On 26.09.2016 15:19, Pitchumani Sivanupandi wrote:
Attached patch for PR71676 and PR71678.PR71676 is for AVR target that generates wrong code when switch case index is more than 16 bits. Switch case index of larger than SImode are checked for out of range before 'casesi' expand. RTL expand of casesi gets index as SImode, but index is compared in HImode and ignores upper 16bits. Attached patch changes the expansion for casesi to make the index comparison in SImode and code generation accordingly. PR71678 is ICE because below pattern in 'casesi' is not recognized. (set (reg:HI 47) (minus:HI (subreg:HI (subreg:SI (reg:DI 44) 0) 0) (reg:HI 45))) Fix of PR71676 avoids the above pattern as it changes the comparison to SImode.
But this means that all comparisons are now performed in SImode which is a great performance loss for most programs which will switch on 16-bit values.
IMO we need a less intrusive (w.r.t. performance) approach. Johann
Regtested using avrtest. No regression found. If OK, could someone commit please? Is this OK for gcc-5-branch? Regards, Pitchumani gcc/ChangeLog 2016-09-26 Pitchumani Sivanupandi <[email protected]> PR target/71676 PR target/71678 * config/avr/avr.md (casesi): Change index compare to SI mode. gcc/testsuite/ChangeLog 2016-09-26 Pitchumani Sivanupandi <[email protected]> PR target/71676 PR target/71678 * gcc.target/avr/pr71676-1.c: New test. * gcc.target/avr/pr71676.c: New test. * gcc.target/avr/pr71678.c: New test.
