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73f673d871
Current tail duplication in machine block placement pass uses block frequency information in cost model. But frequency number has only relative meaning compared to other basic blocks in the same function. A large frequency number doesn't mean it is hot and a small frequency number doesn't mean it is cold. To overcome this problem, this patch uses profile count in cost model if it's available. So we can tail duplicate real hot basic blocks. Differential Revision: https://reviews.llvm.org/D83265
106 lines
2.3 KiB
LLVM
106 lines
2.3 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
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; Cold function, %dup should not be duplicated into predecessors.
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define i32 @cold(i32 %a, i32* %p, i32* %q) !prof !21 {
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; CHECK-LABEL: cold
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; CHECK: %entry
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; CHECK: %true1
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; CHECK: %dup
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; CHECK: %true2
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; CHECK: %false1
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; CHECK: %false2
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entry:
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%cond1 = icmp sgt i32 %a, 1
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br i1 %cond1, label %true1, label %false1, !prof !30
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true1:
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%v1 = load i32, i32* %p, align 4
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%v2 = add i32 %v1, 2
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br label %dup
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false1:
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%v3 = load i32, i32* %q, align 4
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%v4 = sub i32 %v3, 3
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br label %dup
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dup:
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%v5 = phi i32 [%v2, %true1], [%v4, %false1]
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%cond2 = icmp sgt i32 %v5, 4
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br i1 %cond2, label %true2, label %false2, !prof !30
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true2:
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%v6 = xor i32 %v5, %a
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br label %exit
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false2:
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%v7 = and i32 %v5, %a
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br label %exit
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exit:
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%v8 = phi i32 [%v6, %true2], [%v7, %false2]
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ret i32 %v8
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}
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; Same code as previous function, but with hot profile count.
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; So %dup should be duplicated into predecessors.
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define i32 @hot(i32 %a, i32* %p, i32* %q) !prof !22 {
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; CHECK-LABEL: hot
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; CHECK: %entry
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; CHECK: %true1
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; CHECK: %false2
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; CHECK: %false1
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; CHECK: %true2
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entry:
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%cond1 = icmp sgt i32 %a, 1
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br i1 %cond1, label %true1, label %false1, !prof !30
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true1:
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%v1 = load i32, i32* %p, align 4
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%v2 = add i32 %v1, 2
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br label %dup
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false1:
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%v3 = load i32, i32* %q, align 4
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%v4 = sub i32 %v3, 3
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br label %dup
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dup:
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%v5 = phi i32 [%v2, %true1], [%v4, %false1]
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%cond2 = icmp sgt i32 %v5, 4
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br i1 %cond2, label %true2, label %false2, !prof !30
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true2:
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%v6 = xor i32 %v5, %a
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br label %exit
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false2:
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%v7 = and i32 %v5, %a
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br label %exit
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exit:
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%v8 = phi i32 [%v6, %true2], [%v7, %false2]
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ret i32 %v8
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}
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!llvm.module.flags = !{!1}
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!21 = !{!"function_entry_count", i64 10}
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!22 = !{!"function_entry_count", i64 400}
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!30 = !{!"branch_weights", i32 1, i32 1}
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!1 = !{i32 1, !"ProfileSummary", !2}
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!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
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!3 = !{!"ProfileFormat", !"InstrProf"}
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!4 = !{!"TotalCount", i64 10000}
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!5 = !{!"MaxCount", i64 10}
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!6 = !{!"MaxInternalCount", i64 1}
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!7 = !{!"MaxFunctionCount", i64 1000}
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!8 = !{!"NumCounts", i64 3}
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!9 = !{!"NumFunctions", i64 3}
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!10 = !{!"DetailedSummary", !11}
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!11 = !{!12, !13, !14}
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!12 = !{i32 10000, i64 100, i32 1}
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!13 = !{i32 999000, i64 100, i32 1}
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!14 = !{i32 999999, i64 1, i32 2}
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