1; RUN: opt -S -unroll-runtime -loop-unroll < %s | FileCheck %s 2 3target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" 4 5;; Check that we don't emit expensive instructions to compute trip 6;; counts when unrolling loops. 7 8define i32 @test(i64 %v12, i8* %array, i64* %loc) { 9; CHECK-LABEL: @test( 10; CHECK-NOT: udiv 11entry: 12 %step = load i64, i64* %loc, !range !0 13 br label %loop 14 15loop: ; preds = %entry, %loop 16 %k.015 = phi i64 [ %v15, %loop ], [ %v12, %entry ] 17 %v14 = getelementptr inbounds i8, i8* %array, i64 %k.015 18 store i8 0, i8* %v14 19 %v15 = add nuw nsw i64 %k.015, %step 20 %v16 = icmp slt i64 %v15, 8193 21 br i1 %v16, label %loop, label %loopexit 22 23loopexit: ; preds = %loop 24 ret i32 0 25} 26 27;; Though SCEV for loop tripcount contains division, 28;; it shouldn't be considered expensive, since the division already 29;; exists in the code and we don't need to expand it once more. 30;; Thus, it shouldn't prevent us from unrolling the loop. 31 32define i32 @test2(i64* %loc, i64 %conv7) { 33; CHECK-LABEL: @test2( 34; CHECK: udiv 35; CHECK: udiv 36; CHECK-NOT: udiv 37; CHECK-LABEL: for.body 38entry: 39 %rem0 = load i64, i64* %loc, align 8 40 %ExpensiveComputation = udiv i64 %rem0, 42 ; <<< Extra computations are added to the trip-count expression 41 br label %bb1 42bb1: 43 %div11 = udiv i64 %ExpensiveComputation, %conv7 44 %cmp.i38 = icmp ugt i64 %div11, 1 45 %div12 = select i1 %cmp.i38, i64 %div11, i64 1 46 br label %for.body 47for.body: 48 %rem1 = phi i64 [ %rem0, %bb1 ], [ %rem2, %for.body ] 49 %k1 = phi i64 [ %div12, %bb1 ], [ %dec, %for.body ] 50 %mul1 = mul i64 %rem1, 48271 51 %rem2 = urem i64 %mul1, 2147483647 52 %dec = add i64 %k1, -1 53 %cmp = icmp eq i64 %dec, 0 54 br i1 %cmp, label %exit, label %for.body 55exit: 56 %rem3 = phi i64 [ %rem2, %for.body ] 57 store i64 %rem3, i64* %loc, align 8 58 ret i32 0 59} 60 61!0 = !{i64 1, i64 100} 62