[TargetLowering] Move shouldFoldShiftPairToMask next to preferShiftsToClearExtremeBit...

As discussed on PR41359, we're probably going to keep both of these but we need to make it more explicit how they complement each other.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358071 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/TargetLowering.h b/include/llvm/CodeGen/TargetLowering.h
index 47ba76cbfdd5e72385b8d94b68be3b917e573694..a5e41962a12b405236c8a466246ded47e2cccc01 100644 (file)
--- a/include/llvm/CodeGen/TargetLowering.h
+++ b/include/llvm/CodeGen/TargetLowering.h
@@ -534,6 +534,15 @@ public:
     return false;
   }
 
+  /// Return true if it is profitable to fold a pair of shifts into a mask.
+  /// This is usually true on most targets. But some targets, like Thumb1,
+  /// have immediate shift instructions, but no immediate "and" instruction;
+  /// this makes the fold unprofitable.
+  virtual bool shouldFoldShiftPairToMask(const SDNode *N,
+                                         CombineLevel Level) const {
+    return true;
+  }
+
   /// Should we tranform the IR-optimal check for whether given truncation
   /// down into KeptBits would be truncating or not:
   ///   (add %x, (1 << (KeptBits-1))) srccond (1 << KeptBits)
@@ -3138,15 +3147,6 @@ public:
     return true;
   }
 
-  /// Return true if it is profitable to fold a pair of shifts into a mask.
-  /// This is usually true on most targets. But some targets, like Thumb1,
-  /// have immediate shift instructions, but no immediate "and" instruction;
-  /// this makes the fold unprofitable.
-  virtual bool shouldFoldShiftPairToMask(const SDNode *N,
-                                         CombineLevel Level) const {
-    return true;
-  }
-
   // Return true if it is profitable to combine a BUILD_VECTOR with a stride-pattern
   // to a shuffle and a truncate.
   // Example of such a combine: