Compiler constant handling rework

In preparation for de-optimization, reworked the constant
handling mechanism.  Also took advantage of knowledge of
constant operands (particularly for long operations).

Significant performance improvements for Mandelbrot
(~60 seconds to ~34 seconds).  Minor improvements in other
benchmarks.

The new constant handling breaks two of the existing
optimization passes: "Skip Large Method" and "Load/Store
Elimization."

I don't intend to update the large method optimization
because it will be superceeded by the upcoming interpreter/
fingerprinting mechanism.  Leaving the code in place for
now in order to compare compile-time improvements with
fingerprinting/interpret.  All related code will be deleted
when that is complete.

The load/store elimination pass needs some rework to handle
uses of multiple-register loads and stores.  It will be
updated & restored in a future CL.

Change-Id: Ia979abaf51b8ae81bbb0428031cbcea854625fac
diff --git a/src/compiler/codegen/mips/utility_mips.cc b/src/compiler/codegen/mips/utility_mips.cc
index 1e217fb..12d054c 100644
--- a/src/compiler/codegen/mips/utility_mips.cc
+++ b/src/compiler/codegen/mips/utility_mips.cc
@@ -52,17 +52,24 @@
   return res;
 }
 
-bool MipsCodegen::InexpensiveConstant(int reg, int value)
+bool MipsCodegen::InexpensiveConstantInt(int32_t value)
 {
-  bool res = false;
-  if (value == 0) {
-    res = true;
-  } else if (IsUint(16, value)) {
-    res = true;
-  } else if ((value < 0) && (value >= -32768)) {
-    res = true;
-  }
-  return res;
+  return ((value == 0) || IsUint(16, value) || ((value < 0) && (value >= -32768)));
+}
+
+bool MipsCodegen::InexpensiveConstantFloat(int32_t value)
+{
+  return false;  // TUNING
+}
+
+bool MipsCodegen::InexpensiveConstantLong(int64_t value)
+{
+  return false;  // TUNING
+}
+
+bool MipsCodegen::InexpensiveConstantDouble(int64_t value)
+{
+  return false; // TUNING
 }
 
 /*
@@ -336,12 +343,11 @@
   return NewLIR2(cu, opcode, r_dest_src1, r_src2);
 }
 
-LIR* MipsCodegen::LoadConstantValueWide(CompilationUnit *cu, int r_dest_lo, int r_dest_hi,
-                                        int val_lo, int val_hi)
+LIR* MipsCodegen::LoadConstantWide(CompilationUnit *cu, int r_dest_lo, int r_dest_hi, int64_t value)
 {
   LIR *res;
-  res = LoadConstantNoClobber(cu, r_dest_lo, val_lo);
-  LoadConstantNoClobber(cu, r_dest_hi, val_hi);
+  res = LoadConstantNoClobber(cu, r_dest_lo, Low32Bits(value));
+  LoadConstantNoClobber(cu, r_dest_hi, High32Bits(value));
   return res;
 }