[llvm-commits] [llvm] r131521 - /llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Tue May 17 23:18:19 2011
New Revision: 131521

URL: http://llvm.org/viewvc/llvm-project?rev=131521&view=rev
Log:
Properly shrink live ranges after deleting dead copies. Clean up after all joined copies.

LiveInterval::shrinkToUses recomputes the live range from scratch instead of
removing snippets. This should avoid the problem with dangling live ranges.

Leave physreg identity copies alone. They can be created when joining a virtreg
with a physreg. They don't affect register allocation, and they will be removed
by the rewriter.

Modified:
    llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp

Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=131521&r1=131520&r2=131521&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Tue May 17 23:18:19 2011
@@ -1038,6 +1038,7 @@
 
   // If they are already joined we continue.
   if (CP.getSrcReg() == CP.getDstReg()) {
+    markAsJoined(CopyMI);
     DEBUG(dbgs() << "\tCopy already coalesced.\n");
     return false;  // Not coalescable.
   }
@@ -1696,13 +1697,11 @@
           // or else the scavenger may complain. LowerSubregs will
           // delete them later.
           DoDelete = false;
-        
+
         if (MI->allDefsAreDead()) {
-          if (li_->hasInterval(SrcReg)) {
-            LiveInterval &li = li_->getInterval(SrcReg);
-            if (!ShortenDeadCopySrcLiveRange(li, MI))
-              ShortenDeadCopyLiveRange(li, MI);
-          }
+          if (TargetRegisterInfo::isVirtualRegister(SrcReg) &&
+              li_->hasInterval(SrcReg))
+            li_->shrinkToUses(&li_->getInterval(SrcReg));
           DoDelete = true;
         }
         if (!DoDelete) {
@@ -1754,24 +1753,6 @@
           DeadDefs.clear();
       }
 
-      // If the move will be an identity move delete it
-      if (MI->isIdentityCopy()) {
-        unsigned SrcReg = MI->getOperand(1).getReg();
-        if (li_->hasInterval(SrcReg)) {
-          LiveInterval &RegInt = li_->getInterval(SrcReg);
-          // If def of this move instruction is dead, remove its live range
-          // from the destination register's live interval.
-          if (MI->allDefsAreDead()) {
-            if (!ShortenDeadCopySrcLiveRange(RegInt, MI))
-              ShortenDeadCopyLiveRange(RegInt, MI);
-          }
-        }
-        li_->RemoveMachineInstrFromMaps(MI);
-        mii = mbbi->erase(mii);
-        ++numPeep;
-        continue;
-      }
-
       ++mii;
 
       // Check for now unnecessary kill flags.