Replace TargetInstrInfo::isInvariantLoad and its target-specific
implementations with a new MachineInstr::isInvariantLoad, which uses
MachineMemOperands and is target-independent. This brings MachineLICM
and other functionality to targets which previously lacked an
isInvariantLoad implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83475 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/CodeGen/MachineInstr.h b/include/llvm/CodeGen/MachineInstr.h
index 66af73e..27265da 100644
--- a/include/llvm/CodeGen/MachineInstr.h
+++ b/include/llvm/CodeGen/MachineInstr.h
@@ -26,6 +26,7 @@
namespace llvm {
+class AliasAnalysis;
class TargetInstrDesc;
class TargetInstrInfo;
class TargetRegisterInfo;
@@ -286,6 +287,13 @@
/// have no volatile memory references.
bool hasVolatileMemoryRef() const;
+ /// isInvariantLoad - Return true if this instruction is loading from a
+ /// location whose value is invariant across the function. For example,
+ /// loading a value from the constant pool or from from the argument area of
+ /// a function if it does not change. This should only return true of *all*
+ /// loads the instruction does are invariant (if it does multiple loads).
+ bool isInvariantLoad(AliasAnalysis *AA = 0) const;
+
//
// Debugging support
//
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 2d21a9b..74a47c2 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -157,16 +157,6 @@
unsigned DestReg, unsigned SubIdx,
const MachineInstr *Orig) const = 0;
- /// isInvariantLoad - Return true if the specified instruction (which is
- /// marked mayLoad) is loading from a location whose value is invariant across
- /// the function. For example, loading a value from the constant pool or from
- /// from the argument area of a function if it does not change. This should
- /// only return true of *all* loads the instruction does are invariant (if it
- /// does multiple loads).
- virtual bool isInvariantLoad(const MachineInstr *MI) const {
- return false;
- }
-
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into one or more true
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index a3560a7..2dc99f5 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -24,6 +24,7 @@
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetInstrDesc.h"
#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LeakDetector.h"
@@ -946,7 +947,7 @@
// destination. The check for isInvariantLoad gives the targe the chance to
// classify the load as always returning a constant, e.g. a constant pool
// load.
- if (TID->mayLoad() && !TII->isInvariantLoad(this))
+ if (TID->mayLoad() && !isInvariantLoad())
// Otherwise, this is a real load. If there is a store between the load and
// end of block, or if the load is volatile, we can't move it.
return !SawStore && !hasVolatileMemoryRef();
@@ -1005,6 +1006,46 @@
return false;
}
+/// isInvariantLoad - Return true if this instruction is loading from a
+/// location whose value is invariant across the function. For example,
+/// loading a value from the constant pool or from from the argument area
+/// of a function if it does not change. This should only return true of
+/// *all* loads the instruction does are invariant (if it does multiple loads).
+bool MachineInstr::isInvariantLoad(AliasAnalysis *AA) const {
+ // If the instruction doesn't load at all, it isn't an invariant load.
+ if (!TID->mayLoad())
+ return false;
+
+ // If the instruction has lost its memoperands, conservatively assume that
+ // it may not be an invariant load.
+ if (memoperands_empty())
+ return false;
+
+ const MachineFrameInfo *MFI = getParent()->getParent()->getFrameInfo();
+
+ for (mmo_iterator I = memoperands_begin(),
+ E = memoperands_end(); I != E; ++I) {
+ if ((*I)->isVolatile()) return false;
+ if ((*I)->isStore()) return false;
+
+ if (const Value *V = (*I)->getValue()) {
+ // A load from a constant PseudoSourceValue is invariant.
+ if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V))
+ if (PSV->isConstant(MFI))
+ continue;
+ // If we have an AliasAnalysis, ask it whether the memory is constant.
+ if (AA && AA->pointsToConstantMemory(V))
+ continue;
+ }
+
+ // Otherwise assume conservatively.
+ return false;
+ }
+
+ // Everything checks out.
+ return true;
+}
+
void MachineInstr::dump() const {
errs() << " " << *this;
}
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index 61678f1..b5827aa 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -28,6 +28,7 @@
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
@@ -47,6 +48,7 @@
BitVector AllocatableSet;
// Various analyses that we use...
+ AliasAnalysis *AA; // Alias analysis info.
MachineLoopInfo *LI; // Current MachineLoopInfo
MachineDominatorTree *DT; // Machine dominator tree for the cur loop
MachineRegisterInfo *RegInfo; // Machine register information
@@ -72,6 +74,7 @@
AU.setPreservesCFG();
AU.addRequired<MachineLoopInfo>();
AU.addRequired<MachineDominatorTree>();
+ AU.addRequired<AliasAnalysis>();
AU.addPreserved<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
MachineFunctionPass::getAnalysisUsage(AU);
@@ -144,6 +147,7 @@
// Get our Loop information...
LI = &getAnalysis<MachineLoopInfo>();
DT = &getAnalysis<MachineDominatorTree>();
+ AA = &getAnalysis<AliasAnalysis>();
for (MachineLoopInfo::iterator
I = LI->begin(), E = LI->end(); I != E; ++I) {
@@ -214,7 +218,7 @@
// Okay, this instruction does a load. As a refinement, we allow the target
// to decide whether the loaded value is actually a constant. If so, we can
// actually use it as a load.
- if (!TII->isInvariantLoad(&I))
+ if (!I.isInvariantLoad(AA))
// FIXME: we should be able to sink loads with no other side effects if
// there is nothing that can change memory from here until the end of
// block. This is a trivial form of alias analysis.
@@ -259,8 +263,6 @@
// Don't hoist an instruction that uses or defines a physical register.
if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
- // If this is a physical register use, we can't move it. If it is a def,
- // we can move it, but only if the def is dead.
if (MO.isUse()) {
// If the physreg has no defs anywhere, it's just an ambient register
// and we can freely move its uses. Alternatively, if it's allocatable,
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 636dad8..e5c3420 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -178,8 +178,6 @@
if (Reg == 0) continue;
if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
- // If this is a physical register use, we can't move it. If it is a def,
- // we can move it, but only if the def is dead.
if (MO.isUse()) {
// If the physreg has no defs anywhere, it's just an ambient register
// and we can freely move its uses. Alternatively, if it's allocatable,
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp
index b55e606..f50844f 100644
--- a/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -375,7 +375,7 @@
// Treat all other stores conservatively.
goto new_chain;
} else if (TID.mayLoad()) {
- if (TII->isInvariantLoad(MI)) {
+ if (MI->isInvariantLoad()) {
// Invariant load, no chain dependencies needed!
} else if (const Value *V = getUnderlyingObjectForInstr(MI)) {
// A load from a specific PseudoSourceValue. Add precise dependencies.
diff --git a/lib/Target/SystemZ/SystemZInstrInfo.cpp b/lib/Target/SystemZ/SystemZInstrInfo.cpp
index b7dfab5..236711c 100644
--- a/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -266,30 +266,6 @@
return 0;
}
-bool SystemZInstrInfo::isInvariantLoad(const MachineInstr *MI) const {
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = MI->getOperand(i);
- // Loads from constant pools are trivially invariant.
- if (MO.isCPI())
- return true;
-
- if (MO.isGlobal())
- return isGVStub(MO.getGlobal(), TM);
-
- // If this is a load from an invariant stack slot, the load is a constant.
- if (MO.isFI()) {
- const MachineFrameInfo &MFI =
- *MI->getParent()->getParent()->getFrameInfo();
- int Idx = MO.getIndex();
- return MFI.isFixedObjectIndex(Idx) && MFI.isImmutableObjectIndex(Idx);
- }
- }
-
- // All other instances of these instructions are presumed to have other
- // issues.
- return false;
-}
-
bool
SystemZInstrInfo::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
diff --git a/lib/Target/SystemZ/SystemZInstrInfo.h b/lib/Target/SystemZ/SystemZInstrInfo.h
index ba94ced..e16d704 100644
--- a/lib/Target/SystemZ/SystemZInstrInfo.h
+++ b/lib/Target/SystemZ/SystemZInstrInfo.h
@@ -70,7 +70,6 @@
unsigned &SrcSubIdx, unsigned &DstSubIdx) const;
unsigned isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const;
unsigned isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const;
- bool isInvariantLoad(const MachineInstr *MI) const;
virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 363674b..17c8345 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -958,43 +958,6 @@
NewMI->getOperand(0).setSubReg(SubIdx);
}
-/// isInvariantLoad - Return true if the specified instruction (which is marked
-/// mayLoad) is loading from a location whose value is invariant across the
-/// function. For example, loading a value from the constant pool or from
-/// from the argument area of a function if it does not change. This should
-/// only return true of *all* loads the instruction does are invariant (if it
-/// does multiple loads).
-bool X86InstrInfo::isInvariantLoad(const MachineInstr *MI) const {
- // This code cares about loads from three cases: constant pool entries,
- // invariant argument slots, and global stubs. In order to handle these cases
- // for all of the myriad of X86 instructions, we just scan for a CP/FI/GV
- // operand and base our analysis on it. This is safe because the address of
- // none of these three cases is ever used as anything other than a load base
- // and X86 doesn't have any instructions that load from multiple places.
-
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = MI->getOperand(i);
- // Loads from constant pools are trivially invariant.
- if (MO.isCPI())
- return true;
-
- if (MO.isGlobal())
- return isGlobalStubReference(MO.getTargetFlags());
-
- // If this is a load from an invariant stack slot, the load is a constant.
- if (MO.isFI()) {
- const MachineFrameInfo &MFI =
- *MI->getParent()->getParent()->getFrameInfo();
- int Idx = MO.getIndex();
- return MFI.isFixedObjectIndex(Idx) && MFI.isImmutableObjectIndex(Idx);
- }
- }
-
- // All other instances of these instructions are presumed to have other
- // issues.
- return false;
-}
-
/// hasLiveCondCodeDef - True if MI has a condition code def, e.g. EFLAGS, that
/// is not marked dead.
static bool hasLiveCondCodeDef(MachineInstr *MI) {
diff --git a/lib/Target/X86/X86InstrInfo.h b/lib/Target/X86/X86InstrInfo.h
index 7c47433..677ec76 100644
--- a/lib/Target/X86/X86InstrInfo.h
+++ b/lib/Target/X86/X86InstrInfo.h
@@ -456,8 +456,6 @@
unsigned DestReg, unsigned SubIdx,
const MachineInstr *Orig) const;
- bool isInvariantLoad(const MachineInstr *MI) const;
-
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into a true
diff --git a/lib/Target/XCore/XCoreInstrInfo.cpp b/lib/Target/XCore/XCoreInstrInfo.cpp
index 9461e20..e616fe6 100644
--- a/lib/Target/XCore/XCoreInstrInfo.cpp
+++ b/lib/Target/XCore/XCoreInstrInfo.cpp
@@ -116,30 +116,6 @@
return 0;
}
-/// isInvariantLoad - Return true if the specified instruction (which is marked
-/// mayLoad) is loading from a location whose value is invariant across the
-/// function. For example, loading a value from the constant pool or from
-/// from the argument area of a function if it does not change. This should
-/// only return true of *all* loads the instruction does are invariant (if it
-/// does multiple loads).
-bool
-XCoreInstrInfo::isInvariantLoad(const MachineInstr *MI) const {
- // Loads from constants pools and loads from invariant argument slots are
- // invariant
- int Opcode = MI->getOpcode();
- if (Opcode == XCore::LDWCP_ru6 || Opcode == XCore::LDWCP_lru6) {
- return MI->getOperand(1).isCPI();
- }
- int FrameIndex;
- if (isLoadFromStackSlot(MI, FrameIndex)) {
- const MachineFrameInfo &MFI =
- *MI->getParent()->getParent()->getFrameInfo();
- return MFI.isFixedObjectIndex(FrameIndex) &&
- MFI.isImmutableObjectIndex(FrameIndex);
- }
- return false;
-}
-
//===----------------------------------------------------------------------===//
// Branch Analysis
//===----------------------------------------------------------------------===//
diff --git a/lib/Target/XCore/XCoreInstrInfo.h b/lib/Target/XCore/XCoreInstrInfo.h
index c97e6b4..24230ac 100644
--- a/lib/Target/XCore/XCoreInstrInfo.h
+++ b/lib/Target/XCore/XCoreInstrInfo.h
@@ -52,8 +52,6 @@
virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const;
- virtual bool isInvariantLoad(const MachineInstr *MI) const;
-
virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,