On 14/04/15 20:10, Ramana Radhakrishnan wrote:
On Tue, Apr 14, 2015 at 1:37 PM, Kyrill Tkachov <kyrylo.tkac...@arm.com> wrote:
Hi all,
The load/store-multiple expanders reject a number of registers outside of
[2-14]
but the arm_gen_{load,store}_multiple functions that they called down to
have an even
stricter restriction of <= MAX_LDM_STM_OPS that is <= 4. If load_multiple
was called with
a number of regs larger than 4 the assert would trigger and we'd ICE.
This patch fixes that possibility by FAILing in expansion if the number of
requested
regs is > MAX_LDM_STM_OPS.
The reason we never hit this currently is that the load,store_multiple
standard names are
only used in a single place in expr.c to load the argument registers from to
a function call.
By a happy coincidence for arm the number of argument registers is 4 so we
never exceed that.
The arm backend never calls the load,store_multiple expanders directly but
rather the
arm_gen* functions and it makes sure that they're never called with anything
> MAX_LDM_STM_OPS.
I hit this issue only due to a buggy change I made to expr.c that ended up
requesting a
load_multiple of 5 registers which the expander should have rejected but it
didn't,
causing an ICE.
If we add more uses of load/store_multiple in the midend this issue will be
a loaded gun.
Bootstrapped and tested on arm-none-linux-gnueabihf.
Ok for trunk?
Whoops ! Good catch.
Ok.
Thanks, I've committed this with r222357.
Kyrill
Ramana
Thanks,
Kyrill
2015-04-14 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* config/arm/arm.md (load_multiple): Reject operand 2 greater than
MAX_LDM_STM_OPS.
(store_multiple): Likewise.
