Fixed flooring division by a power of 2, once again...

src/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 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.
 
 #include "src/v8.h"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"
 #include "src/code-stubs.h"
 #include "src/stub-cache.h"
@@ skipping 3915 matching lines @@
     __ Mov(result, Operand(dividend, ASR, shift));
     return;
   }
 
   // If the divisor is negative, we have to negate and handle edge cases.
   __ Negs(result, dividend);
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     DeoptimizeIf(eq, instr->environment());
   }
 
+  // Dividing by -1 is basically negation, unless we overflow.
+  if (divisor == -1) {
+    if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
+      DeoptimizeIf(vs, instr->environment());
+    }
+    return;
+  }
+
   // If the negation could not overflow, simply shifting is OK.
   if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
     __ Mov(result, Operand(dividend, ASR, shift));
     return;
   }
 
-  // Dividing by -1 is basically negation, unless we overflow.
-  if (divisor == -1) {
-    DeoptimizeIf(vs, instr->environment());
-    return;
-  }
-
-  __ Asr(result, dividend, shift);
+  __ Asr(result, result, shift);
   __ Csel(result, result, kMinInt / divisor, vc);
 }
 
 
 void LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) {
   Register dividend = ToRegister32(instr->dividend());
   int32_t divisor = instr->divisor();
   Register result = ToRegister32(instr->result());
   ASSERT(!AreAliased(dividend, result));
 
@@ skipping 2091 matching lines @@
   Handle<ScopeInfo> scope_info = instr->scope_info();
   __ Push(scope_info);
   __ Push(ToRegister(instr->function()));
   CallRuntime(Runtime::kHiddenPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 
 } }  // namespace v8::internal