Pointers: (i8* %d, unknown before-or-after), (i8* %s, unknown before-or-after)
define void @test_noalias_argmemonly(i8* noalias %a, i8* %s, i8* %d) {
entry:
store i8 1, i8* %a, align 1
call void @my_memmove(i8* %d, i8* %s, i64 1)
ret void
}
; CHECK: Alias sets for function 'test5':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod/Ref Pointers: (i8* %a, unknown before-or-after)
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %b, unknown before-or-after)
define void @test5(i8* noalias %a, i8* noalias %b) {
entry:
store i8 1, i8* %a, align 1
call void @my_memcpy(i8* %b, i8* %a, i64 1)
store i8 1, i8* %b, align 1
ret void
}
; CHECK: Alias sets for function 'test_argcollapse':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod/Ref Pointers: (i8* %a, unknown before-or-after)
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod/Ref Pointers: (i8* %b, unknown before-or-after)
define void @test_argcollapse(i8* noalias %a, i8* noalias %b) {
entry:
store i8 1, i8* %a, align 1
call void @my_memmove(i8* %b, i8* %a, i64 1)
store i8 1, i8* %b, align 1
ret void
}
; CHECK: Alias sets for function 'test_memcpy1':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod/Ref Pointers: (i8* %b, unknown before-or-after)
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod/Ref Pointers: (i8* %a, unknown before-or-after)
define void @test_memcpy1(i8* noalias %a, i8* noalias %b) {
entry:
call void @my_memcpy(i8* %b, i8* %a, i64 1)
call void @my_memcpy(i8* %a, i8* %b, i64 1)
ret void
}
; CHECK: Alias sets for function 'test_memset1':
; CHECK-NEXT: Alias Set Tracker: 1 alias sets for 1 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %a, unknown before-or-after)
define void @test_memset1() {
entry:
%a = alloca i8, align 1
call void @my_memset(i8* %a, i8 0, i64 1)
ret void
}
; CHECK: Alias sets for function 'test_memset2':
; CHECK-NEXT: Alias Set Tracker: 1 alias sets for 1 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %a, unknown before-or-after)
define void @test_memset2(i8* %a) {
entry:
call void @my_memset(i8* %a, i8 0, i64 1)
ret void
}
; CHECK: Alias sets for function 'test_memset3':
; CHECK-NEXT: Alias Set Tracker: 1 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 2] may alias, Mod Pointers: (i8* %a, unknown before-or-after), (i8* %b, unknown before-or-after)
define void @test_memset3(i8* %a, i8* %b) {
entry:
call void @my_memset(i8* %a, i8 0, i64 1)
call void @my_memset(i8* %b, i8 0, i64 1)
ret void
}
;; PICKUP HERE
; CHECK: Alias sets for function 'test_memset4':
; CHECK-NEXT: Alias Set Tracker: 2 alias sets for 2 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %a, unknown before-or-after)
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod Pointers: (i8* %b, unknown before-or-after)
define void @test_memset4(i8* noalias %a, i8* noalias %b) {
entry:
call void @my_memset(i8* %a, i8 0, i64 1)
call void @my_memset(i8* %b, i8 0, i64 1)
ret void
}
declare void @my_memset(i8* nocapture writeonly, i8, i64) argmemonly
declare void @my_memcpy(i8* nocapture writeonly, i8* nocapture readonly, i64) argmemonly
declare void @my_memmove(i8* nocapture, i8* nocapture readonly, i64) argmemonly
; CHECK: Alias sets for function 'test_attribute_intersect':
; CHECK-NEXT: Alias Set Tracker: 1 alias sets for 1 pointer values.
; CHECK-NEXT: AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Ref Pointers: (i8* %a, LocationSize::precise(1))
define i8 @test_attribute_intersect(i8* noalias %a) {
entry:
;; This call is effectively readnone since the argument is readonly
;; and the function is declared writeonly.
call void @attribute_intersect(i8* %a)
%val = load i8, i8* %a
ret i8 %val
}
declare void @attribute_intersect(i8* readonly) argmemonly writeonly