enhance the new isel to use SelectNodeTo for most patterns,

even some the old isel didn't.  There are several parts of
this that make me feel dirty, but it's no worse than the
old isel.  I'll clean up the parts I can do without ripping
out the old one next.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97415 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 65 insertions, 8 deletions

diff --git a/utils/TableGen/DAGISelMatcherOpt.cpp b/utils/TableGen/DAGISelMatcherOpt.cpp
index 12c4c1b..2ea178f 100644
--- a/utils/TableGen/DAGISelMatcherOpt.cpp
+++ b/utils/TableGen/DAGISelMatcherOpt.cpp
@@ -13,6 +13,7 @@
 
 #define DEBUG_TYPE "isel-opt"
 #include "DAGISelMatcher.h"
+#include "CodeGenDAGPatterns.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -21,7 +22,8 @@ using namespace llvm;
 
 /// ContractNodes - Turn multiple matcher node patterns like 'MoveChild+Record'
 /// into single compound nodes like RecordChild.
-static void ContractNodes(OwningPtr<Matcher> &MatcherPtr) {
+static void ContractNodes(OwningPtr<Matcher> &MatcherPtr,
+                          const CodeGenDAGPatterns &CGP) {
   // If we reached the end of the chain, we're done.
   Matcher *N = MatcherPtr.get();
   if (N == 0) return;
@@ -30,7 +32,7 @@ static void ContractNodes(OwningPtr<Matcher> &MatcherPtr) {
   if (ScopeMatcher *Scope = dyn_cast<ScopeMatcher>(N)) {
     for (unsigned i = 0, e = Scope->getNumChildren(); i != e; ++i) {
       OwningPtr<Matcher> Child(Scope->takeChild(i));
-      ContractNodes(Child);
+      ContractNodes(Child, CGP);
       Scope->resetChild(i, Child.take());
     }
     return;
@@ -52,7 +54,7 @@ static void ContractNodes(OwningPtr<Matcher> &MatcherPtr) {
       MatcherPtr.reset(New);
       // Remove the old one.
       MC->setNext(MC->getNext()->takeNext());
-      return ContractNodes(MatcherPtr);
+      return ContractNodes(MatcherPtr, CGP);
     }
   }
   
@@ -61,17 +63,69 @@ static void ContractNodes(OwningPtr<Matcher> &MatcherPtr) {
     if (MoveParentMatcher *MP = 
           dyn_cast<MoveParentMatcher>(MC->getNext())) {
       MatcherPtr.reset(MP->takeNext());
-      return ContractNodes(MatcherPtr);
+      return ContractNodes(MatcherPtr, CGP);
     }
   
   // Turn EmitNode->CompleteMatch into SelectNodeTo if we can.
   if (EmitNodeMatcher *EN = dyn_cast<EmitNodeMatcher>(N))
     if (CompleteMatchMatcher *CM =
           dyn_cast<CompleteMatchMatcher>(EN->getNext())) {
-      (void)CM;
+      // We can only use SelectNodeTo if the result values match up.
+      unsigned RootResultFirst = EN->getFirstResultSlot();
+      bool ResultsMatch = true;
+      for (unsigned i = 0, e = CM->getNumResults(); i != e; ++i)
+        if (CM->getResult(i) != RootResultFirst+i)
+          ResultsMatch = false;
+      
+      // If the selected node defines a subset of the flag/chain results, we
+      // can't use SelectNodeTo.  For example, we can't use SelectNodeTo if the
+      // matched pattern has a chain but the root node doesn't.
+      const PatternToMatch &Pattern = CM->getPattern();
+      
+      if (!EN->hasChain() &&
+          Pattern.getSrcPattern()->NodeHasProperty(SDNPHasChain, CGP))
+        ResultsMatch = false;
+
+      // If the matched node has a flag and the output root doesn't, we can't
+      // use SelectNodeTo.
+      //
+      // NOTE: Strictly speaking, we don't have to check for the flag here
+      // because the code in the pattern generator doesn't handle it right.  We
+      // do it anyway for thoroughness.
+      if (!EN->hasFlag() &&
+          Pattern.getSrcPattern()->NodeHasProperty(SDNPOutFlag, CGP))
+        ResultsMatch = false;
+      
+      
+      // If the root result node defines more results than the source root node
+      // *and* has a chain or flag input, then we can't match it because it
+      // would end up replacing the extra result with the chain/flag.
+#if 0
+      if ((EN->hasFlag() || EN->hasChain()) &&
+          EN->getNumNonChainFlagVTs() > ... need to get no results reliably ...)
+        ResultMatch = false;
+#endif
+          
+      if (ResultsMatch) {
+        const SmallVectorImpl<MVT::SimpleValueType> &VTs = EN->getVTList();
+        const SmallVectorImpl<unsigned> &Operands = EN->getOperandList();
+        MatcherPtr.reset(new SelectNodeToMatcher(EN->getOpcodeName(),
+                                                 &VTs[0], VTs.size(),
+                                               Operands.data(), Operands.size(),
+                                                 EN->hasChain(), EN->hasFlag(),
+                                                 EN->hasMemRefs(),
+                                                 EN->getNumFixedArityOperands(),
+                                                 Pattern));
+        return;
+      }
+
+      // FIXME: Handle OPC_MarkFlagResults.
+      
+      // FIXME2: Kill off all the SelectionDAG::SelectNodeTo and getMachineNode
+      // variants.  Call MorphNodeTo instead of SelectNodeTo.
     }
   
-  ContractNodes(N->getNextPtr());
+  ContractNodes(N->getNextPtr(), CGP);
 }
 
 /// SinkPatternPredicates - Pattern predicates can be checked at any level of
@@ -253,6 +307,8 @@ static void FactorNodes(OwningPtr<Matcher> &MatcherPtr) {
 
   // Reassemble a new Scope node.
   assert(!NewOptionsToMatch.empty() && "where'd all our children go?");
+  if (NewOptionsToMatch.empty())
+    MatcherPtr.reset(0);
   if (NewOptionsToMatch.size() == 1)
     MatcherPtr.reset(NewOptionsToMatch[0]);
   else {
@@ -262,9 +318,10 @@ static void FactorNodes(OwningPtr<Matcher> &MatcherPtr) {
   }
 }
 
-Matcher *llvm::OptimizeMatcher(Matcher *TheMatcher) {
+Matcher *llvm::OptimizeMatcher(Matcher *TheMatcher,
+                               const CodeGenDAGPatterns &CGP) {
   OwningPtr<Matcher> MatcherPtr(TheMatcher);
-  ContractNodes(MatcherPtr);
+  ContractNodes(MatcherPtr, CGP);
   SinkPatternPredicates(MatcherPtr);
   FactorNodes(MatcherPtr);
   return MatcherPtr.take();