commit 93445689c714e53cabf347da4321ecf3023e926c
author Roland Levillain <rpl@google.com> Mon Oct 06 19:24:02 2014 +0100
committer Roland Levillain <rpl@google.com> Wed Oct 08 15:25:11 2014 +0100
tree 459c38b3c12b335358278b745f431e68c18d0824
parent 50940ea8fe668a80c15920d98cae228851ceb990

Fix and improve static evaluation of constant expressions.

- Fix the definition of art::HSub::Evaluate.
- Qualify Evaluate methods as OVERRIDE.
- Evaluate comparisons in a deterministic way: if a
  comparison is true, always return 1 (instead of letting
  the compiler return any non-null value).
- Better exercise static evaluation of constant expressions
  in compiler/optimizing/constant_propagation_test.cc.

Change-Id: I13d0862e5f4eba1275016fb8c3c17e9aff54408b

compiler/optimizing/nodes.h

diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 3d65366..fc5b06d 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -93,6 +93,7 @@
 
   ArenaAllocator* GetArena() const { return arena_; }
   const GrowableArray<HBasicBlock*>& GetBlocks() const { return blocks_; }
+  HBasicBlock* GetBlock(size_t id) const { return blocks_.Get(id); }
 
   HBasicBlock* GetEntryBlock() const { return entry_block_; }
   HBasicBlock* GetExitBlock() const { return exit_block_; }
@@ -1143,8 +1144,12 @@
   HEqual(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x == y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x == y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x == y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x == y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(Equal);
 
@@ -1161,8 +1166,12 @@
   HNotEqual(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x != y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x != y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x != y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x != y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(NotEqual);
 
@@ -1179,8 +1188,12 @@
   HLessThan(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x < y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x < y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x < y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x < y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(LessThan);
 
@@ -1197,8 +1210,12 @@
   HLessThanOrEqual(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x <= y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x <= y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x <= y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x <= y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(LessThanOrEqual);
 
@@ -1215,8 +1232,12 @@
   HGreaterThan(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x > y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x > y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x > y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x > y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(GreaterThan);
 
@@ -1233,8 +1254,12 @@
   HGreaterThanOrEqual(HInstruction* first, HInstruction* second)
       : HCondition(first, second) {}
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x >= y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x >= y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x >= y ? 1 : 0;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x >= y ? 1 : 0;
+  }
 
   DECLARE_INSTRUCTION(GreaterThanOrEqual);
 
@@ -1257,13 +1282,13 @@
     DCHECK_EQ(type, second->GetType());
   }
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const {
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
     return
       x == y ? 0 :
       x > y ? 1 :
       -1;
   }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const {
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
     return
       x == y ? 0 :
       x > y ? 1 :
@@ -1490,8 +1515,12 @@
 
   virtual bool IsCommutative() { return true; }
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x + y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x + y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x + y;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x + y;
+  }
 
   DECLARE_INSTRUCTION(Add);
 
@@ -1506,8 +1535,12 @@
 
   virtual bool IsCommutative() { return false; }
 
-  virtual int32_t Evaluate(int32_t x, int32_t y) const { return x + y; }
-  virtual int64_t Evaluate(int64_t x, int64_t y) const { return x + y; }
+  virtual int32_t Evaluate(int32_t x, int32_t y) const OVERRIDE {
+    return x - y;
+  }
+  virtual int64_t Evaluate(int64_t x, int64_t y) const OVERRIDE {
+    return x - y;
+  }
 
   DECLARE_INSTRUCTION(Sub);