1 ; RUN: opt -S -globalopt < %s | FileCheck %s 2 3 ; This test is hint, what could globalOpt optimize and what it can't 4 ; FIXME: @tmp and @tmp2 can be safely set to 42 5 ; CHECK: @tmp = global i32 0 6 ; CHECK: @tmp2 = global i32 0 7 ; CHECK: @tmp3 = global i32 0 8 9 @tmp = global i32 0 10 @tmp2 = global i32 0 11 @tmp3 = global i32 0 12 @ptrToTmp3 = global i32* null 13 14 @llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @_GLOBAL__I_a }] 15 16 define i32 @TheAnswerToLifeTheUniverseAndEverything() { 17 ret i32 42 18 } 19 20 define void @_GLOBAL__I_a() { 21 enter: 22 call void @_optimizable() 23 call void @_not_optimizable() 24 ret void 25 } 26 27 define void @_optimizable() { 28 enter: 29 %valptr = alloca i32 30 31 %val = call i32 @TheAnswerToLifeTheUniverseAndEverything() 32 store i32 %val, i32* @tmp 33 store i32 %val, i32* %valptr 34 35 %0 = bitcast i32* %valptr to i8* 36 %barr = call i8* @llvm.invariant.group.barrier(i8* %0) 37 %1 = bitcast i8* %barr to i32* 38 39 %val2 = load i32, i32* %1 40 store i32 %val2, i32* @tmp2 41 ret void 42 } 43 44 ; We can't step through invariant.group.barrier here, because that would change 45 ; this load in @usage_of_globals() 46 ; val = load i32, i32* %ptrVal, !invariant.group !0 47 ; into 48 ; %val = load i32, i32* @tmp3, !invariant.group !0 49 ; and then we could assume that %val and %val2 to be the same, which coud be 50 ; false, because @changeTmp3ValAndCallBarrierInside() may change the value 51 ; of @tmp3. 52 define void @_not_optimizable() { 53 enter: 54 store i32 13, i32* @tmp3, !invariant.group !0 55 56 %0 = bitcast i32* @tmp3 to i8* 57 %barr = call i8* @llvm.invariant.group.barrier(i8* %0) 58 %1 = bitcast i8* %barr to i32* 59 60 store i32* %1, i32** @ptrToTmp3 61 store i32 42, i32* %1, !invariant.group !0 62 63 ret void 64 } 65 define void @usage_of_globals() { 66 entry: 67 %ptrVal = load i32*, i32** @ptrToTmp3 68 %val = load i32, i32* %ptrVal, !invariant.group !0 69 70 call void @changeTmp3ValAndCallBarrierInside() 71 %val2 = load i32, i32* @tmp3, !invariant.group !0 72 ret void; 73 } 74 75 declare void @changeTmp3ValAndCallBarrierInside() 76 77 declare i8* @llvm.invariant.group.barrier(i8*) 78 79 !0 = !{!"something"} 80
