> While I support your goals, I think your approach needs some refinement.
> 
> In particular, we DO NOT want another function that starts looking at
> constant values and tries to decide, on a case by case basis, what to do
> with that value.  We need to keep the logic for that, as much as
> possible, in one small set of functions so that the compiler cannot end
> up with conflicting decisions coming from different bits of code.
> 
> So const_ok_for_split has to go.  Instead you should be using
> const_ok_for op (an existing routine) and a simple macro that
> encapsulates "optimize >= 2 && can_create_pseudo_p ()" as the gate for
> when to use a separate scratch register.
> 

Thanks for the review. Please find the patch attached that does this.
Regression tested on qemu for arm-none-linux-gnueab with no new
regressions. Bootstrapped successfully on chromebook. Is this OK for trunk?

Thanks,
Kugan


gcc/ChangeLog:

2015-04-26  Kugan Vivekanandarajah  <kuganv@linaro.org>
	    Zhenqiang Chen  <zhenqiang.chen@linaro.org>

	PR target/65768
	* config/arm/arm.h (CONST_OK_FOR_SPLIT): New macro.
	* config/arm/arm.md (subsi3, andsi3, iorsi3, xorsi3, movsi): Keep some
	 large constants in register instead of splitting them.

gcc/testsuite/ChangeLog:

2015-04-26  Kugan Vivekanandarajah  <kuganv@linaro.org>
	    Zhenqiang Chen  <zhenqiang.chen@linaro.org>

	PR target/65768
	* gcc.target/arm/maskdata.c: New test.