commit b52bbde2870e5ab5d126612961dcb3da8e5236ee
author Vladimir Marko <vmarko@google.com> Fri Feb 12 12:06:05 2016 +0000
committer Vladimir Marko <vmarko@google.com> Mon Feb 15 15:06:44 2016 +0000
tree 3a58d251d8667e7c8447199a799fecba9bd5f918
parent 1b0755299928221a1dcc5db383bf8fc378d29b60

Optimizing: Simplify consecutive type conversions.

Merge two consecutive type conversions to one if the result
of such merged conversion is guaranteed to be the same and
remove all implicit conversions, not just conversions to the
same type. Improve codegens to handle conversions from long
to integral types smaller than int.

This will make it easier to simplify `(byte) (x & 0xffL)` to
`(byte) x` where the conversion from long to byte is done by
two dex instructions, long-to-int and in int-to-byte.

Bug: 23965701
Change-Id: I833f193556671136ad2cd3f5b31cdfbc2d99c19d

compiler/optimizing/code_generator_x86_64.cc

diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 35603aa..a5c386d 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -2363,6 +2363,8 @@
   switch (result_type) {
     case Primitive::kPrimByte:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to byte is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimShort:
@@ -2381,6 +2383,8 @@
 
     case Primitive::kPrimShort:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to short is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimByte:
@@ -2458,6 +2462,8 @@
 
     case Primitive::kPrimChar:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to char is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimByte:
@@ -2552,6 +2558,8 @@
   switch (result_type) {
     case Primitive::kPrimByte:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to byte is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimShort:
@@ -2560,13 +2568,12 @@
           // Processing a Dex `int-to-byte' instruction.
           if (in.IsRegister()) {
             __ movsxb(out.AsRegister<CpuRegister>(), in.AsRegister<CpuRegister>());
-          } else if (in.IsStackSlot()) {
+          } else if (in.IsStackSlot() || in.IsDoubleStackSlot()) {
             __ movsxb(out.AsRegister<CpuRegister>(),
                       Address(CpuRegister(RSP), in.GetStackIndex()));
           } else {
-            DCHECK(in.GetConstant()->IsIntConstant());
             __ movl(out.AsRegister<CpuRegister>(),
-                    Immediate(static_cast<int8_t>(in.GetConstant()->AsIntConstant()->GetValue())));
+                    Immediate(static_cast<int8_t>(Int64FromConstant(in.GetConstant()))));
           }
           break;
 
@@ -2578,6 +2585,8 @@
 
     case Primitive::kPrimShort:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to short is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimByte:
@@ -2586,13 +2595,12 @@
           // Processing a Dex `int-to-short' instruction.
           if (in.IsRegister()) {
             __ movsxw(out.AsRegister<CpuRegister>(), in.AsRegister<CpuRegister>());
-          } else if (in.IsStackSlot()) {
+          } else if (in.IsStackSlot() || in.IsDoubleStackSlot()) {
             __ movsxw(out.AsRegister<CpuRegister>(),
                       Address(CpuRegister(RSP), in.GetStackIndex()));
           } else {
-            DCHECK(in.GetConstant()->IsIntConstant());
             __ movl(out.AsRegister<CpuRegister>(),
-                    Immediate(static_cast<int16_t>(in.GetConstant()->AsIntConstant()->GetValue())));
+                    Immediate(static_cast<int16_t>(Int64FromConstant(in.GetConstant()))));
           }
           break;
 
@@ -2735,6 +2743,8 @@
 
     case Primitive::kPrimChar:
       switch (input_type) {
+        case Primitive::kPrimLong:
+          // Type conversion from long to char is a result of code transformations.
         case Primitive::kPrimBoolean:
           // Boolean input is a result of code transformations.
         case Primitive::kPrimByte:
@@ -2743,14 +2753,12 @@
           // Processing a Dex `int-to-char' instruction.
           if (in.IsRegister()) {
             __ movzxw(out.AsRegister<CpuRegister>(), in.AsRegister<CpuRegister>());
-          } else if (in.IsStackSlot()) {
+          } else if (in.IsStackSlot() || in.IsDoubleStackSlot()) {
             __ movzxw(out.AsRegister<CpuRegister>(),
                       Address(CpuRegister(RSP), in.GetStackIndex()));
           } else {
-            DCHECK(in.GetConstant()->IsIntConstant());
             __ movl(out.AsRegister<CpuRegister>(),
-                    Immediate(static_cast<uint16_t>(
-                        in.GetConstant()->AsIntConstant()->GetValue())));
+                    Immediate(static_cast<uint16_t>(Int64FromConstant(in.GetConstant()))));
           }
           break;