forked from OSchip/llvm-project
80 lines
2.1 KiB
LLVM
80 lines
2.1 KiB
LLVM
; RUN: opt -S -globalopt < %s | FileCheck %s
|
|
|
|
; This test is hint, what could globalOpt optimize and what it can't
|
|
; FIXME: @tmp and @tmp2 can be safely set to 42
|
|
; CHECK: @tmp = local_unnamed_addr global i32 0
|
|
; CHECK: @tmp2 = local_unnamed_addr global i32 0
|
|
; CHECK: @tmp3 = global i32 0
|
|
|
|
@tmp = global i32 0
|
|
@tmp2 = global i32 0
|
|
@tmp3 = global i32 0
|
|
@ptrToTmp3 = global i32* null
|
|
|
|
@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @_GLOBAL__I_a }]
|
|
|
|
define i32 @TheAnswerToLifeTheUniverseAndEverything() {
|
|
ret i32 42
|
|
}
|
|
|
|
define void @_GLOBAL__I_a() {
|
|
enter:
|
|
call void @_optimizable()
|
|
call void @_not_optimizable()
|
|
ret void
|
|
}
|
|
|
|
define void @_optimizable() {
|
|
enter:
|
|
%valptr = alloca i32
|
|
|
|
%val = call i32 @TheAnswerToLifeTheUniverseAndEverything()
|
|
store i32 %val, i32* @tmp
|
|
store i32 %val, i32* %valptr
|
|
|
|
%0 = bitcast i32* %valptr to i8*
|
|
%barr = call i8* @llvm.launder.invariant.group(i8* %0)
|
|
%1 = bitcast i8* %barr to i32*
|
|
|
|
%val2 = load i32, i32* %1
|
|
store i32 %val2, i32* @tmp2
|
|
ret void
|
|
}
|
|
|
|
; We can't step through launder.invariant.group here, because that would change
|
|
; this load in @usage_of_globals()
|
|
; val = load i32, i32* %ptrVal, !invariant.group !0
|
|
; into
|
|
; %val = load i32, i32* @tmp3, !invariant.group !0
|
|
; and then we could assume that %val and %val2 to be the same, which coud be
|
|
; false, because @changeTmp3ValAndCallBarrierInside() may change the value
|
|
; of @tmp3.
|
|
define void @_not_optimizable() {
|
|
enter:
|
|
store i32 13, i32* @tmp3, !invariant.group !0
|
|
|
|
%0 = bitcast i32* @tmp3 to i8*
|
|
%barr = call i8* @llvm.launder.invariant.group(i8* %0)
|
|
%1 = bitcast i8* %barr to i32*
|
|
|
|
store i32* %1, i32** @ptrToTmp3
|
|
store i32 42, i32* %1, !invariant.group !0
|
|
|
|
ret void
|
|
}
|
|
define void @usage_of_globals() {
|
|
entry:
|
|
%ptrVal = load i32*, i32** @ptrToTmp3
|
|
%val = load i32, i32* %ptrVal, !invariant.group !0
|
|
|
|
call void @changeTmp3ValAndCallBarrierInside()
|
|
%val2 = load i32, i32* @tmp3, !invariant.group !0
|
|
ret void;
|
|
}
|
|
|
|
declare void @changeTmp3ValAndCallBarrierInside()
|
|
|
|
declare i8* @llvm.launder.invariant.group(i8*)
|
|
|
|
!0 = !{}
|