Use IntEqClasses to compute connected components of live intervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122296 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 16551ab..1ef5a4c 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -703,42 +703,10 @@
os << *this;
}
-/// ConnectedVNInfoEqClasses - Helper class that can divide VNInfos in a
-/// LiveInterval into equivalence clases of connected components. A
-/// LiveInterval that has multiple connected components can be broken into
-/// multiple LiveIntervals.
-
-void ConnectedVNInfoEqClasses::Connect(unsigned a, unsigned b) {
- 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() {
- // Assign final class numbers.
- // We use the fact that eqClass_[i] == i for class leaders.
- // For others, eqClass_[i] points to an earlier value in the same class.
- unsigned count = 0;
- for (unsigned i = 0, e = eqClass_.size(); i != e; ++i) {
- unsigned q = eqClass_[i];
- assert(q <= i && "Invariant broken");
- eqClass_[i] = q == i ? count++ : eqClass_[q];
- }
-
- return count;
-}
-
unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) {
// Create initial equivalence classes.
eqClass_.clear();
- eqClass_.reserve(LI->getNumValNums());
- for (unsigned i = 0, e = LI->getNumValNums(); i != e; ++i)
- eqClass_.push_back(i);
+ eqClass_.grow(LI->getNumValNums());
const VNInfo *used = 0, *unused = 0;
@@ -749,7 +717,7 @@
// Group all unused values into one class.
if (VNI->isUnused()) {
if (unused)
- Connect(unused->id, VNI->id);
+ eqClass_.join(unused->id, VNI->id);
unused = VNI;
continue;
}
@@ -762,36 +730,28 @@
PE = MBB->pred_end(); PI != PE; ++PI)
if (const VNInfo *PVNI =
LI->getVNInfoAt(lis_.getMBBEndIdx(*PI).getPrevSlot()))
- Connect(VNI->id, PVNI->id);
+ eqClass_.join(VNI->id, PVNI->id);
} else {
// Normal value defined by an instruction. Check for two-addr redef.
// FIXME: This could be coincidental. Should we really check for a tied
// operand constraint?
- if (const VNInfo *UVNI = LI->getVNInfoAt(VNI->def.getUseIndex()))
- Connect(VNI->id, UVNI->id);
-
- // Check for a tied operand constraint involving an early clobber def,
- // where one VN ends right before the use index and the next VN is defined
- // at the same use index.
- if (VNI->def.isUse()) {
- if (const VNInfo *PVNI = LI->getVNInfoAt(VNI->def.getLoadIndex()))
- Connect(PVNI->id, VNI->id);
- }
+ // Note that VNI->def may be a use slot for an early clobber def.
+ if (const VNInfo *UVNI = LI->getVNInfoAt(VNI->def.getPrevSlot()))
+ eqClass_.join(VNI->id, UVNI->id);
}
}
// Lump all the unused values in with the last used value.
if (used && unused)
- Connect(used->id, unused->id);
+ eqClass_.join(used->id, unused->id);
- return Renumber();
+ eqClass_.compress();
+ return eqClass_.getNumClasses();
}
void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[]) {
assert(LIV[0] && "LIV[0] must be set");
LiveInterval &LI = *LIV[0];
- // Check that they likely ran Classify() on LIV[0] first.
- assert(eqClass_.size() == LI.getNumValNums() && "Bad classification data");
// First move runs to new intervals.
LiveInterval::iterator J = LI.begin(), E = LI.end();