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Fix PR5410: LiveVariables lost subreg def:

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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
This commit is contained in:
Evan Cheng
2009-11-13 20:36:40 +00:00
parent 87d21b92fc
commit 236490d870
2 changed files with 27 additions and 1 deletions
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8
lib/CodeGen/LiveVariables.cpp
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@ -230,8 +230,9 @@ MachineInstr *LiveVariables::FindLastPartialDef(unsigned Reg,
/// 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 @@ void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
}
}
}
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;