Change the utils WhichPowerOf2 function to use a simpler algorithm.

src/arm/macro-assembler-arm.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 202 matching lines @@
 
 void MacroAssembler::Move(Register dst, Register src) {
   if (!dst.is(src)) {
     mov(dst, src);
   }
 }
 
 
 void MacroAssembler::And(Register dst, Register src1, const Operand& src2,
                          Condition cond) {
-  if (!CpuFeatures::IsSupported(ARMv7) || src2.is_single_instruction()) {
+  if (!src2.is_reg() &&
+      !src2.must_use_constant_pool() &&
+      src2.immediate() == 0) {
+    mov(dst, Operand(0, RelocInfo::NONE), LeaveCC, cond);
+
+  } else if (!src2.is_single_instruction() &&
+             !src2.must_use_constant_pool() &&
+             CpuFeatures::IsSupported(ARMv7) &&
+             IsPowerOf2(src2.immediate() + 1)) {
+    ubfx(dst, src1, 0, WhichPowerOf2(src2.immediate() + 1), cond);
+
+  } else {
     and_(dst, src1, src2, LeaveCC, cond);
-    return;
   }
-  int32_t immediate = src2.immediate();
-  if (immediate == 0) {
-    mov(dst, Operand(0, RelocInfo::NONE), LeaveCC, cond);
-    return;
-  }
-  if (IsPowerOf2(immediate + 1) && ((immediate & 1) != 0)) {
-    ubfx(dst, src1, 0, WhichPowerOf2(immediate + 1), cond);
-    return;
-  }
-  and_(dst, src1, src2, LeaveCC, cond);
 }
 
 
 void MacroAssembler::Ubfx(Register dst, Register src1, int lsb, int width,
                           Condition cond) {
   ASSERT(lsb < 32);
   if (!CpuFeatures::IsSupported(ARMv7)) {
     int mask = (1 << (width + lsb)) - 1 - ((1 << lsb) - 1);
     and_(dst, src1, Operand(mask), LeaveCC, cond);
     if (lsb != 0) {
@@ skipping 1728 matching lines @@
 
 void CodePatcher::Emit(Address addr) {
   masm()->emit(reinterpret_cast<Instr>(addr));
 }
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM