stacksaverestore.ll
3.49 KB
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; RUN: opt < %s -instcombine -S | FileCheck %s
@glob = global i32 0
declare i8* @llvm.stacksave()
declare void @llvm.stackrestore(i8*)
;; Test that llvm.stackrestore is removed when possible.
define i32* @test1(i32 %P) {
%tmp = call i8* @llvm.stacksave( )
call void @llvm.stackrestore( i8* %tmp ) ;; not restoring anything
%A = alloca i32, i32 %P
ret i32* %A
}
; CHECK-LABEL: define i32* @test1(
; CHECK-NOT: call void @llvm.stackrestore
; CHECK: ret i32*
define void @test2(i8* %X) {
call void @llvm.stackrestore( i8* %X ) ;; no allocas before return.
ret void
}
; CHECK-LABEL: define void @test2(
; CHECK-NOT: call void @llvm.stackrestore
; CHECK: ret void
define void @foo(i32 %size) nounwind {
entry:
%tmp118124 = icmp sgt i32 %size, 0 ; <i1> [#uses=1]
br i1 %tmp118124, label %bb.preheader, label %return
bb.preheader: ; preds = %entry
%tmp25 = add i32 %size, -1 ; <i32> [#uses=1]
%tmp125 = icmp slt i32 %size, 1 ; <i1> [#uses=1]
%smax = select i1 %tmp125, i32 1, i32 %size ; <i32> [#uses=1]
br label %bb
bb: ; preds = %bb, %bb.preheader
%i.0.reg2mem.0 = phi i32 [ 0, %bb.preheader ], [ %indvar.next, %bb ] ; <i32> [#uses=2]
%tmp = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
%tmp23 = alloca i8, i32 %size ; <i8*> [#uses=2]
%tmp27 = getelementptr i8, i8* %tmp23, i32 %tmp25 ; <i8*> [#uses=1]
store i8 0, i8* %tmp27, align 1
%tmp28 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
%tmp52 = alloca i8, i32 %size ; <i8*> [#uses=1]
%tmp53 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
%tmp77 = alloca i8, i32 %size ; <i8*> [#uses=1]
%tmp78 = call i8* @llvm.stacksave( ) ; <i8*> [#uses=1]
%tmp102 = alloca i8, i32 %size ; <i8*> [#uses=1]
call void @bar( i32 %i.0.reg2mem.0, i8* %tmp23, i8* %tmp52, i8* %tmp77, i8* %tmp102, i32 %size ) nounwind
call void @llvm.stackrestore( i8* %tmp78 )
call void @llvm.stackrestore( i8* %tmp53 )
call void @llvm.stackrestore( i8* %tmp28 )
call void @llvm.stackrestore( i8* %tmp )
%indvar.next = add i32 %i.0.reg2mem.0, 1 ; <i32> [#uses=2]
%exitcond = icmp eq i32 %indvar.next, %smax ; <i1> [#uses=1]
br i1 %exitcond, label %return, label %bb
return: ; preds = %bb, %entry
ret void
}
; CHECK-LABEL: define void @foo(
; CHECK: %tmp = call i8* @llvm.stacksave()
; CHECK: alloca i8
; CHECK-NOT: stacksave
; CHECK: call void @bar(
; CHECK-NEXT: call void @llvm.stackrestore(i8* %tmp)
; CHECK: ret void
declare void @bar(i32, i8*, i8*, i8*, i8*, i32)
declare void @inalloca_callee(i32* inalloca)
define void @test3(i32 %c) {
entry:
br label %loop
loop:
%i = phi i32 [0, %entry], [%i1, %loop]
%save1 = call i8* @llvm.stacksave()
%argmem = alloca inalloca i32
store i32 0, i32* %argmem
call void @inalloca_callee(i32* inalloca %argmem)
; This restore cannot be deleted, the restore below does not make it dead.
call void @llvm.stackrestore(i8* %save1)
; FIXME: We should be able to remove this save/restore pair, but we don't.
%save2 = call i8* @llvm.stacksave()
store i32 0, i32* @glob
call void @llvm.stackrestore(i8* %save2)
%i1 = add i32 1, %i
%done = icmp eq i32 %i1, %c
br i1 %done, label %loop, label %return
return:
ret void
}
; CHECK-LABEL: define void @test3(
; CHECK: loop:
; CHECK: %i = phi i32 [ 0, %entry ], [ %i1, %loop ]
; CHECK: %save1 = call i8* @llvm.stacksave()
; CHECK: %argmem = alloca inalloca i32
; CHECK: store i32 0, i32* %argmem
; CHECK: call void @inalloca_callee(i32* inalloca {{.*}} %argmem)
; CHECK: call void @llvm.stackrestore(i8* %save1)
; CHECK: br i1 %done, label %loop, label %return
; CHECK: ret void