From f0cf2d357cf5540f21400e330028045e65e60835 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Fri, 4 Mar 2011 18:51:09 +0000
Subject: [PATCH] Number SlotIndexes uniformly without looking at the number of
 defs on each instruction.

You can't really predict how many indexes will be needed from the number of
defs, so let's keep it simple.

Also remove an extra empty index that was inserted after each basic block. It
was intended for live-out ranges, but it was never used that way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127014 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SlotIndexes.cpp | 29 +++++------------------------
 1 file changed, 5 insertions(+), 24 deletions(-)

diff --git a/lib/CodeGen/SlotIndexes.cpp b/lib/CodeGen/SlotIndexes.cpp
index a495d1fd832..28e3fb5c159 100644
--- a/lib/CodeGen/SlotIndexes.cpp
+++ b/lib/CodeGen/SlotIndexes.cpp
@@ -75,8 +75,6 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
     // Insert an index for the MBB start.
     SlotIndex blockStartIndex(back(), SlotIndex::LOAD);
 
-    index += SlotIndex::NUM;
-
     for (MachineBasicBlock::iterator miItr = mbb->begin(), miEnd = mbb->end();
          miItr != miEnd; ++miItr) {
       MachineInstr *mi = miItr;
@@ -84,27 +82,16 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
         continue;
 
       // Insert a store index for the instr.
-      push_back(createEntry(mi, index));
+      push_back(createEntry(mi, index += SlotIndex::InstrDist));
 
       // Save this base index in the maps.
-      mi2iMap.insert(
-        std::make_pair(mi, SlotIndex(back(), SlotIndex::LOAD)));
+      mi2iMap.insert(std::make_pair(mi, SlotIndex(back(), SlotIndex::LOAD)));
  
       ++functionSize;
-
-      unsigned Slots = mi->getDesc().getNumDefs();
-      if (Slots == 0)
-        Slots = 1;
-
-      index += (Slots + 1) * SlotIndex::NUM;
     }
 
-    // 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));
+    // We insert one blank instructions between basic blocks.
+    push_back(createEntry(0, index += SlotIndex::InstrDist));
 
     SlotIndex blockEndIndex(back(), SlotIndex::LOAD);
     mbb2IdxMap.insert(
@@ -123,13 +110,7 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
 }
 
 void SlotIndexes::renumberIndexes() {
-
   // Renumber updates the index of every element of the index list.
-  // If all instrs in the function have been allocated an index (which has been
-  // placed in the index list in the order of instruction iteration) then the
-  // resulting numbering will match what would have been generated by the
-  // pass during the initial numbering of the function if the new instructions
-  // had been present.
   DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");
   ++NumRenumPasses;
 
@@ -138,7 +119,7 @@ void SlotIndexes::renumberIndexes() {
   for (IndexListEntry *curEntry = front(); curEntry != getTail();
        curEntry = curEntry->getNext()) {
     curEntry->setIndex(index);
-    index += 4*SlotIndex::NUM;
+    index += SlotIndex::InstrDist;
   }
 }
 
-- 
2.34.1