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. 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.