From 7007e4c5564f32fe4f06765a9740218039e7b492 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 12 Oct 2011 21:33:49 +0000 Subject: [PATCH] Disable machine LICM speculation check (for profitability) until I have time to investigate the regressions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141813 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineLICM.cpp | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp index 889406a4869..25109abae27 100644 --- a/lib/CodeGen/MachineLICM.cpp +++ b/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 +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; }