[Bug target/58424] [ARM]gcc.target/arm/pr42575.c failed on arm

[amker.cheng at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58424

--- Comment #2 from bin.cheng <amker.cheng at gmail dot com> ---
Yes, It works for below combination of options:
  -mthumb -mcpu=cortex-m4
  -mthumb/-marm -march=armv7-a/-mcpu=cortex-a7
But still happens for:
  -mthumb -mcpu=cortex-m3
  -mthumb/-marm
-mcpu=cortex-a7/-mcpu=cortex-a12/-mcpu=cortex-a9/-mcpu=cortex-a15

Maybe it has something to do with the rtx cost.  I will look into it later.