1 ; RUN: opt < %s -instcombine -S | FileCheck %s 2 3 @glob = global i32 0 4 5 declare i8* @llvm.stacksave() 6 declare void @llvm.stackrestore(i8*) 7 8 ;; Test that llvm.stackrestore is removed when possible. 9 define i32* @test1(i32 %P) { 10 %tmp = call i8* @llvm.stacksave( ) 11 call void @llvm.stackrestore( i8* %tmp ) ;; not restoring anything 12 %A = alloca i32, i32 %P 13 ret i32* %A 14 } 15 16 ; CHECK-LABEL: define i32* @test1( 17 ; CHECK-NOT: call void @llvm.stackrestore 18 ; CHECK: ret i32* 19 20 define void @test2(i8* %X) { 21 call void @llvm.stackrestore( i8* %X ) ;; no allocas before return. 22 ret void 23 } 24 25 ; CHECK-LABEL: define void @test2( 26 ; CHECK-NOT: call void @llvm.stackrestore 27 ; CHECK: ret void 28 29 define void @foo(i32 %size) nounwind { 30 entry: 31 %tmp118124 = icmp sgt i32 %size, 0 ; <i1> [#uses=1] 32 br i1 %tmp118124, label %bb.preheader, label %return 33 34 bb.preheader: ; preds = %entry 35 %tmp25 = add i32 %size, -1 ; <i32> [#uses=1] 36 %tmp125 = icmp slt i32 %size, 1 ; <i1> [#uses=1] 37 %smax = select i1 %tmp125, i32 1, i32 %size ; <i32> [#uses=1] 38 br label %bb 39 40 bb: ; preds = %bb, %bb.preheader 41 %i.0.reg2mem.0 = phi i32 [ 0, %bb.preheader ], [ %indvar.next, %bb ] ; <i32> [#uses=2] 42 %tmp = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1] 43 %tmp23 = alloca i8, i32 %size ; <i8*> [#uses=2] 44 %tmp27 = getelementptr i8, i8* %tmp23, i32 %tmp25 ; <i8*> [#uses=1] 45 store i8 0, i8* %tmp27, align 1 46 %tmp28 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1] 47 %tmp52 = alloca i8, i32 %size ; <i8*> [#uses=1] 48 %tmp53 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1] 49 %tmp77 = alloca i8, i32 %size ; <i8*> [#uses=1] 50 %tmp78 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1] 51 %tmp102 = alloca i8, i32 %size ; <i8*> [#uses=1] 52 call void @bar( i32 %i.0.reg2mem.0, i8* %tmp23, i8* %tmp52, i8* %tmp77, i8* %tmp102, i32 %size ) nounwind 53 call void @llvm.stackrestore( i8* %tmp78 ) 54 call void @llvm.stackrestore( i8* %tmp53 ) 55 call void @llvm.stackrestore( i8* %tmp28 ) 56 call void @llvm.stackrestore( i8* %tmp ) 57 %indvar.next = add i32 %i.0.reg2mem.0, 1 ; <i32> [#uses=2] 58 %exitcond = icmp eq i32 %indvar.next, %smax ; <i1> [#uses=1] 59 br i1 %exitcond, label %return, label %bb 60 61 return: ; preds = %bb, %entry 62 ret void 63 } 64 65 ; CHECK-LABEL: define void @foo( 66 ; CHECK: %tmp = call i8* @llvm.stacksave() 67 ; CHECK: alloca i8 68 ; CHECK-NOT: stacksave 69 ; CHECK: call void @bar( 70 ; CHECK-NEXT: call void @llvm.stackrestore(i8* %tmp) 71 ; CHECK: ret void 72 73 declare void @bar(i32, i8*, i8*, i8*, i8*, i32) 74 75 declare void @inalloca_callee(i32* inalloca) 76 77 define void @test3(i32 %c) { 78 entry: 79 br label %loop 80 81 loop: 82 %i = phi i32 [0, %entry], [%i1, %loop] 83 %save1 = call i8* @llvm.stacksave() 84 %argmem = alloca inalloca i32 85 store i32 0, i32* %argmem 86 call void @inalloca_callee(i32* inalloca %argmem) 87 88 ; This restore cannot be deleted, the restore below does not make it dead. 89 call void @llvm.stackrestore(i8* %save1) 90 91 ; FIXME: We should be able to remove this save/restore pair, but we don't. 92 %save2 = call i8* @llvm.stacksave() 93 store i32 0, i32* @glob 94 call void @llvm.stackrestore(i8* %save2) 95 %i1 = add i32 1, %i 96 %done = icmp eq i32 %i1, %c 97 br i1 %done, label %loop, label %return 98 99 return: 100 ret void 101 } 102 103 ; CHECK-LABEL: define void @test3( 104 ; CHECK: loop: 105 ; CHECK: %i = phi i32 [ 0, %entry ], [ %i1, %loop ] 106 ; CHECK: %save1 = call i8* @llvm.stacksave() 107 ; CHECK: %argmem = alloca inalloca i32 108 ; CHECK: store i32 0, i32* %argmem 109 ; CHECK: call void @inalloca_callee(i32* inalloca {{.*}} %argmem) 110 ; CHECK: call void @llvm.stackrestore(i8* %save1) 111 ; CHECK: br i1 %done, label %loop, label %return 112 ; CHECK: ret void 113
