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llvm-mirror/test/Analysis/BasicAA/modref.ll
Igor Laevsky 05bff16edd Add argmemonly attribute.
This change adds new attribute called "argmemonly". Function marked with this attribute can only access memory through it's argument pointers. This attribute directly corresponds to the "OnlyAccessesArgumentPointees" ModRef behaviour in alias analysis.

Differential Revision: http://reviews.llvm.org/D10398

llvm-svn: 241979
2015-07-11 10:30:36 +00:00

197 lines
5.0 KiB
LLVM

; RUN: opt < %s -basicaa -gvn -dse -S | FileCheck %s
target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
declare void @llvm.lifetime.end(i64, i8* nocapture)
declare void @external(i32*)
define i32 @test0(i8* %P) {
%A = alloca i32
call void @external(i32* %A)
store i32 0, i32* %A
call void @llvm.memset.p0i8.i32(i8* %P, i8 0, i32 42, i32 1, i1 false)
%B = load i32, i32* %A
ret i32 %B
; CHECK-LABEL: @test0
; CHECK: ret i32 0
}
define i8 @test1() {
; CHECK-LABEL: @test1
%A = alloca i8
%B = alloca i8
store i8 2, i8* %B ;; Not written to by memcpy
call void @llvm.memcpy.p0i8.p0i8.i8(i8* %A, i8* %B, i8 -1, i32 0, i1 false)
%C = load i8, i8* %B
ret i8 %C
; CHECK: ret i8 2
}
define i8 @test2(i8* %P) {
; CHECK-LABEL: @test2
%P2 = getelementptr i8, i8* %P, i32 127
store i8 1, i8* %P2 ;; Not dead across memset
call void @llvm.memset.p0i8.i8(i8* %P, i8 2, i8 127, i32 0, i1 false)
%A = load i8, i8* %P2
ret i8 %A
; CHECK: ret i8 1
}
define i8 @test2a(i8* %P) {
; CHECK-LABEL: @test2
%P2 = getelementptr i8, i8* %P, i32 126
;; FIXME: DSE isn't zapping this dead store.
store i8 1, i8* %P2 ;; Dead, clobbered by memset.
call void @llvm.memset.p0i8.i8(i8* %P, i8 2, i8 127, i32 0, i1 false)
%A = load i8, i8* %P2
ret i8 %A
; CHECK-NOT: load
; CHECK: ret i8 2
}
define void @test3(i8* %P, i8 %X) {
; CHECK-LABEL: @test3
; CHECK-NOT: store
; CHECK-NOT: %Y
%Y = add i8 %X, 1 ;; Dead, because the only use (the store) is dead.
%P2 = getelementptr i8, i8* %P, i32 2
store i8 %Y, i8* %P2 ;; Not read by lifetime.end, should be removed.
; CHECK: store i8 2, i8* %P2
call void @llvm.lifetime.end(i64 1, i8* %P)
store i8 2, i8* %P2
; CHECK-NOT: store
ret void
; CHECK: ret void
}
define void @test3a(i8* %P, i8 %X) {
; CHECK-LABEL: @test3a
%Y = add i8 %X, 1 ;; Dead, because the only use (the store) is dead.
%P2 = getelementptr i8, i8* %P, i32 2
store i8 %Y, i8* %P2
; CHECK-NEXT: call void @llvm.lifetime.end
call void @llvm.lifetime.end(i64 10, i8* %P)
ret void
; CHECK-NEXT: ret void
}
@G1 = external global i32
@G2 = external global [4000 x i32]
define i32 @test4(i8* %P) {
%tmp = load i32, i32* @G1
call void @llvm.memset.p0i8.i32(i8* bitcast ([4000 x i32]* @G2 to i8*), i8 0, i32 4000, i32 1, i1 false)
%tmp2 = load i32, i32* @G1
%sub = sub i32 %tmp2, %tmp
ret i32 %sub
; CHECK-LABEL: @test4
; CHECK-NOT: load
; CHECK: memset.p0i8.i32
; CHECK-NOT: load
; CHECK: ret i32 0
}
; Verify that basicaa is handling variable length memcpy, knowing it doesn't
; write to G1.
define i32 @test5(i8* %P, i32 %Len) {
%tmp = load i32, i32* @G1
call void @llvm.memcpy.p0i8.p0i8.i32(i8* bitcast ([4000 x i32]* @G2 to i8*), i8* bitcast (i32* @G1 to i8*), i32 %Len, i32 1, i1 false)
%tmp2 = load i32, i32* @G1
%sub = sub i32 %tmp2, %tmp
ret i32 %sub
; CHECK: @test5
; CHECK-NOT: load
; CHECK: memcpy.p0i8.p0i8.i32
; CHECK-NOT: load
; CHECK: ret i32 0
}
define i8 @test6(i8* %p, i8* noalias %a) {
%x = load i8, i8* %a
%t = va_arg i8* %p, float
%y = load i8, i8* %a
%z = add i8 %x, %y
ret i8 %z
; CHECK-LABEL: @test6
; CHECK: load i8, i8* %a
; CHECK-NOT: load
; CHECK: ret
}
; PR10628
declare void @test7decl(i32* nocapture %x)
define i32 @test7() nounwind uwtable ssp {
entry:
%x = alloca i32, align 4
store i32 0, i32* %x, align 4
%add.ptr = getelementptr inbounds i32, i32* %x, i64 1
call void @test7decl(i32* %add.ptr)
%tmp = load i32, i32* %x, align 4
ret i32 %tmp
; CHECK-LABEL: @test7(
; CHECK: store i32 0
; CHECK: call void @test7decl
; CHECK: load i32, i32*
}
;; Check that aa correctly handles functions marked with argmemonly
;; attribute.
declare i32 @func_argmemonly(i32 * %P) argmemonly
;; Can not remove redundant load, function may write to it.
; CHECK-LABEL: @test8(
define i32 @test8(i32 *%P) {
%V1 = load i32, i32* %P
call i32 @func_argmemonly(i32* %P)
%V2 = load i32, i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: load
; CHECK: load
; CHECK: sub
; CHECK: ret i32 %Diff
}
;; In this case load can be removed, function clobbers only %P2.
; CHECK-LABEL: @test9(
define i32 @test9(i32* %P, i32* noalias %P2) {
%V1 = load i32, i32* %P
call i32 @func_argmemonly(i32* %P2)
%V2 = load i32, i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK-NOT: load
; CHECK: ret i32 0
}
;; In this case load can *not* be removed. Function clobers only %P2 but it may
;; alias with %P.
; CHECK-LABEL: @test10(
define i32 @test10(i32* %P, i32* %P2) {
%V1 = load i32, i32* %P
call i32 @func_argmemonly(i32* %P2)
%V2 = load i32, i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: load
; CHECK: load
; CHECK: sub
; CHECK: ret i32 %Diff
}
declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
declare void @llvm.memset.p0i8.i8(i8* nocapture, i8, i8, i32, i1) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i8(i8* nocapture, i8* nocapture, i8, i32, i1) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind