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[Inliner] Do not mix callsite and callee hotness based updates.

Update threshold based on callee's hotness only when BFI is not available.
Otherwise use only callsite's hotness. This makes it easier to reason about
hotness related threshold updates.

Differential revision: https://reviews.llvm.org/D33157

llvm-svn: 303210
This commit is contained in:
Easwaran Raman 2017-05-16 21:18:09 +00:00
parent 82dcf06a2b
commit d91313ddb5
2 changed files with 32 additions and 20 deletions

View File

@ -669,21 +669,33 @@ void CallAnalyzer::updateThreshold(CallSite CS, Function &Callee) {
Threshold = MaxIfValid(Threshold, Params.HintThreshold); Threshold = MaxIfValid(Threshold, Params.HintThreshold);
if (PSI) { if (PSI) {
BlockFrequencyInfo *CallerBFI = GetBFI ? &((*GetBFI)(*Caller)) : nullptr; BlockFrequencyInfo *CallerBFI = GetBFI ? &((*GetBFI)(*Caller)) : nullptr;
if (PSI->isHotCallSite(CS, CallerBFI)) { // FIXME: After switching to the new passmanager, simplify the logic below
DEBUG(dbgs() << "Hot callsite.\n"); // by checking only the callsite hotness/coldness. The check for CallerBFI
Threshold = Params.HotCallSiteThreshold.getValue(); // exists only because we do not have BFI available with the old PM.
} else if (PSI->isFunctionEntryHot(&Callee)) { //
DEBUG(dbgs() << "Hot callee.\n"); // Use callee's hotness information only if we have no way of determining
// If callsite hotness can not be determined, we may still know // callsite's hotness information. Callsite hotness can be determined if
// that the callee is hot and treat it as a weaker hint for threshold // sample profile is used (which adds hotness metadata to calls) or if
// increase. // caller's BlockFrequencyInfo is available.
Threshold = MaxIfValid(Threshold, Params.HintThreshold); if (CallerBFI || PSI->hasSampleProfile()) {
} else if (PSI->isColdCallSite(CS, CallerBFI)) { if (PSI->isHotCallSite(CS, CallerBFI)) {
DEBUG(dbgs() << "Cold callsite.\n"); DEBUG(dbgs() << "Hot callsite.\n");
Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold); Threshold = Params.HotCallSiteThreshold.getValue();
} else if (PSI->isFunctionEntryCold(&Callee)) { } else if (PSI->isColdCallSite(CS, CallerBFI)) {
DEBUG(dbgs() << "Cold callee.\n"); DEBUG(dbgs() << "Cold callsite.\n");
Threshold = MinIfValid(Threshold, Params.ColdThreshold); Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold);
}
} else {
if (PSI->isFunctionEntryHot(&Callee)) {
DEBUG(dbgs() << "Hot callee.\n");
// If callsite hotness can not be determined, we may still know
// that the callee is hot and treat it as a weaker hint for threshold
// increase.
Threshold = MaxIfValid(Threshold, Params.HintThreshold);
} else if (PSI->isFunctionEntryCold(&Callee)) {
DEBUG(dbgs() << "Cold callee.\n");
Threshold = MinIfValid(Threshold, Params.ColdThreshold);
}
} }
} }
} }

View File

@ -1,10 +1,10 @@
; RUN: opt < %s -inline -inline-threshold=0 -inlinehint-threshold=100 -S | FileCheck %s ; RUN: opt < %s -inline -inline-threshold=0 -inlinehint-threshold=100 -S | FileCheck %s
; RUN: opt < %s -passes='require<profile-summary>,cgscc(inline)' -inline-threshold=0 -inlinehint-threshold=100 -S | FileCheck %s
; This tests that a hot callee gets the (higher) inlinehint-threshold even without ; This tests that a hot callee gets the (higher) inlinehint-threshold even
; inline hints and gets inlined because the cost is less than inlinehint-threshold. ; without inline hints and gets inlined because the cost is less than
; A cold callee with identical body does not get inlined because cost exceeds the ; inlinehint-threshold. A cold callee with identical body does not get inlined
; inline-threshold ; because cost exceeds the inline-threshold. This test is relevant only when the
; old pass manager is used.
define i32 @callee1(i32 %x) !prof !21 { define i32 @callee1(i32 %x) !prof !21 {
%x1 = add i32 %x, 1 %x1 = add i32 %x, 1