Refine CountOperation of FullCodeGen

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 27900c1eef739719ef98b0041446f83b666df6ca..66446ae2cc7f06bb578933446870e1cfbd895660 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -1567,7 +1567,8 @@ void MacroAssembler::SmiSubConstant(Register dst, Register src, Smi* constant) {
 void MacroAssembler::SmiSubConstant(Register dst,
                                     Register src,
                                     Smi* constant,
-                                    Label* on_not_smi_result,
+                                    SmiOperationExecutionMode mode,
+                                    Label* bailout_label,
                                     Label::Distance near_jump) {
   if (constant->value() == 0) {
     if (!dst.is(src)) {
@@ -1575,36 +1576,28 @@ void MacroAssembler::SmiSubConstant(Register dst,
     }
   } else if (dst.is(src)) {
     ASSERT(!dst.is(kScratchRegister));
-    if (constant->value() == Smi::kMinValue) {
-      // Subtracting min-value from any non-negative value will overflow.
-      // We test the non-negativeness before doing the subtraction.
-      testq(src, src);
-      j(not_sign, on_not_smi_result, near_jump);
-      LoadSmiConstant(kScratchRegister, constant);
-      subq(dst, kScratchRegister);
+    LoadSmiConstant(kScratchRegister, constant);
+    subq(dst, kScratchRegister);
+    if (mode.Contains(BAILOUT_ON_NO_OVERFLOW)) {
+      j(no_overflow, bailout_label, near_jump);
+      ASSERT(mode.Contains(NEED_RESERVE_SOURCES));
+      addq(dst, kScratchRegister);
+    } else if (mode.Contains(BAILOUT_ON_OVERFLOW)) {
+      if (mode.Contains(NEED_RESERVE_SOURCES)) {
+        Label done;
+        j(no_overflow, &done, Label::kNear);
+        addq(dst, kScratchRegister);
+        jmp(bailout_label, near_jump);
+        bind(&done);
+      } else {
+        // Implement this when SimSubConstant is invoked from Crankshaft.
+        UNIMPLEMENTED();  // Not used.

[danno, 2013/10/14 18:30:45]

I would feel more comfortable if you implemented this now with tests, otherwise
we could get silent failures in the future in release builds.

[haitao.feng, 2013/10/16 09:17:01]

Done.

+      }
     } else {
-      // Subtract by adding the negation.
-      LoadSmiConstant(kScratchRegister, Smi::FromInt(-constant->value()));
-      addq(kScratchRegister, dst);
-      j(overflow, on_not_smi_result, near_jump);
-      movq(dst, kScratchRegister);
+      ASSERT(mode.IsEmpty());

[danno, 2013/10/14 18:30:45]

Turn this ASSERT into a CHECK

[haitao.feng, 2013/10/16 09:17:01]

Done.

     }
   } else {
-    if (constant->value() == Smi::kMinValue) {
-      // Subtracting min-value from any non-negative value will overflow.
-      // We test the non-negativeness before doing the subtraction.
-      testq(src, src);
-      j(not_sign, on_not_smi_result, near_jump);
-      LoadSmiConstant(dst, constant);
-      // Adding and subtracting the min-value gives the same result, it only
-      // differs on the overflow bit, which we don't check here.
-      addq(dst, src);
-    } else {
-      // Subtract by adding the negation.
-      LoadSmiConstant(dst, Smi::FromInt(-(constant->value())));
-      addq(dst, src);
-      j(overflow, on_not_smi_result, near_jump);
-    }
+    UNIMPLEMENTED();  // Not used.

[danno, 2013/10/14 18:30:45]

I would feel more comfortable if you implemented this now with tests, otherwise
we could get silent failures in the future in release builds.

[haitao.feng, 2013/10/16 09:17:01]

Done.

   }
 }