[llvm-commits] [llvm] r76680 - in /llvm/trunk/lib/CodeGen: LiveInterval.cpp SimpleRegisterCoalescing.cpp

[David Greene]

Author: greened
Date: Tue Jul 21 18:36:14 2009
New Revision: 76680

URL: http://llvm.org/viewvc/llvm-project?rev=76680&view=rev
Log:

Add some support for iterative coalescers to calculate a joined live
range's weight properly.  This is turned off right now in the sense that
you'll get an assert if you get into a situation that can only be caused
by an iterative coalescer.  All other code paths operate exactly as
before so there is no functional change with this patch.  The asserts
should be disabled if/when an iterative coalescer gets added to trunk.

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

Modified: llvm/trunk/lib/CodeGen/LiveInterval.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveInterval.cpp?rev=76680&r1=76679&r2=76680&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/LiveInterval.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveInterval.cpp Tue Jul 21 18:36:14 2009
@@ -503,7 +503,23 @@
     InsertPos = addRangeFrom(*I, InsertPos);
   }
 
-  weight += Other.weight;
+  // If either of these intervals was spilled, the weight is the
+  // weight of the non-spilled interval.  This can only happen with
+  // iterative coalescers.
+
+  if (weight == HUGE_VALF && !TargetRegisterInfo::isPhysicalRegister(reg)) {
+    // Remove this assert if you have an iterative coalescer
+    assert(0 && "Joining to spilled interval");
+    weight = Other.weight;
+  }
+  else if (Other.weight != HUGE_VALF) {
+    weight += Other.weight;
+  }
+  else {
+    // Remove this assert if you have an iterative coalescer
+    assert(0 && "Joining from spilled interval");
+  }
+  // Otherwise the weight stays the same
 
   // Update regalloc hint if currently there isn't one.
   if (TargetRegisterInfo::isVirtualRegister(reg) &&

Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=76680&r1=76679&r2=76680&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Tue Jul 21 18:36:14 2009
@@ -1969,7 +1969,24 @@
     LHSValNo->setHasPHIKill(true);
   LHS.addKills(LHSValNo, VNI->kills);
   LHS.MergeRangesInAsValue(RHS, LHSValNo);
-  LHS.weight += RHS.weight;
+
+  // If either of these intervals was spilled, the weight is the
+  // weight of the non-spilled interval.  This can only happen
+  // with iterative coalescers.
+  if (LHS.weight == HUGE_VALF && !TargetRegisterInfo::isPhysicalRegister(LHS.reg)) {
+    // Remove this assert if you have an iterative coalescer
+    assert(0 && "Joining to spilled interval");
+    LHS.weight = RHS.weight;
+  }
+  else if (RHS.weight != HUGE_VALF) {
+    LHS.weight += RHS.weight;
+  }
+  else {
+    // Remove this assert if you have an iterative coalescer
+    assert(0 && "Joining from spilled interval");
+  }
+
+  // Otherwise the LHS weight stays the same
 
   // Update regalloc hint if both are virtual registers.
   if (TargetRegisterInfo::isVirtualRegister(LHS.reg) &&