[TableGen][ISel] Do a better job of factoring ScopeMatchers created during creation of SwitchTypeMatcher.

Previously we were factoring when the ScopeMatcher was initially created, but it might get more Matchers added to it later. Delay factoring until we have fully created/populated the ScopeMatchers.

This reduces X86 isel tables by 154 bytes.

llvm-svn: 287520

1 files changed, 11 insertions, 3 deletions

diff --git a/llvm/utils/TableGen/DAGISelMatcherOpt.cpp b/llvm/utils/TableGen/DAGISelMatcherOpt.cpp
index ad385fac043..74370c077f8 100644
--- a/llvm/utils/TableGen/DAGISelMatcherOpt.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherOpt.cpp
@@ -414,9 +414,7 @@ static void FactorNodes(std::unique_ptr<Matcher> &MatcherPtr) {
         }
         
         Matcher *Entries[2] = { PrevMatcher, MatcherWithoutCTM };
-        std::unique_ptr<Matcher> Case(new ScopeMatcher(Entries));
-        FactorNodes(Case);
-        Cases[Entry-1].second = Case.release();
+        Cases[Entry-1].second = new ScopeMatcher(Entries);
         continue;
       }
       
@@ -424,6 +422,16 @@ static void FactorNodes(std::unique_ptr<Matcher> &MatcherPtr) {
       Cases.push_back(std::make_pair(CTMTy, MatcherWithoutCTM));
     }
     
+    // Make sure we recursively factor any scopes we may have created.
+    for (auto &M : Cases) {
+      if (ScopeMatcher *SM = dyn_cast<ScopeMatcher>(M.second)) {
+        std::unique_ptr<Matcher> Scope(SM);
+        FactorNodes(Scope);
+        M.second = Scope.release();
+        assert(M.second && "null matcher");
+      }
+    }
+
     if (Cases.size() != 1) {
       MatcherPtr.reset(new SwitchTypeMatcher(Cases));
     } else {