| ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2 |
| ; RUN: opt < %s -passes='print<scalar-evolution>,simple-loop-unswitch<no-nontrivial>,print<scalar-evolution>' -disable-output 2>&1 | FileCheck -check-prefix CHECK-SCEV %s |
| ; RUN: opt < %s -passes='function(loop-deletion,simple-loop-unswitch<no-nontrivial>),verify<scalar-evolution>' -S | FileCheck -check-prefix CHECK-IR %s |
| |
| ; These tests used to hit an assertion failure in llvm::ScalarEvolution::BackedgeTakenInfo::getExact: |
| ; "We should only have known counts for exiting blocks that dominate latch!"' failed. |
| ; |
| ; Verify that we no longer hit that assert, while we expect to have forgotten SCEV for the outer loop. |
| ; Also added checks to show and verify the IR transformation. |
| |
| |
| ; Before the unswitch: |
| ; |
| ; CHECK-SCEV: Classifying expressions for: @f4 |
| ; CHECK-SCEV-NEXT: %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ] |
| ; CHECK-SCEV-NEXT: --> {0,+,1}<nuw><nsw><%lbl1> U: [0,3) S: [0,3) Exits: 2 LoopDispositions: { %lbl1: Computable, %lbl2: Invariant } |
| ; CHECK-SCEV-NEXT: %0 = add i16 %j.0, 1 |
| ; CHECK-SCEV-NEXT: --> {1,+,1}<nuw><nsw><%lbl1> U: [1,4) S: [1,4) Exits: 3 LoopDispositions: { %lbl1: Computable, %lbl2: Invariant } |
| ; CHECK-SCEV-DAG: Loop %lbl2: Unpredictable backedge-taken count. |
| ; CHECK-SCEV-DAG: Loop %lbl1: backedge-taken count is i16 2 |
| ; |
| ; After the unswitch: |
| ; |
| ; CHECK-SCEV: Classifying expressions for: @f4 |
| ; CHECK-SCEV-NEXT: %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ] |
| ; CHECK-SCEV-NEXT: --> {0,+,1}<nuw><nsw><%lbl1> U: [0,-32768) S: [0,-32768) Exits: <<Unknown>> LoopDispositions: { %lbl1: Computable } |
| ; CHECK-SCEV-NEXT: %0 = add i16 %j.0, 1 |
| ; CHECK-SCEV-NEXT: --> {1,+,1}<nuw><nsw><%lbl1> U: [1,-32768) S: [1,-32768) Exits: <<Unknown>> LoopDispositions: { %lbl1: Computable } |
| ; CHECK-SCEV-DAG: Loop %lbl1: Unpredictable backedge-taken count. |
| ; CHECK-SCEV-DAG: Loop %lbl2: <multiple exits> Unpredictable backedge-taken count. |
| |
| |
| define i16 @f4() { |
| ; CHECK-IR-LABEL: define i16 @f4() { |
| ; CHECK-IR-NEXT: entry: |
| ; CHECK-IR-NEXT: br label [[LBL1:%.*]] |
| ; CHECK-IR: lbl1: |
| ; CHECK-IR-NEXT: [[J_0:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[TMP0:%.*]], [[SW_BB2:%.*]] ] |
| ; CHECK-IR-NEXT: switch i16 [[J_0]], label [[LBL1_SPLIT:%.*]] [ |
| ; CHECK-IR-NEXT: i16 0, label [[SW_BB2]] |
| ; CHECK-IR-NEXT: i16 1, label [[SW_BB2]] |
| ; CHECK-IR-NEXT: i16 2, label [[LBL3:%.*]] |
| ; CHECK-IR-NEXT: ] |
| ; CHECK-IR: lbl1.split: |
| ; CHECK-IR-NEXT: br label [[LBL2:%.*]] |
| ; CHECK-IR: lbl2: |
| ; CHECK-IR-NEXT: br label [[LBL2]] |
| ; CHECK-IR: sw.bb2: |
| ; CHECK-IR-NEXT: [[TMP0]] = add i16 [[J_0]], 1 |
| ; CHECK-IR-NEXT: br label [[LBL1]] |
| ; CHECK-IR: lbl3: |
| ; CHECK-IR-NEXT: ret i16 0 |
| ; |
| entry: |
| br label %lbl1 |
| |
| lbl1: ; preds = %sw.bb2, %entry |
| %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ] |
| br label %lbl2 |
| |
| lbl2: ; preds = %lbl2, %lbl1 |
| switch i16 %j.0, label %lbl2 [ |
| i16 0, label %sw.bb2 |
| i16 1, label %sw.bb2 |
| i16 2, label %lbl3 |
| ] |
| |
| sw.bb2: ; preds = %lbl2, %lbl2 |
| %0 = add i16 %j.0, 1 |
| br label %lbl1 |
| |
| lbl3: ; preds = %lbl2 |
| ret i16 0 |
| } |
| |