Enable hoisting load from constant memories.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89510 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index 3f9ee48..66de535 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -34,16 +34,11 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/ADT/DenseMap.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> HoistLdConst("licm-const-load",
- cl::desc("LICM load from constant memory"),
- cl::init(false), cl::Hidden);
-
STATISTIC(NumHoisted, "Number of machine instructions hoisted out of loops");
STATISTIC(NumCSEed, "Number of hoisted machine instructions CSEed");
@@ -102,7 +97,7 @@
/// IsProfitableToHoist - Return true if it is potentially profitable to
/// hoist the given loop invariant.
- bool IsProfitableToHoist(MachineInstr &MI, bool &isConstLd);
+ bool IsProfitableToHoist(MachineInstr &MI);
/// HoistRegion - Walk the specified region of the CFG (defined by all
/// blocks dominated by the specified block, and that are in the current
@@ -367,9 +362,7 @@
/// IsProfitableToHoist - Return true if it is potentially profitable to hoist
/// the given loop invariant.
-bool MachineLICM::IsProfitableToHoist(MachineInstr &MI, bool &isConstLd) {
- isConstLd = false;
-
+bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) {
if (MI.getOpcode() == TargetInstrInfo::IMPLICIT_DEF)
return false;
@@ -382,9 +375,8 @@
// adding a store in the loop preheader. But the reload is no more expensive.
// The side benefit is these loads are frequently CSE'ed.
if (!TII->isTriviallyReMaterializable(&MI, AA)) {
- if (!HoistLdConst || !isLoadFromConstantMemory(&MI))
+ if (!isLoadFromConstantMemory(&MI))
return false;
- isConstLd = true;
}
// If result(s) of this instruction is used by PHIs, then don't hoist it.
@@ -439,9 +431,7 @@
MBB->insert(MI, NewMIs[1]);
// If unfolding produced a load that wasn't loop-invariant or profitable to
// hoist, discard the new instructions and bail.
- bool isConstLd;
- if (!IsLoopInvariantInst(*NewMIs[0]) ||
- !IsProfitableToHoist(*NewMIs[0], isConstLd)) {
+ if (!IsLoopInvariantInst(*NewMIs[0]) || !IsProfitableToHoist(*NewMIs[0])) {
NewMIs[0]->eraseFromParent();
NewMIs[1]->eraseFromParent();
return 0;
@@ -507,9 +497,7 @@
///
void MachineLICM::Hoist(MachineInstr *MI) {
// First check whether we should hoist this instruction.
- bool isConstLd;
- if (!IsLoopInvariantInst(*MI) ||
- !IsProfitableToHoist(*MI, isConstLd)) {
+ if (!IsLoopInvariantInst(*MI) || !IsProfitableToHoist(*MI)) {
// If not, try unfolding a hoistable load.
MI = ExtractHoistableLoad(MI);
if (!MI) return;
@@ -518,10 +506,7 @@
// Now move the instructions to the predecessor, inserting it before any
// terminator instructions.
DEBUG({
- errs() << "Hoisting ";
- if (isConstLd)
- errs() << "load from constant mem ";
- errs() << *MI;
+ errs() << "Hoisting " << *MI;
if (CurPreheader->getBasicBlock())
errs() << " to MachineBasicBlock "
<< CurPreheader->getName();