[llvm-commits] [llvm] r118747 - in /llvm/trunk: include/llvm/CodeGen/SlotIndexes.h lib/CodeGen/SlotIndexes.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Wed Nov 10 18:19:20 2010
New Revision: 118747

URL: http://llvm.org/viewvc/llvm-project?rev=118747&view=rev
Log:
Insert two blank SlotIndexes between basic blocks instead of just one.

This is the first small step towards using closed intervals for liveness instead
of the half-open intervals we're using now.

We want to be able to distinguish between a SlotIndex that represents a variable
being live-out of a basic block, and an index representing a variable live-in to
its successor.

That requires two separate indexes between blocks. One for live-outs and one for
live-ins.

With this change, getMBBEndIdx(MBB).getPrevSlot() becomes stable so it stays
greater than any instructions inserted at the end of MBB.

Modified:
    llvm/trunk/include/llvm/CodeGen/SlotIndexes.h
    llvm/trunk/lib/CodeGen/SlotIndexes.cpp

Modified: llvm/trunk/include/llvm/CodeGen/SlotIndexes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SlotIndexes.h?rev=118747&r1=118746&r2=118747&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SlotIndexes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SlotIndexes.h Wed Nov 10 18:19:20 2010
@@ -738,6 +738,7 @@
       MachineFunction::iterator nextMBB =
         llvm::next(MachineFunction::iterator(mbb));
       IndexListEntry *startEntry = createEntry(0, 0);
+      IndexListEntry *stopEntry = createEntry(0, 0);
       IndexListEntry *nextEntry = 0;
 
       if (nextMBB == mbb->getParent()->end()) {
@@ -747,6 +748,7 @@
       }
 
       insert(nextEntry, startEntry);
+      insert(nextEntry, stopEntry);
 
       SlotIndex startIdx(startEntry, SlotIndex::LOAD);
       SlotIndex endIdx(nextEntry, SlotIndex::LOAD);

Modified: llvm/trunk/lib/CodeGen/SlotIndexes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SlotIndexes.cpp?rev=118747&r1=118746&r2=118747&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SlotIndexes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SlotIndexes.cpp Wed Nov 10 18:19:20 2010
@@ -127,8 +127,12 @@
       index += (Slots + 1) * SlotIndex::NUM;
     }
 
-    // One blank instruction at the end.
-    push_back(createEntry(0, index));    
+    // We insert two blank instructions between basic blocks.
+    // One to represent live-out registers and one to represent live-ins.
+    push_back(createEntry(0, index));
+    index += SlotIndex::NUM;
+
+    push_back(createEntry(0, index));
 
     SlotIndex blockEndIndex(back(), SlotIndex::LOAD);
     mbb2IdxMap.insert(