Unbreak MachineLICM for instructions that reference RIP on x86-64 too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82825 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index bb0d832..8123d99 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -43,6 +43,7 @@
class VISIBILITY_HIDDEN MachineLICM : public MachineFunctionPass {
const TargetMachine *TM;
const TargetInstrInfo *TII;
+ const TargetRegisterInfo *TRI;
// Various analyses that we use...
MachineLoopInfo *LI; // Current MachineLoopInfo
@@ -135,6 +136,7 @@
Changed = false;
TM = &MF.getTarget();
TII = TM->getInstrInfo();
+ TRI = TM->getRegisterInfo();
RegInfo = &MF.getRegInfo();
// Get our Loop information...
@@ -254,8 +256,25 @@
if (Reg == 0) continue;
// Don't hoist an instruction that uses or defines a physical register.
- if (TargetRegisterInfo::isPhysicalRegister(Reg))
- return false;
+ if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ // If this is a physical register use, we can't move it. If it is a def,
+ // we can move it, but only if the def is dead.
+ if (MO.isUse()) {
+ // If the physreg has no defs anywhere, it's just an ambient register
+ // and we can freely move its uses.
+ if (!RegInfo->def_empty(Reg))
+ return false;
+ // Check for a def among the register's aliases too.
+ for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
+ if (!RegInfo->def_empty(*Alias))
+ return false;
+ // Otherwise it's safe to move.
+ continue;
+ } else if (!MO.isDead()) {
+ // A def that isn't dead. We can't move it.
+ return false;
+ }
+ }
if (!MO.isUse())
continue;