2007-08-27-VolatileLoadsStores.ll   [plain text]

; RUN: llvm-as < %s | opt -std-compile-opts | llvm-dis | grep volatile | count 3
; PR1520
; Don't promote volatile loads/stores. This is really needed to handle setjmp/lonjmp properly.

target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
target triple = "i686-pc-linux-gnu"
	%struct.__jmp_buf_tag = type { [6 x i32], i32, %struct.__sigset_t }
	%struct.__sigset_t = type { [32 x i32] }
@j = external global [1 x %struct.__jmp_buf_tag]		; <[1 x %struct.__jmp_buf_tag]*> [#uses=1]

define i32 @f() {
entry:
	%retval = alloca i32, align 4		; <i32*> [#uses=2]
	%v = alloca i32, align 4		; <i32*> [#uses=3]
	%tmp = alloca i32, align 4		; <i32*> [#uses=3]
	%"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
	volatile store i32 0, i32* %v, align 4
	%tmp1 = call i32 @_setjmp( %struct.__jmp_buf_tag* getelementptr ([1 x %struct.__jmp_buf_tag]* @j, i32 0, i32 0) )		; <i32> [#uses=1]
	%tmp2 = icmp ne i32 %tmp1, 0		; <i1> [#uses=1]
	%tmp23 = zext i1 %tmp2 to i8		; <i8> [#uses=1]
	%toBool = icmp ne i8 %tmp23, 0		; <i1> [#uses=1]
	br i1 %toBool, label %bb, label %bb5

bb:		; preds = %entry
	%tmp4 = volatile load i32* %v, align 4		; <i32> [#uses=1]
	store i32 %tmp4, i32* %tmp, align 4
	br label %bb6

bb5:		; preds = %entry
	volatile store i32 1, i32* %v, align 4
	call void @g( )
	store i32 0, i32* %tmp, align 4
	br label %bb6

bb6:		; preds = %bb5, %bb
	%tmp7 = load i32* %tmp, align 4		; <i32> [#uses=1]
	store i32 %tmp7, i32* %retval, align 4
	br label %return

return:		; preds = %bb6
	%retval8 = load i32* %retval		; <i32> [#uses=1]
	ret i32 %retval8
}

declare i32 @_setjmp(%struct.__jmp_buf_tag*)

declare void @g()