On 01/06/16 10:02, Ramana Radhakrishnan wrote: > > > On 09/03/16 12:56, Kyrill Tkachov wrote: >> Hi all, >> >> I notice that the output code for our store exclusive patterns accesses >> unallocated memory. >> It wants to output an strexd instruction with a pair of consecutive >> registers corresponding >> to a DImode value. For that it creates the SImode top half of the DImode >> register and puts it >> into operands[3]. But the pattern only defines entries only up to >> operands[2], with no match_dup 3 >> or like that, so operands[3] should technically be out of bounds. >> >> We already have a mechanism for printing the top half of a DImode register, >> that's the 'H' output modifier. >> So this patch changes those patterns to use that, eliminating the out of >> bounds access and making >> the code a bit simpler as well. >> >> Bootstrapped and tested on arm-none-linux-gnueabihf. >> >> Ok for trunk? >> >> Thanks, >> Kyrill >> >> 2016-03-09 Kyrylo Tkachov <kyrylo.tkac...@arm.com> >> >> * config/arm/sync.md (arm_store_exclusive<mode>): >> Use 'H' output modifier on operands[2] rather than creating a new >> entry in out-of-bounds memory of the operands array. >> (arm_store_release_exclusivedi): Likewise. > > > Ok, > Ah hang on - is this safe for big-endian - remind me again why we shouldn't use 'Q' and 'R' here ?
Ramana > Thanks, > ramana >
