From aab648a9fcf8c222ab43612915d11b093e11849d Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Wed, 12 Oct 2016 17:21:38 +0200 Subject: [PATCH] dce: Don't dead-code delete separately wrapped restores If there is a separately wrapped register restore on some path that is dead (say, control goes into an endless loop after it), then we cannot delete that restore because that would confuse the DWARF CFI (if there is another path joining). This happens with gcc.dg/torture/pr53168.c, for example. * dce.c (delete_unmarked_insns): Don't delete instructions with a REG_CFA_RESTORE note. From-SVN: r241060 --- gcc/ChangeLog | 5 +++++ gcc/dce.c | 9 +++++++++ 2 files changed, 14 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 323bf35..7793544 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2016-10-12 Segher Boessenkool + * dce.c (delete_unmarked_insns): Don't delete instructions with + a REG_CFA_RESTORE note. + +2016-10-12 Segher Boessenkool + * common.opt (-fshrink-wrap-separate): New flag. * doc/invoke.texi: Document it. * doc/tm.texi.in (Shrink-wrapping separate components): New subsection. diff --git a/gcc/dce.c b/gcc/dce.c index ea3fb00..d510287 100644 --- a/gcc/dce.c +++ b/gcc/dce.c @@ -587,6 +587,15 @@ delete_unmarked_insns (void) if (!dbg_cnt (dce)) continue; + if (crtl->shrink_wrapped_separate + && find_reg_note (insn, REG_CFA_RESTORE, NULL)) + { + if (dump_file) + fprintf (dump_file, "DCE: NOT deleting insn %d, it's a " + "callee-save restore\n", INSN_UID (insn)); + continue; + } + if (dump_file) fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn)); -- 2.7.4