diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineFunctionSplitter.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineFunctionSplitter.cpp | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp index 1a1bd901..b2f474a 100644 --- a/llvm/lib/CodeGen/MachineFunctionSplitter.cpp +++ b/llvm/lib/CodeGen/MachineFunctionSplitter.cpp @@ -39,11 +39,18 @@ using namespace llvm; +// FIXME: This cutoff value is CPU dependent and should be moved to +// TargetTransformInfo once we consider enabling this on other platforms. +// The value is expressed as a ProfileSummaryInfo integer percentile cutoff. +// Defaults to 999950, i.e. all blocks colder than 99.995 percentile are split. +// The default was empirically determined to be optimal when considering cutoff +// values between 99%-ile to 100%-ile with respect to iTLB and icache metrics on +// Intel CPUs. static cl::opt<unsigned> PercentileCutoff("mfs-psi-cutoff", cl::desc("Percentile profile summary cutoff used to " "determine cold blocks. Unused if set to zero."), - cl::init(0), cl::Hidden); + cl::init(999950), cl::Hidden); static cl::opt<unsigned> ColdCountThreshold( "mfs-count-threshold", |