Extract method for detecting constant unallocatable physregs.
It is safe to move uses of such registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148259 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index e7c2843..77ea4f3 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -81,8 +81,6 @@
MachineLoop *CurLoop; // The current loop we are working on.
MachineBasicBlock *CurPreheader; // The preheader for CurLoop.
- BitVector AllocatableSet;
-
// Track 'estimated' register pressure.
SmallSet<unsigned, 32> RegSeen;
SmallVector<unsigned, 8> RegPressure;
@@ -331,7 +329,6 @@
MFI = MF.getFrameInfo();
MRI = &MF.getRegInfo();
InstrItins = TM->getInstrItineraryData();
- AllocatableSet = TRI->getAllocatableSet(MF);
if (PreRegAlloc) {
// Estimate register pressure during pre-regalloc pass.
@@ -905,18 +902,8 @@
// If the physreg has no defs anywhere, it's just an ambient register
// and we can freely move its uses. Alternatively, if it's allocatable,
// it could get allocated to something with a def during allocation.
- if (!MRI->def_empty(Reg))
+ if (!MRI->isConstantPhysReg(Reg, *I.getParent()->getParent()))
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) {
- unsigned AliasReg = *Alias;
- if (!MRI->def_empty(AliasReg))
- return false;
- if (AllocatableSet.test(AliasReg))
- return false;
- }
// Otherwise it's safe to move.
continue;
} else if (!MO.isDead()) {