[PATCH] D38535: [CGP] Separate Select and Phi case in optimizeMemoryInst

[Serguei Katkov via Phabricator via llvm-commits]

skatkov created this revision.

This patch is a preparation for "Extends the scope of optimizeMemoryInst optimization".

It just a NFC to separate combining of Select and Phi nodes.


https://reviews.llvm.org/D38535

Files:
  lib/CodeGen/CodeGenPrepare.cpp


Index: lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- lib/CodeGen/CodeGenPrepare.cpp
+++ lib/CodeGen/CodeGenPrepare.cpp
@@ -3416,12 +3416,23 @@
     return false;
   }
 
+  /// \brief Defines how to combine AddrModes.
+  enum CombineType {
+    // All AddrModes are direct input of Select instruction.
+    // The new Select instruction will be created to combine the
+    // values of difference between AddrModes.
+    CombineBySelect,
+    // All AddrModes are accessible to origin Addr through only Phi nodes
+    // or there is only one AddrMode.
+    CombineByPhi
+  };
+
   /// \brief Combine the addressing modes we've collected into a single
   /// addressing mode. OnlySingleAddrMode means that only single AddrMode
   /// can be combined.
   /// \return True iff we successfully combined them or we only had one so
   /// didn't need to combine them anyway.
-  bool combineAddrModes(bool OnlySingleAddrMode) {
+  bool combineAddrModes(bool OnlySingleAddrMode, CombineType Type) {
     // If we have no AddrModes then they can't be combined.
     if (AddrModes.size() == 0)
       return false;
@@ -3439,8 +3450,27 @@
     if (AllAddrModesTrivial)
       return false;
 
-    // TODO: Combine multiple AddrModes by inserting a select or phi for the
+    // Combine multiple AddrModes by inserting a select or phi for the
     // field in which the AddrModes differ.
+    if (Type == CombineBySelect) {
+      return combineBySelect();
+    } else {
+      assert(Type == CombineByPhi && "Unexpected combine type!");
+      return combineByPhi();
+    }
+  }
+
+  bool combineBySelect() {
+    assert(AddrModes.size() == 2 && "Too many AddrModes for Select");
+    // TODO: Create select basing on AddrModes.
+    return false;
+  }
+
+  bool combineByPhi() {
+    // The first version supports only combine by base register.
+    if (DifferentField != ExtAddrMode::BaseRegField)
+      return false;
+    // TODO: Find/Create Phi node combining the difference between AddrModes.
     return false;
   }
 };
@@ -4595,7 +4625,9 @@
   // Try to combine the AddrModes we've collected. If we couldn't collect any,
   // or we have multiple but either couldn't combine them or combining them
   // wouldn't do anything useful, bail out now.
-  if (!AddrModes.combineAddrModes(OnlySingleAddrMode)) {
+  auto CombineType = CountSelectSeen ? AddressingModeCombiner::CombineBySelect
+                                     : AddressingModeCombiner::CombineByPhi;
+  if (!AddrModes.combineAddrModes(OnlySingleAddrMode, CombineType)) {
     TPT.rollback(LastKnownGood);
     return false;
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D38535.117649.patch
Type: text/x-patch
Size: 2646 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20171004/8455ab0f/attachment.bin>