Freeze the reserved registers as soon as isel is complete.
Also provide an MRI::getReservedRegs() function to access the frozen
register set, and isReserved() and isAllocatable() methods to test
individual registers.
The various implementations of TRI::getReservedRegs() are quite
complicated, and many passes need to look at the reserved register set.
This patch makes it possible for these passes to use the cached copy in
MRI, avoiding a lot of malloc traffic and repeated calculations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165982 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 8fc9c70..c314fa5 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -474,6 +474,11 @@
MRI.replaceRegWith(From, To);
}
+ // Freeze the set of reserved registers now that MachineFrameInfo has been
+ // set up. All the information required by getReservedRegs() should be
+ // available now.
+ MRI.freezeReservedRegs(*MF);
+
// Release function-specific state. SDB and CurDAG are already cleared
// at this point.
FuncInfo->clear();