DoubleToIStub can't use ip on armv6, because the ubfx impl will clobber it

src/arm/code-stubs-arm.cc

 // Copyright 2012 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 590 matching lines @@
 
 void DoubleToIStub::Generate(MacroAssembler* masm) {
   Label out_of_range, only_low, negate, done;
   Register input_reg = source();
   Register result_reg = destination();
 
   int double_offset = offset();
   // Account for saved regs if input is sp.
   if (input_reg.is(sp)) double_offset += 2 * kPointerSize;
 
-  // Immediate values for this stub fit in instructions, so it's safe to use ip.
-  Register scratch = ip;
+  Register scratch = GetRegisterThatIsNotOneOf(input_reg, result_reg);
   Register scratch_low =
       GetRegisterThatIsNotOneOf(input_reg, result_reg, scratch);
   Register scratch_high =
       GetRegisterThatIsNotOneOf(input_reg, result_reg, scratch, scratch_low);
   LowDwVfpRegister double_scratch = kScratchDoubleReg;
 
-  __ Push(scratch_high, scratch_low);
+  __ Push(scratch, scratch_high, scratch_low);

[rmcilroy, 2014/01/14 14:50:20]

Please move 'scratch' to the end of the arguments i.e.:
  __ Push(scratch_high, scratch_low, scratch);
otherwise this push can't happen in a single "stm" instruction. (same with Pop
below).

[Mostyn Bramley-Moore, 2014/01/14 15:01:50]

Done.

 
   if (!skip_fastpath()) {
     // Load double input.
     __ vldr(double_scratch, MemOperand(input_reg, double_offset));
     __ vmov(scratch_low, scratch_high, double_scratch);
 
     // Do fast-path convert from double to int.
     __ vcvt_s32_f64(double_scratch.low(), double_scratch);
     __ vmov(result_reg, double_scratch.low());
 
@@ skipping 62 matching lines @@
   // scratch_high LSR 31 equals zero.
   // New result = (result eor 0) + 0 = result.
   // If the input was negative, we have to negate the result.
   // Input_high ASR 31 equals 0xffffffff and scratch_high LSR 31 equals 1.
   // New result = (result eor 0xffffffff) + 1 = 0 - result.
   __ eor(result_reg, result_reg, Operand(scratch_high, ASR, 31));
   __ add(result_reg, result_reg, Operand(scratch_high, LSR, 31));
 
   __ bind(&done);
 
-  __ Pop(scratch_high, scratch_low);
+  __ Pop(scratch, scratch_high, scratch_low);
   __ Ret();
 }
 
 
 void WriteInt32ToHeapNumberStub::GenerateFixedRegStubsAheadOfTime(
     Isolate* isolate) {
   WriteInt32ToHeapNumberStub stub1(r1, r0, r2);
   WriteInt32ToHeapNumberStub stub2(r2, r0, r3);
   stub1.GetCode(isolate);
   stub2.GetCode(isolate);
@@ skipping 5087 matching lines @@
   __ bind(&fast_elements_case);
   GenerateCase(masm, FAST_ELEMENTS);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM