On April 3, 2021 10:39:20 PM GMT+02:00, Iain Sandoe <i...@sandoe.co.uk> wrote: >Hi > >I’ve been chasing a bootstrap failure present when we use clang as >the bootstrap - and seen for GCC11 (where the requirement is C++11) >even though the same clang toolchain bootstraps GCC-10. > >The C++11 aspect turned out to be a red-herring .. the problem was >latent already, and is a long-standing regression - most likely since >the >changes for LRA. > >The patch applied is a conservative fix for GCC-11 and backporting to >the open release branches. > >During GCC-12, I plan to factor this code (since I now have a third >arch >to deal with) and continue machopic tidy up. I have a strong suspicion >that this code is actually dead with LRA (but was not removed at the >time >the change was made). However, taking it out is too risky at this >stage. > >tested across the Darwin range, >pushed to master, so far. > >——— > >This is needed on the open branches, and given that we are re-spining >10.3 - I’d like to push it there rather than tell my downstream to >apply it >after the release. > > >OK for 10.3?
Ok. Richard. >===== > >During changes made for LRA (or, perhaps, even before) we omitted >a check that the current register we are working on is a hard reg >before we tried to note its liveness. > >A stage 1 built with fsanitize=address catches this, as does any >attempt to build master with clang and -std=c++11. > >gcc/ChangeLog: > > * config/darwin.c (machopic_legitimize_pic_address): Check > that the current pic register is one of the hard reg set > before setting liveness. >--- > gcc/config/darwin.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > >diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c >index c1086a04700..5d173919ee0 100644 >--- a/gcc/config/darwin.c >+++ b/gcc/config/darwin.c >@@ -907,7 +907,7 @@ machopic_legitimize_pic_address (rtx orig, >machine_mode mode, rtx reg) > pic = reg; > } > >- if (lra_in_progress) >+ if (lra_in_progress && HARD_REGISTER_P (pic)) > df_set_regs_ever_live (REGNO (pic), true); > pic_ref = gen_rtx_PLUS (Pmode, pic, > machopic_gen_offset (XEXP (orig, 0))); >@@ -974,7 +974,8 @@ machopic_legitimize_pic_address (rtx orig, >machine_mode mode, rtx reg) > emit_move_insn (reg, pic); > pic = reg; > } >- if (lra_in_progress) >+ >+ if (lra_in_progress && HARD_REGISTER_P (pic)) > df_set_regs_ever_live (REGNO (pic), true); > pic_ref = gen_rtx_PLUS (Pmode, > pic,
