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Disable machine LICM speculation check (for profitability) until I have time to investigate the regressions.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141813 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2011-10-12 21:33:49 +00:00
parent 980df16920
commit 7007e4c556
1 changed files with 15 additions and 6 deletions
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21
lib/CodeGen/MachineLICM.cpp
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@ -37,10 +37,16 @@
#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h" #include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h" #include "llvm/ADT/Statistic.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h" #include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h" #include "llvm/Support/raw_ostream.h"
using namespace llvm; using namespace llvm;
static cl::opt<bool>
AvoidSpeculation("avoid-speculation",
cl::desc("MachineLICM should avoid speculation"),
cl::init(false), cl::Hidden);
STATISTIC(NumHoisted, STATISTIC(NumHoisted,
"Number of machine instructions hoisted out of loops"); "Number of machine instructions hoisted out of loops");
STATISTIC(NumLowRP, STATISTIC(NumLowRP,
@ -1052,14 +1058,17 @@ bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) {
return true; return true;
} }
// High register pressure situation, only hoist if the instruction is going to // Do not "speculate" in high register pressure situation. If an
// be remat'ed.
// Also, 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 // instruction is not guaranteed to be executed in the loop, it's best to be
// conservative. // conservative.
if ((!IsGuaranteedToExecute(MI.getParent()) && !MayCSE(&MI)) || if (AvoidSpeculation &&
(!TII->isTriviallyReMaterializable(&MI, AA) && (!IsGuaranteedToExecute(MI.getParent()) && !MayCSE(&MI)))
!MI.isInvariantLoad(AA))) 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; return false;
} }