Commit c000b8bd authored by Wenlei He's avatar Wenlei He
Browse files

[CSSPGO] Use preinliner decision by default when available 

For CSSPGO, turn on `sample-profile-use-preinliner` by default. This simplifies the use of llvm-profgen preinliner as it's now simply driven by ContextShouldBeInlined flag for each context profile without needing extra compiler switch.

Note that llvm-profgen's preinliner is still off by default, under switch `csspgo-preinliner`.

Differential Revision: https://reviews.llvm.org/D109111
parent 2413d606

llvm/lib/Transforms/IPO/SampleProfile.cpp

+10 −7
Original line number Diff line number Diff line
@@ -1297,13 +1297,12 @@ SampleProfileLoader::shouldInlineCandidate(InlineCandidate &Candidate) { 
  // aiming at better context-sensitive post-inline profile quality, assuming

  // all inline decision estimates are going to be honored by compiler. Here

  // we replay that inline decision under `sample-profile-use-preinliner`.

  if (UsePreInlinerDecision) {

    if (Candidate.CalleeSamples->getContext().hasAttribute(

  // 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");

    else

      return InlineCost::getNever("preinliner");

  }



  // For old FDO inliner, we inline the call site as long as cost is not

  // "Never". The cost-benefit check is done earlier.
@@ -1827,6 +1826,10 @@ bool SampleProfileLoader::doInitialization(Module &M, 
    if (!CallsitePrioritizedInline.getNumOccurrences())

      CallsitePrioritizedInline = true;



    // For CSSPGO, use preinliner decision by default when available.

    if (!UsePreInlinerDecision.getNumOccurrences())

      UsePreInlinerDecision = true;



    // Enable iterative-BFI by default for CSSPGO.

    if (!UseIterativeBFIInference.getNumOccurrences())

      UseIterativeBFIInference = true;

llvm/test/Transforms/SampleProfile/csspgo-use-preinliner.ll

+2 −1
Original line number Diff line number Diff line
@@ -8,8 +8,9 @@ 
; DEFAULT-NOT: inlined into



; PREINLINE-NOT: inlined into

; PREINLINE: '_Z5funcAi' inlined into 'main'

; PREINLINE: '_Z8funcLeafi' inlined into 'main'

; PREINLINE: '_Z8funcLeafi' inlined into '_Z5funcBi'

; PREINLINE: '_Z8funcLeafi' inlined into '_Z5funcAi'

; PREINLINE-NOT: inlined into



@factor = dso_local global i32 3, align 4, !dbg !0