[llvm-commits] [llvm] r99795 - /llvm/trunk/utils/TableGen/DAGISelEmitter.cpp
Chris Lattner
sabre at nondot.org
Sun Mar 28 18:56:19 PDT 2010
Author: lattner
Date: Sun Mar 28 20:56:19 2010
New Revision: 99795
URL: http://llvm.org/viewvc/llvm-project?rev=99795&view=rev
Log:
Check in a (disabled) failed attempt to improve the ordering of
patterns within the generated matcher. This works great except
that the sort fails because the relation defined isn't
transitive. I have a much simpler solution coming next, but want
to archive the code.
Modified:
llvm/trunk/utils/TableGen/DAGISelEmitter.cpp
Modified: llvm/trunk/utils/TableGen/DAGISelEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/DAGISelEmitter.cpp?rev=99795&r1=99794&r2=99795&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/DAGISelEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/DAGISelEmitter.cpp Sun Mar 28 20:56:19 2010
@@ -102,6 +102,106 @@
OS << "\n\n";
}
+/// CouldMatchSameInput - Return true if it is possible for these two patterns
+/// to match the same input. For example, (add reg, reg) and
+/// (add reg, (mul ...)) could both match the same input. Where this is
+/// conservative, it falls back to returning true.
+static bool CouldMatchSameInput(const TreePatternNode *N1,
+ const TreePatternNode *N2) {
+ // If the types of the two nodes differ, they can't match the same thing.
+ if (N1->getNumTypes() != N2->getNumTypes()) return false;
+ for (unsigned i = 0, e = N1->getNumTypes(); i != e; ++i)
+ if (N1->getType(i) != N2->getType(i))
+ return false;
+
+ // Handle the case when at least one is a leaf.
+ if (N1->isLeaf()) {
+ if (N2->isLeaf()) {
+ // Handle leaf/leaf cases. Register operands can match just about
+ // anything, so we can only disambiguate a few things here.
+
+ // If both operands are leaf integer nodes with different values, they
+ // can't match the same thing.
+ if (IntInit *II1 = dynamic_cast<IntInit*>(N1->getLeafValue()))
+ if (IntInit *II2 = dynamic_cast<IntInit*>(N2->getLeafValue()))
+ return II1->getValue() == II2->getValue();
+
+ DefInit *DI1 = dynamic_cast<DefInit*>(N1->getLeafValue());
+ DefInit *DI2 = dynamic_cast<DefInit*>(N2->getLeafValue());
+ if (DI1 != 0 && DI2 != 0) {
+ if (DI1->getDef()->isSubClassOf("ValueType") &&
+ DI2->getDef()->isSubClassOf("ValueType"))
+ return DI1 == DI2;
+ if (DI1->getDef()->isSubClassOf("CondCode") &&
+ DI2->getDef()->isSubClassOf("CondCode"))
+ return DI1 == DI2;
+ }
+
+ // TODO: Regclass cannot match a condcode etc.
+
+ // Otherwise, complex pattern could match anything, so just return a
+ // conservative response.
+ return true;
+ }
+
+ // Conservatively return true. (imm) could match "7" for example, and GPR
+ // can match anything.
+ // TODO: could handle (add ...) != "1" if we cared.
+ return true;
+ }
+
+ // If N2 is a leaf and N1 isn't, check the other way.
+ if (N2->isLeaf())
+ return CouldMatchSameInput(N2, N1);
+
+ // Now we know neither node is a leaf. If the two patterns have different
+ // number of children or different operators, they can't both match.
+ Record *Op1 = N1->getOperator(), *Op2 = N1->getOperator();
+
+ if (Op1 != Op2 || N1->getNumChildren() != N2->getNumChildren())
+ return false;
+
+ // If a child prevents the two patterns from matching, use that.
+ for (unsigned i = 0, e = N1->getNumChildren(); i != e; ++i)
+ if (!CouldMatchSameInput(N1->getChild(i), N2->getChild(i)))
+ return false;
+
+ // Otherwise, it looks like they could both match the same thing.
+ return true;
+}
+
+/// GetSourceMatchPreferenceOrdering - The two input patterns are guaranteed to
+/// not match the same input. Decide which pattern we'd prefer to match first
+/// in order to reduce compile time. This sorting predicate is used to improve
+/// compile time so that we try to match scalar operations before vector
+/// operations since scalar operations are much more common in practice.
+///
+/// This returns -1 if we prefer to match N1 before N2, 1 if we prefer to match
+/// N2 before N1 or 0 if no preference.
+///
+static int GetSourceMatchPreferenceOrdering(const TreePatternNode *N1,
+ const TreePatternNode *N2) {
+ // The primary thing we sort on here is to get ints before floats and scalars
+ // before vectors.
+ for (unsigned i = 0, e = std::min(N1->getNumTypes(), N2->getNumTypes());
+ i != e; ++i)
+ if (N1->getType(i) != N2->getType(i)) {
+ MVT::SimpleValueType V1 = N1->getType(i), V2 = N2->getType(i);
+ if (MVT(V1).isVector() != MVT(V2).isVector())
+ return MVT(V1).isVector() ? 1 : -1;
+
+ if (MVT(V1).isFloatingPoint() != MVT(V2).isFloatingPoint())
+ return MVT(V1).isFloatingPoint() ? 1 : -1;
+ }
+
+ for (unsigned i = 0, e = std::min(N1->getNumChildren(), N2->getNumChildren());
+ i != e; ++i)
+ if (int Res = GetSourceMatchPreferenceOrdering(N1->getChild(i),
+ N2->getChild(i)))
+ return Res;
+ return 0;
+}
+
namespace {
// PatternSortingPredicate - return true if we prefer to match LHS before RHS.
@@ -112,6 +212,28 @@
CodeGenDAGPatterns &CGP;
bool operator()(const PatternToMatch *LHS, const PatternToMatch *RHS) {
+ const TreePatternNode *LHSSrc = LHS->getSrcPattern();
+ const TreePatternNode *RHSSrc = RHS->getSrcPattern();
+
+ // If the patterns are guaranteed to not match at the same time and we
+ // prefer to match one before the other (for compile time reasons) use this
+ // preference as our discriminator.
+ if (0 && !CouldMatchSameInput(LHSSrc, RHSSrc)) {
+ int Ordering = GetSourceMatchPreferenceOrdering(LHSSrc, RHSSrc);
+ if (Ordering != 0) {
+ if (Ordering == -1) {
+ errs() << "SORT: " << *LHSSrc << "\n";
+ errs() << "NEXT: " << *RHSSrc << "\n\n";
+ } else {
+ errs() << "SORT: " << *RHSSrc << "\n";
+ errs() << "NEXT: " << *LHSSrc << "\n\n";
+ }
+ }
+
+ if (Ordering == -1) return true;
+ if (Ordering == 1) return false;
+ }
+
// Otherwise, if the patterns might both match, sort based on complexity,
// which means that we prefer to match patterns that cover more nodes in the
// input over nodes that cover fewer.
@@ -167,8 +289,7 @@
// We want to process the matches in order of minimal cost. Sort the patterns
// so the least cost one is at the start.
- std::stable_sort(Patterns.begin(), Patterns.end(),
- PatternSortingPredicate(CGP));
+ std::sort(Patterns.begin(), Patterns.end(), PatternSortingPredicate(CGP));
// Convert each variant of each pattern into a Matcher.
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