1; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py 2; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s 3 4target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 5target triple = "x86_64-unknown-linux-gnu" 6 7; Previously in this case the max backedge count would be computed as 1/0, which 8; is correct but undesirable. It would also not fold as a constant, tripping 9; asserts in SCEV. 10 11define void @pluto(i32 %arg) { 12; CHECK-LABEL: 'pluto' 13; CHECK-NEXT: Classifying expressions for: @pluto 14; CHECK-NEXT: %tmp = ashr i32 %arg, 31 15; CHECK-NEXT: --> %tmp U: [-1,1) S: [-1,1) 16; CHECK-NEXT: %tmp1 = add nsw i32 %tmp, 2 17; CHECK-NEXT: --> (2 + %tmp)<nsw> U: [1,3) S: [1,3) 18; CHECK-NEXT: %tmp3 = phi i32 [ 0, %bb ], [ %tmp4, %bb2 ] 19; CHECK-NEXT: --> {0,+,(2 + %tmp)<nsw>}<nuw><nsw><%bb2> U: [0,3) S: [0,3) Exits: ((2 + %tmp)<nsw> * (1 /u (2 + %tmp)<nsw>))<nuw> LoopDispositions: { %bb2: Computable } 20; CHECK-NEXT: %tmp4 = add nuw nsw i32 %tmp1, %tmp3 21; CHECK-NEXT: --> {(2 + %tmp)<nsw>,+,(2 + %tmp)<nsw>}<nuw><nsw><%bb2> U: [1,5) S: [1,5) Exits: (2 + ((2 + %tmp)<nsw> * (1 /u (2 + %tmp)<nsw>))<nuw> + %tmp) LoopDispositions: { %bb2: Computable } 22; CHECK-NEXT: Determining loop execution counts for: @pluto 23; CHECK-NEXT: Loop %bb2: backedge-taken count is (1 /u (2 + %tmp)<nsw>) 24; CHECK-NEXT: Loop %bb2: constant max backedge-taken count is i32 1 25; CHECK-NEXT: Loop %bb2: symbolic max backedge-taken count is (1 /u (2 + %tmp)<nsw>) 26; CHECK-NEXT: Loop %bb2: Trip multiple is 1 27; 28bb: 29 %tmp = ashr i32 %arg, 31 30 %tmp1 = add nsw i32 %tmp, 2 31 br label %bb2 32 33bb2: ; preds = %bb2, %bb 34 %tmp3 = phi i32 [ 0, %bb ], [ %tmp4, %bb2 ] 35 %tmp4 = add nuw nsw i32 %tmp1, %tmp3 36 %tmp5 = icmp ult i32 %tmp4, 2 37 br i1 %tmp5, label %bb2, label %bb6 38 39bb6: ; preds = %bb2 40 ret void 41} 42