Fix PR5410: LiveVariables lost subreg def:
D0<def,dead> = ...
...
= S0<use, kill>
S0<def> = ...
...
D0<def> =
The first D0 def is correctly marked dead, however, livevariables should have
added an implicit def of S0 or we end up with a use without a def.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88690 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index cba0371..16a79bb 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -230,8 +230,9 @@
/// implicit defs to a machine instruction if there was an earlier def of its
/// super-register.
void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
+ MachineInstr *LastDef = PhysRegDef[Reg];
// If there was a previous use or a "full" def all is well.
- if (!PhysRegDef[Reg] && !PhysRegUse[Reg]) {
+ if (!LastDef && !PhysRegUse[Reg]) {
// Otherwise, the last sub-register def implicitly defines this register.
// e.g.
// AH =
@@ -265,6 +266,11 @@
}
}
}
+ else if (LastDef && !PhysRegUse[Reg] &&
+ !LastDef->findRegisterDefOperand(Reg))
+ // Last def defines the super register, add an implicit def of reg.
+ LastDef->addOperand(MachineOperand::CreateReg(Reg,
+ true/*IsDef*/, true/*IsImp*/));
// Remember this use.
PhysRegUse[Reg] = MI;