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