diff options
| -rw-r--r-- | llvm/lib/CodeGen/MachineLICM.cpp | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/llvm/lib/CodeGen/MachineLICM.cpp b/llvm/lib/CodeGen/MachineLICM.cpp index 889406a4869..25109abae27 100644 --- a/llvm/lib/CodeGen/MachineLICM.cpp +++ b/llvm/lib/CodeGen/MachineLICM.cpp @@ -37,10 +37,16 @@ #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/SmallSet.h" #include "llvm/ADT/Statistic.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; +static cl::opt<bool> +AvoidSpeculation("avoid-speculation", + cl::desc("MachineLICM should avoid speculation"), + cl::init(false), cl::Hidden); + STATISTIC(NumHoisted, "Number of machine instructions hoisted out of loops"); STATISTIC(NumLowRP, @@ -1052,14 +1058,17 @@ bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) { return true; } - // High register pressure situation, only hoist if the instruction is going to - // be remat'ed. - // Also, do not "speculate" in high register pressure situation. If an + // Do not "speculate" in high register pressure situation. If an // instruction is not guaranteed to be executed in the loop, it's best to be // conservative. - if ((!IsGuaranteedToExecute(MI.getParent()) && !MayCSE(&MI)) || - (!TII->isTriviallyReMaterializable(&MI, AA) && - !MI.isInvariantLoad(AA))) + if (AvoidSpeculation && + (!IsGuaranteedToExecute(MI.getParent()) && !MayCSE(&MI))) + return false; + + // High register pressure situation, only hoist if the instruction is going to + // be remat'ed. + if (!TII->isTriviallyReMaterializable(&MI, AA) && + !MI.isInvariantLoad(AA)) return false; } |
