Sometimes a MI can define a register as well as defining a super-register at the
same time. Do not mark the "smaller" def as dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41871 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index e8d07bf..97e8671 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -249,9 +249,6 @@
}
void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
- // There is a now a proper use, forget about the last partial use.
- PhysRegPartUse[Reg] = NULL;
-
// Turn previous partial def's into read/mod/write.
for (unsigned i = 0, e = PhysRegPartDef[Reg].size(); i != e; ++i) {
MachineInstr *Def = PhysRegPartDef[Reg][i];
@@ -266,12 +263,15 @@
// A: EAX = ...
// B: = AX
// Add implicit def to A.
- if (PhysRegInfo[Reg] && !PhysRegUsed[Reg]) {
+ if (PhysRegInfo[Reg] && PhysRegInfo[Reg] != PhysRegPartUse[Reg] &&
+ !PhysRegUsed[Reg]) {
MachineInstr *Def = PhysRegInfo[Reg];
if (!Def->findRegisterDefOperand(Reg))
Def->addRegOperand(Reg, true/*IsDef*/,true/*IsImp*/);
}
+ // There is a now a proper use, forget about the last partial use.
+ PhysRegPartUse[Reg] = NULL;
PhysRegInfo[Reg] = MI;
PhysRegUsed[Reg] = true;
@@ -373,7 +373,8 @@
} else if (PhysRegPartUse[SubReg])
// Add implicit use / kill to last use of a sub-register.
addRegisterKilled(SubReg, PhysRegPartUse[SubReg], true);
- else
+ else if (LastRef != MI)
+ // This must be a def of the subreg on the same MI.
addRegisterDead(SubReg, LastRef);
}
}
@@ -381,7 +382,7 @@
if (MI) {
for (const unsigned *SuperRegs = RegInfo->getSuperRegisters(Reg);
unsigned SuperReg = *SuperRegs; ++SuperRegs) {
- if (PhysRegInfo[SuperReg]) {
+ if (PhysRegInfo[SuperReg] && PhysRegInfo[SuperReg] != MI) {
// The larger register is previously defined. Now a smaller part is
// being re-defined. Treat it as read/mod/write.
// EAX =