1 ; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s 2 3 ; ScalarEvolution should be able to compute trip count of the loop by proving 4 ; that this is not an infinite loop with side effects. 5 6 ; CHECK: Determining loop execution counts for: @foo1 7 ; CHECK: backedge-taken count is ((-1 + %n) /u %s) 8 9 ; We should have a conservative estimate for the max backedge taken count for 10 ; loops with unknown stride. 11 ; CHECK: max backedge-taken count is -1 12 13 target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128" 14 15 ; Function Attrs: norecurse nounwind 16 define void @foo1(i32* nocapture %A, i32 %n, i32 %s) #0 { 17 entry: 18 %cmp4 = icmp sgt i32 %n, 0 19 br i1 %cmp4, label %for.body, label %for.end 20 21 for.body: ; preds = %entry, %for.body 22 %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ] 23 %arrayidx = getelementptr inbounds i32, i32* %A, i32 %i.05 24 %0 = load i32, i32* %arrayidx, align 4 25 %inc = add nsw i32 %0, 1 26 store i32 %inc, i32* %arrayidx, align 4 27 %add = add nsw i32 %i.05, %s 28 %cmp = icmp slt i32 %add, %n 29 br i1 %cmp, label %for.body, label %for.end 30 31 for.end: ; preds = %for.body, %entry 32 ret void 33 } 34 35 36 ; Check that we are able to compute trip count of a loop without an entry guard. 37 ; CHECK: Determining loop execution counts for: @foo2 38 ; CHECK: backedge-taken count is ((-1 + (%n smax %s)) /u %s) 39 40 ; We should have a conservative estimate for the max backedge taken count for 41 ; loops with unknown stride. 42 ; CHECK: max backedge-taken count is -1 43 44 ; Function Attrs: norecurse nounwind 45 define void @foo2(i32* nocapture %A, i32 %n, i32 %s) #0 { 46 entry: 47 br label %for.body 48 49 for.body: ; preds = %entry, %for.body 50 %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ] 51 %arrayidx = getelementptr inbounds i32, i32* %A, i32 %i.05 52 %0 = load i32, i32* %arrayidx, align 4 53 %inc = add nsw i32 %0, 1 54 store i32 %inc, i32* %arrayidx, align 4 55 %add = add nsw i32 %i.05, %s 56 %cmp = icmp slt i32 %add, %n 57 br i1 %cmp, label %for.body, label %for.end 58 59 for.end: ; preds = %for.body, %entry 60 ret void 61 } 62 63
