YouCompleteMe/cpp/llvm/test/Transforms/LICM/2003-05-02-LoadHoist.ll
2012-07-05 17:51:06 -07:00

24 lines
685 B
LLVM

; This testcase tests for a problem where LICM hoists loads out of a loop
; despite the fact that calls to unknown functions may modify what is being
; loaded from. Basically if the load gets hoisted, the subtract gets turned
; into a constant zero.
;
; RUN: opt < %s -licm -gvn -instcombine -S | grep load
@X = global i32 7 ; <i32*> [#uses=2]
declare void @foo()
define i32 @test(i1 %c) {
%A = load i32* @X ; <i32> [#uses=1]
br label %Loop
Loop: ; preds = %Loop, %0
call void @foo( )
;; Should not hoist this load!
%B = load i32* @X ; <i32> [#uses=1]
br i1 %c, label %Loop, label %Out
Out: ; preds = %Loop
%C = sub i32 %A, %B ; <i32> [#uses=1]
ret i32 %C
}