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; RUN: opt < %s -licm -S | FileCheck %s
@X = global i32 0 ; <i32*> [#uses=1]
declare void @foo()
; This testcase tests for a problem where LICM hoists
; potentially trapping instructions when they are not guaranteed to execute.
define i32 @test1(i1 %c) {
; CHECK: @test1
%A = load i32* @X ; <i32> [#uses=2]
br label %Loop
Loop: ; preds = %LoopTail, %0
call void @foo( )
br i1 %c, label %LoopTail, label %IfUnEqual
IfUnEqual: ; preds = %Loop
; CHECK: IfUnEqual:
; CHECK-NEXT: sdiv i32 4, %A
%B1 = sdiv i32 4, %A ; <i32> [#uses=1]
br label %LoopTail
LoopTail: ; preds = %IfUnEqual, %Loop
%B = phi i32 [ 0, %Loop ], [ %B1, %IfUnEqual ] ; <i32> [#uses=1]
br i1 %c, label %Loop, label %Out
Out: ; preds = %LoopTail
%C = sub i32 %A, %B ; <i32> [#uses=1]
ret i32 %C
}
declare void @foo2(i32)
;; It is ok and desirable to hoist this potentially trapping instruction.
define i32 @test2(i1 %c) {
; CHECK: @test2
; CHECK-NEXT: load i32* @X
; CHECK-NEXT: %B = sdiv i32 4, %A
%A = load i32* @X ; <i32> [#uses=2]
br label %Loop
Loop:
;; Should have hoisted this div!
%B = sdiv i32 4, %A ; <i32> [#uses=2]
call void @foo2( i32 %B )
br i1 %c, label %Loop, label %Out
Out: ; preds = %Loop
%C = sub i32 %A, %B ; <i32> [#uses=1]
ret i32 %C
}
; This loop invariant instruction should be constant folded, not hoisted.
define i32 @test3(i1 %c) {
; CHECK: define i32 @test3
; CHECK: call void @foo2(i32 6)
%A = load i32* @X ; <i32> [#uses=2]
br label %Loop
Loop:
%B = add i32 4, 2 ; <i32> [#uses=2]
call void @foo2( i32 %B )
br i1 %c, label %Loop, label %Out
Out: ; preds = %Loop
%C = sub i32 %A, %B ; <i32> [#uses=1]
ret i32 %C
}
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