[PATCH 3/9] dce: Don't dead-code delete separately wrapped restores

[Segher Boessenkool]

Deleting restores (before a noreturn) that are dead confuses dwarf2cfi.


2016-06-07  Segher Boessenkool  <seg...@kernel.crashing.org>

        * dce.c (delete_unmarked_insns): Don't delete instructions with
        a REG_CFA_RESTORE note.

---
 gcc/dce.c | 9 +++++++++
 1 file changed, 9 insertions(+)

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));
 
-- 
1.9.3