On Fri, 24 Mar 2023, Jakub Jelinek wrote: > Hi! > > The PR109086 r13-6690 inline_string_cmp change to > if (diff != result) > emit_move_insn (result, diff); > regressed > FAIL: go.test/test/fixedbugs/bug207.go, -O2 -g (internal compiler error: in > emit_move_insn, at expr.cc:4224) > The problem is the Go FE doesn't mark __builtin_memcmp as pure (I'll also > send patch for that) and so result is const0_rtx when the call lost its lhs > and the above move ICEs because moving something into const0_rtx is obviously > invalid. > I think it is better not to rely on all FEs having these *cmp functions > pure anD DCE being performed. The following patch just punts from the > inline expansion in that case, so we just emit normal library call. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK. > 2023-03-24 Jakub Jelinek <ja...@redhat.com> > > PR middle-end/109258 > * builtins.cc (inline_expand_builtin_bytecmp): Return NULL_RTX early > if target == const0_rtx. > > --- gcc/builtins.cc.jj 2023-03-23 10:00:58.308100548 +0100 > +++ gcc/builtins.cc 2023-03-23 11:05:38.308135309 +0100 > @@ -7178,8 +7178,8 @@ inline_expand_builtin_bytecmp (tree exp, > bool is_ncmp = (fcode == BUILT_IN_STRNCMP || fcode == BUILT_IN_MEMCMP); > > /* Do NOT apply this inlining expansion when optimizing for size or > - optimization level below 2. */ > - if (optimize < 2 || optimize_insn_for_size_p ()) > + optimization level below 2 or if unused *cmp hasn't been DCEd. */ > + if (optimize < 2 || optimize_insn_for_size_p () || target == const0_rtx) > return NULL_RTX; > > gcc_checking_assert (fcode == BUILT_IN_STRCMP > > Jakub > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; HRB 36809 (AG Nuernberg)
