On ARM targets that normally support LDRD/STRD there are tuning parameters that express the preference for using these instructions over LDM/STM. However, that's only a preference and when the architecture and tuning options differ (for example, tuning for Cortex-A15 but using the ARMv5 ISA) then it is essential to ensure that the architecture also has the instructions.
R. 2013-09-18 Richard Earnshaw <rearn...@arm.com> * arm.c (arm_get_frame_offsets): Validate architecture supports LDRD/STRD before accepting the tuning preference. (arm_expand_prologue): Likewise. (arm_expand_epilogue): Likewise. Committed to trunk. A 4.8 back-port will follow. R.