[llvm] 0ab1559 - [TableGen] Reorder some checks in TreePatternNode::isIsomorphicTo to speedup -gen-dag-isel for RISC-V.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2023-04-09T00:54:50-07:00
New Revision: 0ab1559a3d92aad896aebaf7912ee6789d6bef06

URL: https://github.com/llvm/llvm-project/commit/0ab1559a3d92aad896aebaf7912ee6789d6bef06
DIFF: https://github.com/llvm/llvm-project/commit/0ab1559a3d92aad896aebaf7912ee6789d6bef06.diff

LOG: [TableGen] Reorder some checks in TreePatternNode::isIsomorphicTo to speedup -gen-dag-isel for RISC-V.

Comparing types is quite expensive when hardware modes are being
used. Checking the operator first can let us detect mismatches
earlier without checking types.

Added: 
    

Modified: 
    llvm/utils/TableGen/CodeGenDAGPatterns.cpp

Removed: 
    


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diff  --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
index 6b7922e834c4..e1327c9eb18d 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -1974,7 +1974,17 @@ void TreePatternNode::dump() const {
 bool TreePatternNode::isIsomorphicTo(const TreePatternNode *N,
                                      const MultipleUseVarSet &DepVars) const {
   if (N == this) return true;
-  if (N->isLeaf() != isLeaf() || getExtTypes() != N->getExtTypes() ||
+  if (N->isLeaf() != isLeaf())
+    return false;
+
+  // Check operator of non-leaves early since it can be cheaper than checking
+  // types.
+  if (!isLeaf())
+    if (N->getOperator() != getOperator() ||
+        N->getNumChildren() != getNumChildren())
+      return false;
+
+  if (getExtTypes() != N->getExtTypes() ||
       getPredicateCalls() != N->getPredicateCalls() ||
       getTransformFn() != N->getTransformFn())
     return false;
@@ -1989,8 +1999,6 @@ bool TreePatternNode::isIsomorphicTo(const TreePatternNode *N,
     return getLeafValue() == N->getLeafValue();
   }
 
-  if (N->getOperator() != getOperator() ||
-      N->getNumChildren() != getNumChildren()) return false;
   for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
     if (!getChild(i)->isIsomorphicTo(N->getChild(i), DepVars))
       return false;