Check hint registers for interference only once before evictions

llvm-svn: 196536

2 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/AllocationOrder.h b/llvm/lib/CodeGen/AllocationOrder.h
index aed461a7ed0..64ff2a7ce83 100644
--- a/llvm/lib/CodeGen/AllocationOrder.h
+++ b/llvm/lib/CodeGen/AllocationOrder.h
@@ -45,10 +45,12 @@ public:
   /// Return the next physical register in the allocation order, or 0.
   /// It is safe to call next() again after it returned 0, it will keep
   /// returning 0 until rewind() is called.
-  unsigned next() {
+  unsigned next(unsigned Limit = 0) {
     if (Pos < 0)
       return Hints.end()[Pos++];
-    while (Pos < int(Order.size())) {
+    if (!Limit)
+      Limit = Order.size();
+    while (Pos < int(Limit)) {
       unsigned Reg = Order[Pos++];
       if (!isHint(Reg))
         return Reg;
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
index 3a02aaec344..7ddc4d5ad86 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.cpp
+++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -723,7 +723,7 @@ unsigned RAGreedy::tryEvict(LiveInterval &VirtReg,
   }
 
   Order.rewind();
-  while (unsigned PhysReg = Order.nextWithDups(OrderLimit)) {
+  while (unsigned PhysReg = Order.next(OrderLimit)) {
     if (TRI->getCostPerUse(PhysReg) >= CostPerUseLimit)
       continue;
     // The first use of a callee-saved register in a function has cost 1.