Switch spill weights from a basic loop depth estimation to BlockFrequencyInfo.

The main advantages here are way better heuristics, taking into account not
just loop depth but also __builtin_expect and other static heuristics and will
eventually learn how to use profile info. Most of the work in this patch is
pushing the MachineBlockFrequencyInfo analysis into the right places.

This is good for a 5% speedup on zlib's deflate (x86_64), there were some very
unfortunate spilling decisions in its hottest loop in longest_match(). Other
benchmarks I tried were mostly neutral.

This changes register allocation in subtle ways, update the tests for it.
2012-02-20-MachineCPBug.ll was deleted as it's very fragile and the instruction
it looked for was gone already (but the FileCheck pattern picked up unrelated
stuff).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184105 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 1 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 7d72f37255..ffb07a5487 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -35,6 +35,7 @@ namespace llvm {
 
   class AliasAnalysis;
   class BitVector;
+  class BlockFrequency;
   class LiveRangeCalc;
   class LiveVariables;
   class MachineDominatorTree;
@@ -99,7 +100,7 @@ namespace llvm {
     virtual ~LiveIntervals();
 
     // Calculate the spill weight to assign to a single instruction.
-    static float getSpillWeight(bool isDef, bool isUse, unsigned loopDepth);
+    static float getSpillWeight(bool isDef, bool isUse, BlockFrequency freq);
 
     LiveInterval &getInterval(unsigned Reg) {
       LiveInterval *LI = VirtRegIntervals[Reg];