Jeffrey Law <[email protected]> writes: > On 8/14/2026 1:29 PM, Matt Turner wrote: >> Alpha encodes the rounding mode in the instruction itself, so honoring a >> rounding mode chosen at run time requires the /d qualifier, which takes the >> mode from the FPCR. alpha_fprm defaulted to ALPHA_FPRM_NORM and was only >> ever changed by an explicit -mfp-rounding-mode, so -frounding-math emitted >> statically rounded instructions and fesetround was silently ignored. >> >> Default alpha_fprm to ALPHA_FPRM_DYN when -frounding-math is in effect and >> -mfp-rounding-mode was not given, leaving both ordinary code generation and >> an explicit -mfp-rounding-mode unaffected. The VAX floating-point >> instructions have no dynamic rounding qualifier, so -mfloat-vax keeps the >> static default. >> >> This fixes the execution failures of >> gcc.dg/torture/fp-uint64-convert-double-1.c, >> fp-uint64-convert-double-2.c and fp-double-convert-float-1.c. >> >> gcc/ChangeLog: >> >> * config/alpha/alpha.cc (alpha_option_override): Set alpha_fprm to >> ALPHA_FPRM_DYN when flag_rounding_math is set, -mfp-rounding-mode >> was not given explicitly and -mfloat-vax is not in effect. >> * doc/invoke.texi (Alpha Options): Document the default rounding >> mode and its interaction with -frounding-math. > THanks. I've pushed this to the trunk as well. My last alpha build > didn't bootstrap, so something has gone weird, but I suspect it's > generic and not anything you've done. > > The last clean build I had was with: > > 7e0bb48cbb2654816ce2714de5b644f4d965d3db > > The first failed build with: > > df494ca28d75f80b4d0b4e0b93b5d23d2092131a > > The failure mode is an ICE in the gimple threader: > during GIMPLE pass: thread > ../../../gcc/libcpp/lex.cc: In function 'void _cpp_clean_line(cpp_reader*)': > ../../../gcc/libcpp/lex.cc:970:1: internal compiler error: Segmentation fault > 970 | _cpp_clean_line (cpp_reader *pfile) > | ^~~~~~~~~~~~~~~ > > I haven't tried to chase it down yet. I usually let these things > simmer a bit since testing/bisecting bootstraps of qemu emulated > targets takes an absurdly long time. But if you're interested in > chasing another issue, this may be good to check.
It's https://gcc.gnu.org/PR126876 which Aldy just fixed but trunk is kind of rough at the moment, there's https://gcc.gnu.org/PR126856 too. > > jeff sam
signature.asc
Description: PGP signature
