On Tue, Aug 25, 2015 at 5:50 PM, Andrew Pinski <pins...@gmail.com> wrote: > On Tue, Aug 25, 2015 at 5:37 PM, Andre Vieira > <andre.simoesdiasvie...@arm.com> wrote: >> Conditional branches have a maximum range of [-1048576, 1048572]. Any >> destination further away can not be reached by these. >> To be able to have conditional branches in very large functions, we invert >> the condition and change the destination to jump over an unconditional >> branch to the original, far away, destination. >> >> gcc/ChangeLog: >> 2015-08-07 Ramana Radhakrishnan <ramana.radhakrish...@arm.com> >> Andre Vieira <andre.simoesdiasvie...@arm.com> >> >> * config/aarch64/aarch64.md (*condjump): Handle functions > 1 >> Mib. >> (*cb<optab><mode>1): Idem. >> (*tb<optab><mode>1): Idem. >> (*cb<optab><mode>1): Idem. >> * config/aarch64/iterators.md (inv_cb): New code attribute. >> (inv_tb): Idem. >> * config/aarch64/aarch64.c (aarch64_gen_far_branch): New. >> * config/aarch64/aarch64-protos.h (aarch64_gen_far_branch): New. >> >> gcc/testsuite/ChangeLog: >> 2015-08-07 Andre Vieira <andre.simoesdiasvie...@arm.com> >> >> * gcc.target/aarch64/long-branch.c: New test. > > Just a few comments about the testcase. You could improve the size > (on disk) of the testcase by using the preprocessor some more: > Something like: > #define CASE_ENTRY2 (x) CASE_ENTRY ((x)) CASE_ENTRY ((x)+1) > #define CASE_ENTRY4 (x) CASE_ENTRY2 ((x)) CASE_ENTRY2 ((x)+2+1) > #define CASE_ENTRY8 (x) CASE_ENTRY4 ((x)) CASE_ENTRY4 ((x)+4+1) > #define CASE_ENTRY16 (x) CASE_ENTRY8 ((x)) CASE_ENTRY8 ((x)+8+1) > #define CASE_ENTRY32 (x) CASE_ENTRY16 ((x)) CASE_ENTRY16 ((x)+16) > #define CASE_ENTRY64 (x) CASE_ENTRY32 ((x)) CASE_ENTRY32 ((x)+32+1) > #define CASE_ENTRY128 (x) CASE_ENTRY64 ((x)) CASE_ENTRY16 ((x)+64+1) > #define CASE_ENTRY256 (x) CASE_ENTRY128 ((x)) CASE_ENTRY128 ((x)+128+1)
I do have an off by one error but you should get the idea. Basically instead of 200 lines, we only have 9 lines (log2(256) == 8). Thanks, Andrew > > And then use > CASE_ENTRY256 (1) > > You can do the same trick to reduce the size of CASE_ENTRY too. > > Thanks, > Andrew Pinski
