Sort the patterns before adding them to the FA so that we get the

least cost matches.  This gets us from 195 -> 208 passes on the ppc codegen tests.

llvm-svn: 96747
This commit is contained in:
Chris Lattner 2010-02-21 19:22:06 +00:00
parent 23f728e995
commit fc00a4e6b8

View File

@ -141,7 +141,6 @@ struct PatternSortingPredicate {
typedef std::pair<unsigned, std::string> CodeLine;
typedef std::vector<CodeLine> CodeList;
typedef std::vector<std::pair<const PatternToMatch*, CodeList> > PatternList;
bool operator()(const std::pair<const PatternToMatch*, CodeList> &LHSPair,
const std::pair<const PatternToMatch*, CodeList> &RHSPair) {
@ -1889,6 +1888,36 @@ void DAGISelEmitter::EmitInstructionSelector(raw_ostream &OS) {
<< "}\n\n";
}
namespace {
// PatternSortingPredicate - return true if we prefer to match LHS before RHS.
// In particular, we want to match maximal patterns first and lowest cost within
// a particular complexity first.
struct PatternSortingPredicate2 {
PatternSortingPredicate2(CodeGenDAGPatterns &cgp) : CGP(cgp) {}
CodeGenDAGPatterns &CGP;
bool operator()(const PatternToMatch *LHS,
const PatternToMatch *RHS) {
unsigned LHSSize = getPatternSize(LHS->getSrcPattern(), CGP);
unsigned RHSSize = getPatternSize(RHS->getSrcPattern(), CGP);
LHSSize += LHS->getAddedComplexity();
RHSSize += RHS->getAddedComplexity();
if (LHSSize > RHSSize) return true; // LHS -> bigger -> less cost
if (LHSSize < RHSSize) return false;
// If the patterns have equal complexity, compare generated instruction cost
unsigned LHSCost = getResultPatternCost(LHS->getDstPattern(), CGP);
unsigned RHSCost = getResultPatternCost(RHS->getDstPattern(), CGP);
if (LHSCost < RHSCost) return true;
if (LHSCost > RHSCost) return false;
return getResultPatternSize(LHS->getDstPattern(), CGP) <
getResultPatternSize(RHS->getDstPattern(), CGP);
}
};
}
void DAGISelEmitter::run(raw_ostream &OS) {
EmitSourceFileHeader("DAG Instruction Selector for the " +
CGP.getTargetInfo().getName() + " target", OS);
@ -1919,11 +1948,27 @@ void DAGISelEmitter::run(raw_ostream &OS) {
#if 0
MatcherNode *Matcher = 0;
// Walk the patterns backwards, building a matcher for each and adding it to
// the matcher for the whole target.
for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(),
E = CGP.ptm_end(); I != E;) {
const PatternToMatch &Pattern = *--E;
// Add all the patterns to a temporary list so we can sort them.
std::vector<const PatternToMatch*> Patterns;
for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(), E = CGP.ptm_end();
I != E; ++I)
Patterns.push_back(&*I);
// We want to process the matches in order of minimal cost. Sort the patterns
// so the least cost one is at the start.
// FIXME: Eliminate "PatternSortingPredicate" and rename.
std::stable_sort(Patterns.begin(), Patterns.end(),
PatternSortingPredicate2(CGP));
// Walk the patterns backwards (since we append to the front of the generated
// code), building a matcher for each and adding it to the matcher for the
// whole target.
while (!Patterns.empty()) {
const PatternToMatch &Pattern = *Patterns.back();
Patterns.pop_back();
MatcherNode *N = ConvertPatternToMatcher(Pattern, CGP);
if (Matcher == 0)
@ -1933,8 +1978,8 @@ void DAGISelEmitter::run(raw_ostream &OS) {
}
// OptimizeMatcher(Matcher);
EmitMatcherTable(Matcher, OS);
//Matcher->dump();
EmitMatcherTable(Matcher, OS);
delete Matcher;
#endif
}