1; RUN: llc -O3 -o - %s | FileCheck %s 2target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 3target triple = "x86_64-unknown-linux-gnu" 4 5declare void @effect(i32); 6 7; After the loop gets laid out, loop.end is the only successor, but can't be 8; laid out because of the CFG dependency from top.fakephi. The calculations show 9; that it isn't profitable to tail-duplicate in this case, because of the 10; effects on fallthrough from %loop.end 11; CHECK-LABEL: {{^}}no_successor_still_no_taildup: 12; CHECK: %entry 13; CHECK: %loop.top 14; CHECK: %loop.latch 15; CHECK: %top.fakephi 16; CHECK: %loop.end 17; CHECK: %false 18; CHECK: %ret 19define void @no_successor_still_no_taildup (i32 %count, i32 %key) { 20entry: 21 br label %loop.top 22 23loop.top: 24 %i.loop.top = phi i32 [ %count, %entry ], [ %i.latch, %loop.latch ] 25 %cmp.top = icmp eq i32 %i.loop.top, %key 26 call void @effect(i32 0) 27 br i1 %cmp.top, label %top.fakephi, label %loop.latch, !prof !1 28 29loop.latch: 30 %i.latch = sub i32 %i.loop.top, 1 31 %cmp.latch = icmp eq i32 %i.latch, 0 32 call void @effect(i32 1) 33 br i1 %cmp.top, label %loop.top, label %loop.end, !prof !2 34 35top.fakephi: 36 call void @effect(i32 2) 37 br label %loop.end 38 39loop.end: 40 %cmp.end = icmp eq i32 %count, 0 41 br i1 %cmp.end, label %ret, label %false, !prof !3 42 43false: 44 call void @effect(i32 4) 45 br label %ret 46 47ret: 48 ret void 49} 50 51!1 = !{!"branch_weights", i32 1, i32 1} 52!2 = !{!"branch_weights", i32 5, i32 1} 53!3 = !{!"branch_weights", i32 1, i32 2} 54