diff options
| author | Dan Gohman <gohman@apple.com> | 2009-09-26 02:34:00 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2009-09-26 02:34:00 +0000 |
| commit | 45094e34bcbb133aa0bbe55710e25369df0e02ed (patch) | |
| tree | 02c3bbb0b3a6c27fd49d3d5277a04a6b2cc2a928 /lib/CodeGen/MachineLICM.cpp | |
| parent | 22cb6579b3ab33610f166b264833fa945e8e2ade (diff) | |
Don't hoist or sink instructions with physreg uses if the physreg is
allocatable. Even if it doesn't appear to have any defs, it may latter
on after register allocation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82834 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineLICM.cpp')
| -rw-r--r-- | lib/CodeGen/MachineLICM.cpp | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp index 8123d99680..61678f1d7c 100644 --- a/lib/CodeGen/MachineLICM.cpp +++ b/lib/CodeGen/MachineLICM.cpp @@ -44,6 +44,7 @@ namespace { const TargetMachine *TM; const TargetInstrInfo *TII; const TargetRegisterInfo *TRI; + BitVector AllocatableSet; // Various analyses that we use... MachineLoopInfo *LI; // Current MachineLoopInfo @@ -138,6 +139,7 @@ bool MachineLICM::runOnMachineFunction(MachineFunction &MF) { TII = TM->getInstrInfo(); TRI = TM->getRegisterInfo(); RegInfo = &MF.getRegInfo(); + AllocatableSet = TRI->getAllocatableSet(MF); // Get our Loop information... LI = &getAnalysis<MachineLoopInfo>(); @@ -261,13 +263,20 @@ bool MachineLICM::IsLoopInvariantInst(MachineInstr &I) { // 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. + // and we can freely move its uses. Alternatively, if it's allocatable, + // it could get allocated to something with a def during allocation. if (!RegInfo->def_empty(Reg)) return false; + if (AllocatableSet.test(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)) + for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + unsigned AliasReg = *Alias; + if (!RegInfo->def_empty(AliasReg)) + return false; + if (AllocatableSet.test(AliasReg)) return false; + } // Otherwise it's safe to move. continue; } else if (!MO.isDead()) { |