MIPS: Use BOVC/BNVC for overflow checking on r6.

src/mips/macro-assembler-mips.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 #define V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 
 #include "src/assembler.h"
 #include "src/globals.h"
 #include "src/mips/assembler-mips.h"
@@ skipping 1167 matching lines @@
   // untagged value afterwards.
   void SmiToDoubleFPURegister(Register smi,
                               FPURegister value,
                               Register scratch1);
 
   // -------------------------------------------------------------------------
   // Overflow handling functions.
   // Usage: first call the appropriate arithmetic function, then call one of the
   // jump functions with the overflow_dst register as the second parameter.
 
-  void AdduAndCheckForOverflow(Register dst,
-                               Register left,
-                               Register right,
-                               Register overflow_dst,
-                               Register scratch = at);
-
-  void AdduAndCheckForOverflow(Register dst, Register left,
-                               const Operand& right, Register overflow_dst,
-                               Register scratch = at);
-
-  void SubuAndCheckForOverflow(Register dst,
-                               Register left,
-                               Register right,
-                               Register overflow_dst,
-                               Register scratch = at);
-
-  void SubuAndCheckForOverflow(Register dst, Register left,
-                               const Operand& right, Register overflow_dst,
-                               Register scratch = at);
-
-  void BranchOnOverflow(Label* label,
-                        Register overflow_check,
-                        BranchDelaySlot bd = PROTECT) {
-    Branch(label, lt, overflow_check, Operand(zero_reg), bd);
+  inline void AddBranchOvf(Register dst, Register left, const Operand& right,
+                           Label* overflow_label, Register scratch = at) {
+    AddBranchOvf(dst, left, right, overflow_label, nullptr, scratch);
   }
 
-  void BranchOnNoOverflow(Label* label,
-                          Register overflow_check,
-                          BranchDelaySlot bd = PROTECT) {
-    Branch(label, ge, overflow_check, Operand(zero_reg), bd);
+  inline void AddBranchNoOvf(Register dst, Register left, const Operand& right,
+                             Label* no_overflow_label, Register scratch = at) {
+    AddBranchOvf(dst, left, right, nullptr, no_overflow_label, scratch);
   }
 
-  void RetOnOverflow(Register overflow_check, BranchDelaySlot bd = PROTECT) {
-    Ret(lt, overflow_check, Operand(zero_reg), bd);
+  void AddBranchOvf(Register dst, Register left, const Operand& right,
+                    Label* overflow_label, Label* no_overflow_label,
+                    Register scratch = at);
+
+  void AddBranchOvf(Register dst, Register left, Register right,
+                    Label* overflow_label, Label* no_overflow_label,
+                    Register scratch = at);
+
+
+  inline void SubBranchOvf(Register dst, Register left, const Operand& right,
+                           Label* overflow_label, Register scratch = at) {
+    SubBranchOvf(dst, left, right, overflow_label, nullptr, scratch);
   }
 
-  void RetOnNoOverflow(Register overflow_check, BranchDelaySlot bd = PROTECT) {
-    Ret(ge, overflow_check, Operand(zero_reg), bd);
+  inline void SubBranchNoOvf(Register dst, Register left, const Operand& right,
+                             Label* no_overflow_label, Register scratch = at) {
+    SubBranchOvf(dst, left, right, nullptr, no_overflow_label, scratch);
   }
 
+  void SubBranchOvf(Register dst, Register left, const Operand& right,
+                    Label* overflow_label, Label* no_overflow_label,
+                    Register scratch = at);
+
+  void SubBranchOvf(Register dst, Register left, Register right,
+                    Label* overflow_label, Label* no_overflow_label,
+                    Register scratch = at);
+
   // -------------------------------------------------------------------------
   // Runtime calls.
 
   // See comments at the beginning of CEntryStub::Generate.
   inline void PrepareCEntryArgs(int num_args) { li(a0, num_args); }
 
   inline void PrepareCEntryFunction(const ExternalReference& ref) {
     li(a1, Operand(ref));
   }
 
@@ skipping 157 matching lines @@
                                  Register scratch,
                                  Label* not_power_of_two_or_zero);
 
   // -------------------------------------------------------------------------
   // Smi utilities.
 
   void SmiTag(Register reg) {
     Addu(reg, reg, reg);
   }
 
+  void SmiTag(Register dst, Register src) { Addu(dst, src, src); }
+
   // Test for overflow < 0: use BranchOnOverflow() or BranchOnNoOverflow().
   void SmiTagCheckOverflow(Register reg, Register overflow);
   void SmiTagCheckOverflow(Register dst, Register src, Register overflow);
 
-  void SmiTag(Register dst, Register src) {
-    Addu(dst, src, src);
+  void BranchOnOverflow(Label* label, Register overflow_check,
+                        BranchDelaySlot bd = PROTECT) {
+    Branch(label, lt, overflow_check, Operand(zero_reg), bd);
   }
 
+  void BranchOnNoOverflow(Label* label, Register overflow_check,
+                          BranchDelaySlot bd = PROTECT) {
+    Branch(label, ge, overflow_check, Operand(zero_reg), bd);
+  }
+
+
   // Try to convert int32 to smi. If the value is to large, preserve
   // the original value and jump to not_a_smi. Destroys scratch and
   // sets flags.
   void TrySmiTag(Register reg, Register scratch, Label* not_a_smi) {
     TrySmiTag(reg, reg, scratch, not_a_smi);
   }
   void TrySmiTag(Register dst,
                  Register src,
                  Register scratch,
                  Label* not_a_smi) {
@@ skipping 331 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_