[llvm-commits] [llvm] r117631 - /llvm/trunk/lib/CodeGen/LiveInterval.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Thu Oct 28 19:40:59 2010
New Revision: 117631

URL: http://llvm.org/viewvc/llvm-project?rev=117631&view=rev
Log:
Fix broken equivalence class calculation. We could probably also use
EquvivalenceClasses.h except it looks like overkill when elements are continuous
integers.

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

Modified: llvm/trunk/lib/CodeGen/LiveInterval.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveInterval.cpp?rev=117631&r1=117630&r2=117631&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveInterval.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveInterval.cpp Thu Oct 28 19:40:59 2010
@@ -709,15 +709,14 @@
 /// multiple LiveIntervals.
 
 void ConnectedVNInfoEqClasses::Connect(unsigned a, unsigned b) {
-  unsigned eqa = eqClass_[a];
-  unsigned eqb = eqClass_[b];
-  if (eqa == eqb)
-    return;
-  // Make sure a and b are in the same class while maintaining eqClass_[i] <= i.
-  if (eqa > eqb)
-    eqClass_[a] = eqb;
-  else
-    eqClass_[b] = eqa;
+  while (eqClass_[a] != eqClass_[b]) {
+    if (eqClass_[a] > eqClass_[b])
+      std::swap(a, b);
+    unsigned t = eqClass_[b];
+    assert(t <= b && "Invariant broken");
+    eqClass_[b] = eqClass_[a];
+    b = t;
+  }
 }
 
 unsigned ConnectedVNInfoEqClasses::Renumber() {
@@ -745,8 +744,6 @@
   for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end();
        I != E; ++I) {
     const VNInfo *VNI = *I;
-    if (VNI->id == eqClass_.size())
-      eqClass_.push_back(VNI->id);
     assert(!VNI->isUnused() && "Cannot handle unused values");
     if (VNI->isPHIDef()) {
       const MachineBasicBlock *MBB = lis_.getMBBFromIndex(VNI->def);