Hi!
As discussed in the PR, this patch, originally posted for PR42728,
makes sure the shortcut in all_uses_available_at is used on the same insns
in between -g and -g0, it is the second time a -fcompare-debug failure
resulted from NEXT_INSN being something different with -g, so IMHO it is
desirable to commit this.
Bootstrapped/regtested on x86_64-linux and i686-linux, and in the PR
Uros wrote he bootstrapped/regtested it on alphaev8-linux. Ok for trunk?
Then the PR discussed what to do with the remaining issues, any feedback on
that would be appreciated.
2012-08-17 Jakub Jelinek <ja...@redhat.com>
PR rtl-optimization/54294
* fwprop.c (all_uses_available_at): Ignore debug insns in between
def_insn and target_insn when checking whether the shortcut is
possible.
--- gcc/fwprop.c.jj 2012-08-15 10:55:21.000000000 +0200
+++ gcc/fwprop.c 2012-08-17 11:15:55.624101951 +0200
@@ -799,13 +799,17 @@ all_uses_available_at (rtx def_insn, rtx
df_ref *use_rec;
struct df_insn_info *insn_info = DF_INSN_INFO_GET (def_insn);
rtx def_set = single_set (def_insn);
+ rtx next;
gcc_assert (def_set);
/* If target_insn comes right after def_insn, which is very common
- for addresses, we can use a quicker test. */
- if (NEXT_INSN (def_insn) == target_insn
- && REG_P (SET_DEST (def_set)))
+ for addresses, we can use a quicker test. Ignore debug insns
+ other than target insns for this. */
+ next = NEXT_INSN (def_insn);
+ while (next && next != target_insn && DEBUG_INSN_P (next))
+ next = NEXT_INSN (next);
+ if (next == target_insn && REG_P (SET_DEST (def_set)))
{
rtx def_reg = SET_DEST (def_set);
Jakub
