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9e1b62af44
This adds the following to the new PM based inliner in PGO mode: * Use block frequency analysis to derive callsite's profile count and use that to adjust thresholds of hot and cold callsites. * Incrementally update the BFI of the caller after a callee gets inlined into it. This incremental update is only within an invocation of the run method - BFI is not preserved across calls to run. Update the function entry count of the callee after inlining it into a caller. * I've tuned the thresholds for the hot and cold callsites using a hacked up version of the old inliner that explicitly computes BFI on a set of internal benchmarks and spec. Once the new PM based pipeline stabilizes (IIRC Chandler mentioned there are known issues) I'll benchmark this again and adjust the thresholds if required. Inliner PGO support. Differential revision: https://reviews.llvm.org/D28331 llvm-svn: 292666
51 lines
1.6 KiB
LLVM
51 lines
1.6 KiB
LLVM
; RUN: opt < %s -passes='require<profile-summary>,cgscc(inline)' -S | FileCheck %s
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; This tests that the function count of two callees get correctly updated after
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; they have been inlined into two back-to-back callsites in a single basic block
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; in the caller. The callees have the alwaysinline attribute and so they get
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; inlined both with the regular inliner pass and the always inline pass. In
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; both cases, the new count of each callee is the original count minus callsite
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; count which is 200 (since the caller's entry count is 400 and the block
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; containing the calls have a relative block frequency of 0.5).
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; CHECK: @callee1(i32 %n) #0 !prof [[COUNT1:![0-9]+]]
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define i32 @callee1(i32 %n) #0 !prof !1 {
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%cond = icmp sle i32 %n, 10
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br i1 %cond, label %cond_true, label %cond_false
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cond_true:
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%r1 = add i32 %n, 1
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ret i32 %r1
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cond_false:
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%r2 = add i32 %n, 2
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ret i32 %r2
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}
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; CHECK: @callee2(i32 %n) #0 !prof [[COUNT2:![0-9]+]]
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define i32 @callee2(i32 %n) #0 !prof !2 {
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%r1 = add i32 %n, 1
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ret i32 %r1
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}
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define i32 @caller(i32 %n) !prof !3 {
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%cond = icmp sle i32 %n, 100
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br i1 %cond, label %cond_true, label %cond_false
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cond_true:
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%i = call i32 @callee1(i32 %n)
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%j = call i32 @callee2(i32 %i)
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ret i32 %j
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cond_false:
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ret i32 0
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}
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!llvm.module.flags = !{!0}
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; CHECK: [[COUNT1]] = !{!"function_entry_count", i64 800}
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; CHECK: [[COUNT2]] = !{!"function_entry_count", i64 1800}
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!0 = !{i32 1, !"MaxFunctionCount", i32 1000}
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!1 = !{!"function_entry_count", i64 1000}
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!2 = !{!"function_entry_count", i64 2000}
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!3 = !{!"function_entry_count", i64 400}
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attributes #0 = { alwaysinline }
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