implement a simple proof-of-concept optimization for
the new isel: fold movechild+record+moveparent into a
single recordchild N node. This shrinks the X86 table
from 125443 to 117502 bytes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97031 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/DAGISelMatcherOpt.cpp b/utils/TableGen/DAGISelMatcherOpt.cpp
index 7859f36..d365820 100644
--- a/utils/TableGen/DAGISelMatcherOpt.cpp
+++ b/utils/TableGen/DAGISelMatcherOpt.cpp
@@ -14,6 +14,35 @@
#include "DAGISelMatcher.h"
using namespace llvm;
-void llvm::OptimizeMatcher(const MatcherNode *Matcher) {
- // Nothing yet.
+
+static void FormRecordChildNodes(OwningPtr<MatcherNode> &Matcher) {
+ // If we reached the end of the chain, we're done.
+ MatcherNode *N = Matcher.get();
+ if (N == 0) return;
+
+ // If we have a push node, walk down both edges.
+ if (PushMatcherNode *Push = dyn_cast<PushMatcherNode>(N))
+ FormRecordChildNodes(Push->getFailurePtr());
+
+ // If we found a movechild node, check to see if our pattern matches.
+ if (MoveChildMatcherNode *MC = dyn_cast<MoveChildMatcherNode>(N)) {
+ if (RecordMatcherNode *RM = dyn_cast<RecordMatcherNode>(MC->getNext()))
+ if (MoveParentMatcherNode *MP =
+ dyn_cast<MoveParentMatcherNode>(RM->getNext())) {
+ MatcherNode *New
+ = new RecordChildMatcherNode(MC->getChildNo(), RM->getWhatFor());
+ New->setNext(MP->takeNext());
+ Matcher.reset(New);
+ return FormRecordChildNodes(Matcher);
+ }
+ }
+
+ FormRecordChildNodes(N->getNextPtr());
+}
+
+
+MatcherNode *llvm::OptimizeMatcher(MatcherNode *Matcher) {
+ OwningPtr<MatcherNode> MatcherPtr(Matcher);
+ FormRecordChildNodes(MatcherPtr);
+ return MatcherPtr.take();
}