From ba7cf16dbb6225d487abc602b3464db0a8b16387 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Fri, 20 Jul 2001 19:17:47 +0000
Subject: [PATCH] Header to raise and lower representation

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Optimizations/LevelChange.h | 77 ++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 include/llvm/Optimizations/LevelChange.h

diff --git a/include/llvm/Optimizations/LevelChange.h b/include/llvm/Optimizations/LevelChange.h
new file mode 100644
index 00000000000..745b893d84a
--- /dev/null
+++ b/include/llvm/Optimizations/LevelChange.h
@@ -0,0 +1,77 @@
+//===-- LevelChange.h - Functions for raising/lowering methods ---*- C++ -*--=//
+//
+// This family of functions is useful for changing the 'level' of a method.  
+// This can either be raising (converting direct addressing to use getelementptr
+// for structs and arrays), or lowering (for instruction selection).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_OPT_LEVELCHANGE_H
+#define LLVM_OPT_LEVELCHANGE_H
+
+#include "llvm/Module.h"
+#include "llvm/Method.h"
+
+namespace opt {
+  struct Level {      // Define a namespace to contain the enum
+    enum ID {    // Define an enum of levels to change into
+      Lowest,           // The lowest level: ...
+      //...
+
+      Normal,           // The level LLVM is assumed to be in
+
+      Simplified,       // Elminate silly things like unnecesary casts
+
+      StructureAccess,  // Convert pointer addressing to structure getelementptr
+                        // instructions.
+
+      ArrayAccess,      // Simple direct access through pointers is converted to
+                        // array accessors
+
+      InductionVars,    // Auxillary induction variables are eliminated by
+                        // introducing a cannonical indvar, and making all
+                        // others use it.  This creates more opportunites to
+                        // apply the previous optimizations.
+
+      Highest = InductionVars,
+    };
+  };
+
+  // DoRaiseRepresentation - Raise a method representation to a higher level.
+  // The specific features to add are specified with the ToLevel argument.
+  //
+  bool DoRaiseRepresentation(Method *M, Level::ID ToLevel);
+  bool DoRaiseRepresentation(Module *M, Level::ID ToLevel);
+  static inline bool DoRaiseRepresentation(Method *M) {
+    return DoRaiseRepresentation(M, Level::Highest);
+  }
+  bool DoRaiseRepresentation(Module *M, Level::ID ToLevel);
+  static inline bool DoRaiseRepresentation(Module *M) {
+    return DoRaiseRepresentation(M, Level::Highest);
+  }
+
+  // DoEliminateAuxillaryInductionVariables - Eliminate all aux indvars.  This
+  // is one of the transformations performed by DoRaiseRepresentation, that
+  // converts all induction variables to reference a cannonical induction
+  // variable (which starts at 0 and counts by 1).
+  //
+  bool DoEliminateAuxillaryInductionVariables(Method *M);
+  static inline bool DoEliminateAuxillaryInductionVariables(Module *M) {
+    return M->reduceApply(DoEliminateAuxillaryInductionVariables);
+  }
+
+
+  // DoLowerRepresentation - Lower a method representation to a lower level.
+  // The specific features to eliminate are specified with the ToLevel argument.
+  //
+  bool DoLowerRepresentation(Method *M, Level::ID ToLevel);
+  bool DoLowerRepresentation(Module *M, Level::ID ToLevel);
+  static inline bool DoLowerRepresentation(Module *M) {
+    return DoLowerRepresentation(M, Level::Lowest);
+  }
+  static inline bool DoLowerRepresentation(Method *M) {
+    return DoLowerRepresentation(M, Level::Lowest);
+  }
+}  // End namespace opt
+
+#endif