| ; 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 |
| } |