diff --git a/llvm/test/Analysis/ScalarEvolution/implied-via-division.ll b/llvm/test/Analysis/ScalarEvolution/implied-via-division.ll index fbe69b4b18897..a1d30406095ec 100644 --- a/llvm/test/Analysis/ScalarEvolution/implied-via-division.ll +++ b/llvm/test/Analysis/ScalarEvolution/implied-via-division.ll @@ -411,3 +411,56 @@ header: exit: ret void } + +define void @swapped_predicate(i32 %n) { +; Prove that (n s>= 1) ===> (0 s>= -n / 2). +; CHECK-LABEL: 'swapped_predicate' +; CHECK-NEXT: Determining loop execution counts for: @swapped_predicate +; CHECK-NEXT: Loop %header: backedge-taken count is (1 + %n.div.2) +; CHECK-NEXT: Loop %header: constant max backedge-taken count is i32 1073741824 +; CHECK-NEXT: Loop %header: symbolic max backedge-taken count is (1 + %n.div.2) +; CHECK-NEXT: Loop %header: Trip multiple is 1 +; +entry: + %cmp1 = icmp sge i32 %n, 1 + %n.div.2 = sdiv i32 %n, 2 + call void @llvm.assume(i1 %cmp1) + br label %header + +header: + %indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ] + %indvar.next = add i32 %indvar, 1 + %minus.indvar = sub nsw i32 0, %indvar + %minus.n.div.2 = sub nsw i32 0, %n.div.2 + %exitcond = icmp sge i32 %minus.indvar, %minus.n.div.2 + br i1 %exitcond, label %header, label %exit + +exit: + ret void +} + +define void @swapped_predicate_neg(i32 %n) { +; Prove that (n s>= 1) =\=> (-n / 2 s>= 0). +; CHECK-LABEL: 'swapped_predicate_neg' +; CHECK-NEXT: Determining loop execution counts for: @swapped_predicate_neg +; CHECK-NEXT: Loop %header: Unpredictable backedge-taken count. +; CHECK-NEXT: Loop %header: Unpredictable constant max backedge-taken count. +; CHECK-NEXT: Loop %header: Unpredictable symbolic max backedge-taken count. +; +entry: + %cmp1 = icmp sge i32 %n, 1 + %n.div.2 = sdiv i32 %n, 2 + call void @llvm.assume(i1 %cmp1) + br label %header + +header: + %indvar = phi i32 [ %indvar.next, %header ], [ 0, %entry ] + %indvar.next = add i32 %indvar, 1 + %minus.indvar = sub nsw i32 0, %indvar + %minus.n.div.2 = sub nsw i32 0, %n.div.2 + %exitcond = icmp sge i32 %minus.n.div.2, %minus.indvar + br i1 %exitcond, label %header, label %exit + +exit: + ret void +}