Patch to fix PR337. Make sure to mark all aliased physical registers as used
when we see a read of a register. This is important in cases like:
AL = ...
AH = ...
= AX
The read of AX must make both the AL and AH defs live until the use.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13444 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 759a0b3..f1a7d9e 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -126,6 +126,12 @@
void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
PhysRegInfo[Reg] = MI;
PhysRegUsed[Reg] = true;
+
+ for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+ unsigned Alias = *AliasSet; ++AliasSet) {
+ PhysRegInfo[Alias] = MI;
+ PhysRegUsed[Alias] = true;
+ }
}
void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
@@ -140,11 +146,10 @@
PhysRegUsed[Reg] = false;
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
- *AliasSet; ++AliasSet) {
- unsigned Alias = *AliasSet;
+ unsigned Alias = *AliasSet; ++AliasSet) {
if (MachineInstr *LastUse = PhysRegInfo[Alias]) {
if (PhysRegUsed[Alias])
- RegistersKilled.insert(std::make_pair(LastUse, Alias));
+ RegistersKilled.insert(std::make_pair(LastUse, Alias));
else
RegistersDead.insert(std::make_pair(LastUse, Alias));
}