Align the stack correctly on ARM on calls to fp operation helpers.

src/arm/codegen-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 5043 matching lines @@
   __ bind(&finished_loading_r1);
 
   __ bind(&do_the_call);
   // r0: Left value (least significant part of mantissa).
   // r1: Left value (sign, exponent, top of mantissa).
   // r2: Right value (least significant part of mantissa).
   // r3: Right value (sign, exponent, top of mantissa).
   // r5: Address of heap number for result.
   __ push(lr);   // For later.
   __ push(r5);   // Address of heap number that is answer.
+  __ AlignStack(0);
   // Call C routine that may not cause GC or other trouble.
   __ mov(r5, Operand(ExternalReference::double_fp_operation(operation)));
   __ Call(r5);
+  __ pop(r4);  // Address of heap number.
+  __ cmp(r4, Operand(Smi::FromInt(0)));
+  __ pop(r4, eq);  // Conditional pop instruction to get rid of alignment push.
   // Store answer in the overwritable heap number.
-  __ pop(r4);
 #if !defined(USE_ARM_EABI)
   // Double returned in fp coprocessor register 0 and 1, encoded as register
   // cr8.  Offsets must be divisible by 4 for coprocessor so we need to
   // substract the tag from r4.
   __ sub(r5, r4, Operand(kHeapObjectTag));
   __ stc(p1, cr8, MemOperand(r5, HeapNumber::kValueOffset));
 #else
   // Double returned in registers 0 and 1.
   __ str(r0, FieldMemOperand(r4, HeapNumber::kValueOffset));
   __ str(r1, FieldMemOperand(r4, HeapNumber::kValueOffset + 4));
@@ skipping 1174 matching lines @@
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) >> 28 < (1 << 15));
   return (static_cast<unsigned>(cc_) >> 27) | (strict_ ? 1 : 0);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal