diff --git a/llvm/lib/Transforms/IPO/SampleContextTracker.cpp b/llvm/lib/Transforms/IPO/SampleContextTracker.cpp --- a/llvm/lib/Transforms/IPO/SampleContextTracker.cpp +++ b/llvm/lib/Transforms/IPO/SampleContextTracker.cpp @@ -545,6 +545,8 @@ ToSamples->merge(*FromSamples); ToSamples->getContext().setState(SyntheticContext); FromSamples->getContext().setState(MergedContext); + if (FromSamples->getContext().hasAttribute(ContextShouldBeInlined)) + ToSamples->getContext().setAttribute(ContextShouldBeInlined); } else if (FromSamples) { // Transfer FromSamples from FromNode to ToNode ToNode.setFunctionSamples(FromSamples); diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp --- a/llvm/lib/Transforms/IPO/SampleProfile.cpp +++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp @@ -977,7 +977,14 @@ // For CSSPGO profile, retrieve candidate profile by walking over the // trie built for context profile. Note that also take call targets // even if callee doesn't have a corresponding context profile. - if (!CalleeSample || CalleeSample->getEntrySamples() < Threshold) + if (!CalleeSample) + continue; + + // If pre-inliner decision is used, honor that for importing as well. + bool PreInline = + UsePreInlinerDecision && + CalleeSample->getContext().hasAttribute(ContextShouldBeInlined); + if (!PreInline && CalleeSample->getEntrySamples() < Threshold) continue; StringRef Name = CalleeSample->getFuncName(); @@ -1299,10 +1306,13 @@ // we replay that inline decision under `sample-profile-use-preinliner`. // Note that we don't need to handle negative decision from preinliner as // context profile for not inlined calls are merged by preinliner already. - if (UsePreInlinerDecision && - Candidate.CalleeSamples->getContext().hasAttribute( - ContextShouldBeInlined)) - return InlineCost::getAlways("preinliner"); + SampleContext &Context = Candidate.CalleeSamples->getContext(); + if (UsePreInlinerDecision && Context.hasAttribute(ContextShouldBeInlined)) + // Once two node are merged due to promotion, we're losing some context + // so the original context-sensitive preinliner decision should be ignored + // for SyntheticContext. + if (!Context.hasState(SyntheticContext)) + return InlineCost::getAlways("preinliner"); // For old FDO inliner, we inline the call site as long as cost is not // "Never". The cost-benefit check is done earlier. diff --git a/llvm/test/Transforms/SampleProfile/csspgo-use-preinliner.ll b/llvm/test/Transforms/SampleProfile/csspgo-use-preinliner.ll --- a/llvm/test/Transforms/SampleProfile/csspgo-use-preinliner.ll +++ b/llvm/test/Transforms/SampleProfile/csspgo-use-preinliner.ll @@ -8,9 +8,12 @@ ; DEFAULT-NOT: inlined into ; PREINLINE-NOT: inlined into +; `[main:3 @ _Z5funcAi]` does not have preinline decision, so it's up for loader inliner to decided. ; PREINLINE: '_Z5funcAi' inlined into 'main' +; `[main:3 @ _Z5funcAi:1 @ _Z8funcLeafi]` is inlined according to preinline decision. ; PREINLINE: '_Z8funcLeafi' inlined into 'main' -; PREINLINE: '_Z8funcLeafi' inlined into '_Z5funcBi' +; Even though `[main:3.1 @ _Z5funcBi]` context is marked should inline, `_Z5funcBi` is a noinline function, so we honor that and don't inline. +; When _Z5funcBi is promoted to be top level context-less profile, `[_Z5funcBi:1 @ _Z8funcLeafi]` becomes synthetic context, so preinline decision is ignored and we don't inline `_Z8funcLeafi`. ; PREINLINE-NOT: inlined into @factor = dso_local global i32 3, align 4, !dbg !0