Remove MachineRegisterInfo::getLastVirtReg(), it was giving wrong results

when no virtual registers have been allocated.

It was only used to resize IndexedMaps, so provide an IndexedMap::resize()
method such that

 Map.grow(MRI.getLastVirtReg());

can be replaced with the simpler

 Map.resize(MRI.getNumVirtRegs());

This works correctly when no virtuals are allocated, and it bypasses the to/from
index conversions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123130 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 8 deletions

diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index bc295ef30c..df8a021d14 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -88,14 +88,14 @@ bool VirtRegMap::runOnMachineFunction(MachineFunction &mf) {
 }
 
 void VirtRegMap::grow() {
-  unsigned LastVirtReg = MF->getRegInfo().getLastVirtReg();
-  Virt2PhysMap.grow(LastVirtReg);
-  Virt2StackSlotMap.grow(LastVirtReg);
-  Virt2ReMatIdMap.grow(LastVirtReg);
-  Virt2SplitMap.grow(LastVirtReg);
-  Virt2SplitKillMap.grow(LastVirtReg);
-  ReMatMap.grow(LastVirtReg);
-  ImplicitDefed.resize(MF->getRegInfo().getNumVirtRegs());
+  unsigned NumRegs = MF->getRegInfo().getNumVirtRegs();
+  Virt2PhysMap.resize(NumRegs);
+  Virt2StackSlotMap.resize(NumRegs);
+  Virt2ReMatIdMap.resize(NumRegs);
+  Virt2SplitMap.resize(NumRegs);
+  Virt2SplitKillMap.resize(NumRegs);
+  ReMatMap.resize(NumRegs);
+  ImplicitDefed.resize(NumRegs);
 }
 
 unsigned VirtRegMap::createSpillSlot(const TargetRegisterClass *RC) {