forked from OSchip/llvm-project
54 lines
1.4 KiB
LLVM
54 lines
1.4 KiB
LLVM
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; RUN: llc -O3 -o - %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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declare void @effect(i32);
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; After the loop gets laid out, loop.end is the only successor, but can't be
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; laid out because of the CFG dependency from top.fakephi. The calculations show
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; that it isn't profitable to tail-duplicate in this case, because of the
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; effects on fallthrough from %loop.end
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; CHECK-LABEL: {{^}}no_successor_still_no_taildup:
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; CHECK: %entry
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; CHECK: %loop.top
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; CHECK: %loop.latch
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; CHECK: %top.fakephi
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; CHECK: %loop.end
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; CHECK: %false
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; CHECK: %ret
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define void @no_successor_still_no_taildup (i32 %count, i32 %key) {
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entry:
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br label %loop.top
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loop.top:
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%i.loop.top = phi i32 [ %count, %entry ], [ %i.latch, %loop.latch ]
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%cmp.top = icmp eq i32 %i.loop.top, %key
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call void @effect(i32 0)
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br i1 %cmp.top, label %top.fakephi, label %loop.latch, !prof !1
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loop.latch:
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%i.latch = sub i32 %i.loop.top, 1
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%cmp.latch = icmp eq i32 %i.latch, 0
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call void @effect(i32 1)
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br i1 %cmp.top, label %loop.top, label %loop.end, !prof !2
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top.fakephi:
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call void @effect(i32 2)
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br label %loop.end
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loop.end:
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%cmp.end = icmp eq i32 %count, 0
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br i1 %cmp.end, label %ret, label %false, !prof !3
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false:
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call void @effect(i32 4)
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br label %ret
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ret:
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ret void
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}
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!1 = !{!"branch_weights", i32 1, i32 1}
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!2 = !{!"branch_weights", i32 5, i32 1}
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!3 = !{!"branch_weights", i32 1, i32 2}
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