MIPS: New array bounds check elimination pass (focused on induction variables...

MIPS: New array bounds check elimination pass (focused on induction variables and bitwise operations).

Port r15866 (52e8581c)

BUG=

Review URL: https://codereview.chromium.org/20393002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15890 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -4163,6 +4163,21 @@ void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
 }
 
 
+void LCodeGen::ApplyCheckIf(Condition cc,
+                            LBoundsCheck* check,
+                            Register src1,
+                            const Operand& src2) {
+  if (FLAG_debug_code && check->hydrogen()->skip_check()) {
+    Label done;
+    __ Branch(&done, NegateCondition(cc), src1, src2);
+    __ stop("eliminated bounds check failed");
+    __ bind(&done);
+  } else {
+    DeoptimizeIf(cc, check->environment(), src1, src2);
+  }
+}
+
+
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->hydrogen()->skip_check()) return;
 
@@ -4175,13 +4190,13 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
     } else {
       __ li(at, Operand(constant_index));
     }
-    DeoptimizeIf(condition,
-                 instr->environment(),
+    ApplyCheckIf(condition,
+                 instr,
                  at,
                  Operand(ToRegister(instr->length())));
   } else {
-    DeoptimizeIf(condition,
-                 instr->environment(),
+    ApplyCheckIf(condition,
+                 instr,
                  ToRegister(instr->index()),
                  Operand(ToRegister(instr->length())));
   }

src/mips/lithium-codegen-mips.h

@@ -284,6 +284,10 @@ class LCodeGen BASE_EMBEDDED {
                     LEnvironment* environment,
                     Register src1 = zero_reg,
                     const Operand& src2 = Operand(zero_reg));
+  void ApplyCheckIf(Condition cc,
+                    LBoundsCheck* check,
+                    Register src1 = zero_reg,
+                    const Operand& src2 = Operand(zero_reg));
 
   void AddToTranslation(Translation* translation,
                         LOperand* op,