Renumber slot indexes uniformly instead of spacing according to the number of defs.

There are probably much larger speedups to be had by renumbering locally instead
of looping over the whole function. For now, the greedy register allocator is
25% faster.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126926 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SlotIndexes.cpp b/lib/CodeGen/SlotIndexes.cpp
index f18854be856d370bf05996f79c12417e8882fd1a..73adb92101d7447e5283e1c6f40cbfc0d5b5f939 100644 (file)
--- a/lib/CodeGen/SlotIndexes.cpp
+++ b/lib/CodeGen/SlotIndexes.cpp
@@ -129,26 +129,12 @@ void SlotIndexes::renumberIndexes() {
   // had been present.
   DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");
 
-  functionSize = 0;
   unsigned index = 0;
 
   for (IndexListEntry *curEntry = front(); curEntry != getTail();
        curEntry = curEntry->getNext()) {
-
     curEntry->setIndex(index);
-
-    if (curEntry->getInstr() == 0) {
-      // MBB start entry. Just step index by 1.
-      index += SlotIndex::NUM;
-    }
-    else {
-      ++functionSize;
-      unsigned Slots = curEntry->getInstr()->getDesc().getNumDefs();
-      if (Slots == 0)
-        Slots = 1;
-
-      index += (Slots + 1) * SlotIndex::NUM;
-    }
+    index += 4*SlotIndex::NUM;
   }
 }