//
// Synthesize missing register class intersections.
//
// Make sure that sub-classes of RC exists such that getCommonSubClass(RC, X)
// returns a maximal register class for all X.
//
void CodeGenRegBank::inferCommonSubClass(CodeGenRegisterClass *RC) {
for (unsigned rci = 0, rce = RegClasses.size(); rci != rce; ++rci) {
CodeGenRegisterClass *RC1 = RC;
CodeGenRegisterClass *RC2 = RegClasses[rci];
if (RC1 == RC2)
continue;
// Compute the set intersection of RC1 and RC2.
const CodeGenRegister::Set &Memb1 = RC1->getMembers();
const CodeGenRegister::Set &Memb2 = RC2->getMembers();
CodeGenRegister::Set Intersection;
std::set_intersection(Memb1.begin(), Memb1.end(),
Memb2.begin(), Memb2.end(),
std::inserter(Intersection, Intersection.begin()),
CodeGenRegister::Less());
// Skip disjoint class pairs.
if (Intersection.empty())
continue;
// If RC1 and RC2 have different spill sizes or alignments, use the
// larger size for sub-classing. If they are equal, prefer RC1.
if (RC2->SpillSize > RC1->SpillSize ||
(RC2->SpillSize == RC1->SpillSize &&
RC2->SpillAlignment > RC1->SpillAlignment))
std::swap(RC1, RC2);
getOrCreateSubClass(RC1, &Intersection,
RC1->getName() + "_and_" + RC2->getName());
}
}
void CodeGenRegBank::inferMatchingSuperRegClass(CodeGenRegisterClass *RC,
unsigned FirstSubRegRC) {
SmallVector<std::pair<const CodeGenRegister*,
const CodeGenRegister*>, 16> SSPairs;
// Iterate in SubRegIndex numerical order to visit synthetic indices last.
for (unsigned sri = 0, sre = SubRegIndices.size(); sri != sre; ++sri) {
Record *SubIdx = SubRegIndices[sri];
// Skip indexes that aren't fully supported by RC's registers. This was
// computed by inferSubClassWithSubReg() above which should have been
// called first.
if (RC->getSubClassWithSubReg(SubIdx) != RC)
continue;
// Build list of (Super, Sub) pairs for this SubIdx.
SSPairs.clear();
for (CodeGenRegister::Set::const_iterator RI = RC->getMembers().begin(),
RE = RC->getMembers().end(); RI != RE; ++RI) {
const CodeGenRegister *Super = *RI;
const CodeGenRegister *Sub = Super->getSubRegs().find(SubIdx)->second;
assert(Sub && "Missing sub-register");
SSPairs.push_back(std::make_pair(Super, Sub));
}
// Iterate over sub-register class candidates. Ignore classes created by
// this loop. They will never be useful.
for (unsigned rci = FirstSubRegRC, rce = RegClasses.size(); rci != rce;
++rci) {
CodeGenRegisterClass *SubRC = RegClasses[rci];
// Compute the subset of RC that maps into SubRC.
CodeGenRegister::Set SubSet;
for (unsigned i = 0, e = SSPairs.size(); i != e; ++i)
if (SubRC->contains(SSPairs[i].second))
SubSet.insert(SSPairs[i].first);
if (SubSet.empty())
continue;
// RC injects completely into SubRC.
if (SubSet.size() == SSPairs.size()) {
SubRC->addSuperRegClass(SubIdx, RC);
continue;
}
// Only a subset of RC maps into SubRC. Make sure it is represented by a
// class.
getOrCreateSubClass(RC, &SubSet, RC->getName() +
"_with_" + SubIdx->getName() +
"_in_" + SubRC->getName());
}
}
}