; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" ; Previously in this case the max backedge count would be computed as 1/0, which ; is correct but undesirable. It would also not fold as a constant, tripping ; asserts in SCEV. define void @pluto(i32 %arg) { ; CHECK-LABEL: 'pluto' ; CHECK-NEXT: Classifying expressions for: @pluto ; CHECK-NEXT: %tmp = ashr i32 %arg, 31 ; CHECK-NEXT: --> %tmp U: [-1,1) S: [-1,1) ; CHECK-NEXT: %tmp1 = add nsw i32 %tmp, 2 ; CHECK-NEXT: --> (2 + %tmp)<nsw> U: [1,3) S: [1,3) ; CHECK-NEXT: %tmp3 = phi i32 [ 0, %bb ], [ %tmp4, %bb2 ] ; 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 } ; CHECK-NEXT: %tmp4 = add nuw nsw i32 %tmp1, %tmp3 ; 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 } ; CHECK-NEXT: Determining loop execution counts for: @pluto ; CHECK-NEXT: Loop %bb2: backedge-taken count is (1 /u (2 + %tmp)<nsw>) ; CHECK-NEXT: Loop %bb2: max backedge-taken count is 1 ; CHECK-NEXT: Loop %bb2: Predicated backedge-taken count is (1 /u (2 + %tmp)<nsw>) ; CHECK-NEXT: Predicates: ; CHECK: Loop %bb2: Trip multiple is 1 ; bb: %tmp = ashr i32 %arg, 31 %tmp1 = add nsw i32 %tmp, 2 br label %bb2 bb2: ; preds = %bb2, %bb %tmp3 = phi i32 [ 0, %bb ], [ %tmp4, %bb2 ] %tmp4 = add nuw nsw i32 %tmp1, %tmp3 %tmp5 = icmp ult i32 %tmp4, 2 br i1 %tmp5, label %bb2, label %bb6 bb6: ; preds = %bb2 ret void }