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