Changes in directory llvm/lib/CodeGen:
LiveVariables.cpp updated: 1.84 -> 1.85
---
Log message:
Properly handle kills of a physical register which has sub-registers that are
read by later instructions.
---
Diffs of the changes: (+73 -13)
LiveVariables.cpp | 86 +++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 73 insertions(+), 13 deletions(-)
Index: llvm/lib/CodeGen/LiveVariables.cpp
diff -u llvm/lib/CodeGen/LiveVariables.cpp:1.84
llvm/lib/CodeGen/LiveVariables.cpp:1.85
--- llvm/lib/CodeGen/LiveVariables.cpp:1.84 Mon May 14 15:39:18 2007
+++ llvm/lib/CodeGen/LiveVariables.cpp Tue Jun 26 16:03:35 2007
@@ -286,38 +286,85 @@
PhysRegPartUse[SuperReg] = MI;
}
+bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *RefMI,
+ SmallSet<unsigned, 4> &SubKills) {
+ for (const unsigned *SubRegs = RegInfo->getImmediateSubRegisters(Reg);
+ unsigned SubReg = *SubRegs; ++SubRegs) {
+ MachineInstr *LastRef = PhysRegInfo[SubReg];
+ if (LastRef != RefMI)
+ SubKills.insert(SubReg);
+ else if (!HandlePhysRegKill(SubReg, RefMI, SubKills))
+ SubKills.insert(SubReg);
+ }
+
+ if (*RegInfo->getImmediateSubRegisters(Reg) == 0) {
+ // No sub-registers, just check if reg is killed by RefMI.
+ if (PhysRegInfo[Reg] == RefMI)
+ return true;
+ } else if (SubKills.empty())
+ // None of the sub-registers are killed elsewhere...
+ return true;
+ return false;
+}
+
+void LiveVariables::addRegisterKills(unsigned Reg, MachineInstr *MI,
+ SmallSet<unsigned, 4> &SubKills) {
+ if (SubKills.count(Reg) == 0)
+ addRegisterKilled(Reg, MI, true);
+ else {
+ for (const unsigned *SubRegs = RegInfo->getImmediateSubRegisters(Reg);
+ unsigned SubReg = *SubRegs; ++SubRegs)
+ addRegisterKills(SubReg, MI, SubKills);
+ }
+}
+
+bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *RefMI) {
+ SmallSet<unsigned, 4> SubKills;
+ if (HandlePhysRegKill(Reg, RefMI, SubKills)) {
+ addRegisterKilled(Reg, RefMI);
+ return true;
+ } else {
+ // Some sub-registers are killed by another MI.
+ for (const unsigned *SubRegs = RegInfo->getImmediateSubRegisters(Reg);
+ unsigned SubReg = *SubRegs; ++SubRegs)
+ addRegisterKills(SubReg, RefMI, SubKills);
+ return false;
+ }
+}
+
void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
// Does this kill a previous version of this register?
if (MachineInstr *LastRef = PhysRegInfo[Reg]) {
- if (PhysRegUsed[Reg])
- addRegisterKilled(Reg, LastRef);
- else if (PhysRegPartUse[Reg])
+ if (PhysRegUsed[Reg]) {
+ if (!HandlePhysRegKill(Reg, LastRef)) {
+ if (PhysRegPartUse[Reg])
+ addRegisterKilled(Reg, PhysRegPartUse[Reg], true);
+ }
+ } else if (PhysRegPartUse[Reg])
// Add implicit use / kill to last use of a sub-register.
addRegisterKilled(Reg, PhysRegPartUse[Reg], true);
else
addRegisterDead(Reg, LastRef);
}
- PhysRegInfo[Reg] = MI;
- PhysRegUsed[Reg] = false;
- PhysRegPartUse[Reg] = NULL;
for (const unsigned *SubRegs = RegInfo->getSubRegisters(Reg);
unsigned SubReg = *SubRegs; ++SubRegs) {
if (MachineInstr *LastRef = PhysRegInfo[SubReg]) {
- if (PhysRegUsed[SubReg])
- addRegisterKilled(SubReg, LastRef);
- else if (PhysRegPartUse[SubReg])
+ if (PhysRegUsed[SubReg]) {
+ if (!HandlePhysRegKill(SubReg, LastRef)) {
+ if (PhysRegPartUse[SubReg])
+ addRegisterKilled(SubReg, PhysRegPartUse[SubReg], true);
+ }
+ //addRegisterKilled(SubReg, LastRef);
+ } else if (PhysRegPartUse[SubReg])
// Add implicit use / kill to last use of a sub-register.
addRegisterKilled(SubReg, PhysRegPartUse[SubReg], true);
else
addRegisterDead(SubReg, LastRef);
}
- PhysRegInfo[SubReg] = MI;
- PhysRegUsed[SubReg] = false;
- PhysRegPartUse[SubReg] = NULL;
}
- if (MI)
+ if (MI) {
for (const unsigned *SuperRegs = RegInfo->getSuperRegisters(Reg);
unsigned SuperReg = *SuperRegs; ++SuperRegs) {
if (PhysRegInfo[SuperReg]) {
@@ -334,6 +381,17 @@
// Remember this partial def.
PhysRegPartDef[SuperReg].push_back(MI);
}
+ }
+
+ PhysRegInfo[Reg] = MI;
+ PhysRegUsed[Reg] = false;
+ PhysRegPartUse[Reg] = NULL;
+ for (const unsigned *SubRegs = RegInfo->getSubRegisters(Reg);
+ unsigned SubReg = *SubRegs; ++SubRegs) {
+ PhysRegInfo[SubReg] = MI;
+ PhysRegUsed[SubReg] = false;
+ PhysRegPartUse[SubReg] = NULL;
+ }
}
}
@@ -465,6 +523,8 @@
// Clear some states between BB's. These are purely local information.
for (unsigned i = 0; i != NumRegs; ++i)
PhysRegPartDef[i].clear();
+ std::fill(PhysRegInfo, PhysRegInfo + NumRegs, (MachineInstr*)0);
+ std::fill(PhysRegUsed, PhysRegUsed + NumRegs, false);
std::fill(PhysRegPartUse, PhysRegPartUse + NumRegs, (MachineInstr*)0);
}
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