Add a LiveRangeEdit delegate callback before shrinking a live range.

The register allocator needs to adjust its live interval unions when that happens.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127774 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 940ed81465..6feae4790d 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -162,6 +162,7 @@ public:
 private:
   void LRE_WillEraseInstruction(MachineInstr*);
   bool LRE_CanEraseVirtReg(unsigned);
+  void LRE_WillShrinkVirtReg(unsigned);
 
   bool checkUncachedInterference(LiveInterval&, unsigned);
   LiveInterval *getSingleInterference(LiveInterval&, unsigned);
@@ -260,6 +261,17 @@ bool RAGreedy::LRE_CanEraseVirtReg(unsigned VirtReg) {
   return false;
 }
 
+void RAGreedy::LRE_WillShrinkVirtReg(unsigned VirtReg) {
+  unsigned PhysReg = VRM->getPhys(VirtReg);
+  if (!PhysReg)
+    return;
+
+  // Register is assigned, put it back on the queue for reassignment.
+  LiveInterval &LI = LIS->getInterval(VirtReg);
+  unassign(LI, PhysReg);
+  enqueue(&LI);
+}
+
 void RAGreedy::releaseMemory() {
   SpillerInstance.reset(0);
   LRStage.clear();