Convert RAGreedy to LiveRegMatrix interference checking.

Stop depending on the LiveIntervalUnions in RegAllocBase, they are about
to be removed.

The changes are mostly replacing register alias iterators with regunit
iterators, and querying LiveRegMatrix instrad of RegAllocBase.

InterferenceCache is converted to work with per-regunit
LiveIntervalUnions, and it checks fixed regunit interference separately,
using the fixed live intervals provided by LiveIntervalAnalysis.

The local splitting helper calcGapWeights() is also considering fixed
regunit interference which is kept on the side now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158867 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 8 deletions

diff --git a/lib/CodeGen/InterferenceCache.h b/lib/CodeGen/InterferenceCache.h
index 485a325aa1..3c928a5086 100644
--- a/lib/CodeGen/InterferenceCache.h
+++ b/lib/CodeGen/InterferenceCache.h
@@ -7,7 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// InterferenceCache remembers per-block interference in LiveIntervalUnions.
+// InterferenceCache remembers per-block interference from LiveIntervalUnions,
+// fixed RegUnit interference, and register masks.
 //
 //===----------------------------------------------------------------------===//
 
@@ -59,14 +60,31 @@ class InterferenceCache {
     /// PrevPos - The previous position the iterators were moved to.
     SlotIndex PrevPos;
 
-    /// AliasTags - A LiveIntervalUnion pointer and tag for each alias of
-    /// PhysReg.
-    SmallVector<std::pair<LiveIntervalUnion*, unsigned>, 8> Aliases;
+    /// RegUnitInfo - Information tracked about each RegUnit in PhysReg.
+    /// When PrevPos is set, the iterators are valid as if advanceTo(PrevPos)
+    /// had just been called.
+    struct RegUnitInfo {
+      /// Iterator pointing into the LiveIntervalUnion containing virtual
+      /// register interference.
+      LiveIntervalUnion::SegmentIter VirtI;
 
-    typedef LiveIntervalUnion::SegmentIter Iter;
+      /// Tag of the LIU last time we looked.
+      unsigned VirtTag;
 
-    /// Iters - an iterator for each alias
-    SmallVector<Iter, 8> Iters;
+      /// Fixed interference in RegUnit.
+      LiveInterval *Fixed;
+
+      /// Iterator pointing into the fixed RegUnit interference.
+      LiveInterval::iterator FixedI;
+
+      RegUnitInfo(LiveIntervalUnion &LIU) : VirtTag(LIU.getTag()), Fixed(0) {
+        VirtI.setMap(LIU.getMap());
+      }
+    };
+
+    /// Info for each RegUnit in PhysReg. It is very rare ofr a PHysReg to have
+    /// more than 4 RegUnits.
+    SmallVector<RegUnitInfo, 4> RegUnits;
 
     /// Blocks - Interference for each block in the function.
     SmallVector<BlockInterference, 8> Blocks;
@@ -91,7 +109,7 @@ class InterferenceCache {
 
     bool hasRefs() const { return RefCount > 0; }
 
-    void revalidate();
+    void revalidate(LiveIntervalUnion *LIUArray, const TargetRegisterInfo *TRI);
 
     /// valid - Return true if this is a valid entry for physReg.
     bool valid(LiveIntervalUnion *LIUArray, const TargetRegisterInfo *TRI);