Extract method for detecting constant unallocatable physregs.
It is safe to move uses of such registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148259 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index e7c2843..77ea4f3 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -81,8 +81,6 @@
MachineLoop *CurLoop; // The current loop we are working on.
MachineBasicBlock *CurPreheader; // The preheader for CurLoop.
- BitVector AllocatableSet;
-
// Track 'estimated' register pressure.
SmallSet<unsigned, 32> RegSeen;
SmallVector<unsigned, 8> RegPressure;
@@ -331,7 +329,6 @@
MFI = MF.getFrameInfo();
MRI = &MF.getRegInfo();
InstrItins = TM->getInstrItineraryData();
- AllocatableSet = TRI->getAllocatableSet(MF);
if (PreRegAlloc) {
// Estimate register pressure during pre-regalloc pass.
@@ -905,18 +902,8 @@
// 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,
// it could get allocated to something with a def during allocation.
- if (!MRI->def_empty(Reg))
+ if (!MRI->isConstantPhysReg(Reg, *I.getParent()->getParent()))
return false;
- if (AllocatableSet.test(Reg))
- return false;
- // Check for a def among the register's aliases too.
- for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- if (!MRI->def_empty(AliasReg))
- return false;
- if (AllocatableSet.test(AliasReg))
- return false;
- }
// Otherwise it's safe to move.
continue;
} else if (!MO.isDead()) {
diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp
index 67291a0..6ec55247 100644
--- a/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/lib/CodeGen/MachineRegisterInfo.cpp
@@ -263,3 +263,21 @@
void MachineRegisterInfo::freezeReservedRegs(const MachineFunction &MF) {
ReservedRegs = TRI->getReservedRegs(MF);
}
+
+bool MachineRegisterInfo::isConstantPhysReg(unsigned PhysReg,
+ const MachineFunction &MF) const {
+ assert(TargetRegisterInfo::isPhysicalRegister(PhysReg));
+
+ // Check if any overlapping register is modified.
+ for (const unsigned *R = TRI->getOverlaps(PhysReg); *R; ++R)
+ if (!def_empty(*R))
+ return false;
+
+ // Check if any overlapping register is allocatable so it may be used later.
+ if (AllocatableRegs.empty())
+ AllocatableRegs = TRI->getAllocatableSet(MF);
+ for (const unsigned *R = TRI->getOverlaps(PhysReg); *R; ++R)
+ if (AllocatableRegs.test(*R))
+ return false;
+ return true;
+}
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index e47360d..817e5cb 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -485,21 +485,8 @@
// 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,
// it could get allocated to something with a def during allocation.
- if (!MRI->def_empty(Reg))
+ if (!MRI->isConstantPhysReg(Reg, *MBB->getParent()))
return NULL;
-
- if (AllocatableSet.test(Reg))
- return NULL;
-
- // Check for a def among the register's aliases too.
- for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- if (!MRI->def_empty(AliasReg))
- return NULL;
-
- if (AllocatableSet.test(AliasReg))
- return NULL;
- }
} else if (!MO.isDead()) {
// A def that isn't dead. We can't move it.
return NULL;
diff --git a/lib/CodeGen/TargetInstrInfoImpl.cpp b/lib/CodeGen/TargetInstrInfoImpl.cpp
index 018b5e5..be25855 100644
--- a/lib/CodeGen/TargetInstrInfoImpl.cpp
+++ b/lib/CodeGen/TargetInstrInfoImpl.cpp
@@ -380,7 +380,6 @@
const MachineRegisterInfo &MRI = MF.getRegInfo();
const TargetMachine &TM = MF.getTarget();
const TargetInstrInfo &TII = *TM.getInstrInfo();
- const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
// Remat clients assume operand 0 is the defined register.
if (!MI->getNumOperands() || !MI->getOperand(0).isReg())
@@ -432,19 +431,8 @@
// 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,
// it could get allocated to something with a def during allocation.
- if (!MRI.def_empty(Reg))
+ if (!MRI.isConstantPhysReg(Reg, MF))
return false;
- BitVector AllocatableRegs = TRI.getAllocatableSet(MF, 0);
- if (AllocatableRegs.test(Reg))
- return false;
- // Check for a def among the register's aliases too.
- for (const unsigned *Alias = TRI.getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- if (!MRI.def_empty(AliasReg))
- return false;
- if (AllocatableRegs.test(AliasReg))
- return false;
- }
} else {
// A physreg def. We can't remat it.
return false;