From e3c1e225d7581a15a8c1ef766ef958386b24c850 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@gmail.com>
Date: Mon, 2 May 2016 01:53:30 +0000
Subject: [PATCH] [CodeGen] Add OPC_MoveChild0-OPC_MoveChild7 opcodes to isel
 matching tables to optimize table size. Shaves about 12K off the X86 matcher
 table.

llvm-svn: 268209
---
 llvm/include/llvm/CodeGen/SelectionDAGISel.h       |  2 ++
 llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 12 ++++++++++++
 llvm/utils/TableGen/DAGISelMatcherEmitter.cpp      | 13 ++++++++++---
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/SelectionDAGISel.h b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
index 573866223999..df5bd7743dc3 100644
--- a/llvm/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/llvm/include/llvm/CodeGen/SelectionDAGISel.h
@@ -111,6 +111,8 @@ public:
     OPC_RecordMemRef,
     OPC_CaptureGlueInput,
     OPC_MoveChild,
+    OPC_MoveChild0, OPC_MoveChild1, OPC_MoveChild2, OPC_MoveChild3,
+    OPC_MoveChild4, OPC_MoveChild5, OPC_MoveChild6, OPC_MoveChild7,
     OPC_MoveParent,
     OPC_CheckSame,
     OPC_CheckChild0Same, OPC_CheckChild1Same,
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 3996645e3da9..016dd28a1790 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2971,6 +2971,18 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
       continue;
     }
 
+    case OPC_MoveChild0: case OPC_MoveChild1:
+    case OPC_MoveChild2: case OPC_MoveChild3:
+    case OPC_MoveChild4: case OPC_MoveChild5:
+    case OPC_MoveChild6: case OPC_MoveChild7: {
+      unsigned ChildNo = Opcode-OPC_MoveChild0;
+      if (ChildNo >= N.getNumOperands())
+        break;  // Match fails if out of range child #.
+      N = N.getOperand(ChildNo);
+      NodeStack.push_back(N);
+      continue;
+    }
+
     case OPC_MoveParent:
       // Pop the current node off the NodeStack.
       NodeStack.pop_back();
diff --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index 4f944beaa50b..28473996a5c8 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -247,9 +247,16 @@ EmitMatcher(const Matcher *N, unsigned Indent, unsigned CurrentIdx,
     OS << "OPC_CaptureGlueInput,\n";
     return 1;
 
-  case Matcher::MoveChild:
-    OS << "OPC_MoveChild, " << cast<MoveChildMatcher>(N)->getChildNo() << ",\n";
-    return 2;
+  case Matcher::MoveChild: {
+    const auto *MCM = cast<MoveChildMatcher>(N);
+
+    OS << "OPC_MoveChild";
+    // Handle the specialized forms.
+    if (MCM->getChildNo() >= 8)
+      OS << ", ";
+    OS << MCM->getChildNo() << ",\n";
+    return (MCM->getChildNo() >= 8) ? 2 : 1;
+  }
 
   case Matcher::MoveParent:
     OS << "OPC_MoveParent,\n";