Unlike REG_DEAD notes, REG_UNUSED notes need to be kept free of
false positives by all passes. function_info::change_insns
does this by removing all REG_UNUSED notes, and then using
add_reg_unused_notes to add notes back (or create new ones)
where appropriate.
The problem was that it called add_reg_unused_notes on the fly
while updating each instruction, which meant that the information
for later instructions in the change set wasn't up to date.
This patch does it in a separate loop instead.
gcc/
* rtl-ssa/changes.cc (function_info::apply_changes_to_insn): Remove
call to add_reg_unused_notes and instead...
(function_info::change_insns): ...use a separate loop here.
---
gcc/rtl-ssa/changes.cc | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/gcc/rtl-ssa/changes.cc b/gcc/rtl-ssa/changes.cc
index de6222ae736..c73c23c86fb 100644
--- a/gcc/rtl-ssa/changes.cc
+++ b/gcc/rtl-ssa/changes.cc
@@ -586,8 +586,6 @@ function_info::apply_changes_to_insn (insn_change &change)
insn->set_accesses (builder.finish ().begin (), num_defs, num_uses);
}
-
- add_reg_unused_notes (insn);
}
// Add a temporary placeholder instruction after AFTER.
@@ -733,9 +731,14 @@ function_info::change_insns (array_slice<insn_change *>
changes)
}
}
- // Finally apply the changes to the underlying insn_infos.
+ // Apply the changes to the underlying insn_infos.
for (insn_change *change : changes)
apply_changes_to_insn (*change);
+
+ // Now that the insns and accesses are up to date, add any REG_UNUSED notes.
+ for (insn_change *change : changes)
+ if (!change->is_deletion ())
+ add_reg_unused_notes (change->insn ());
}
// See the comment above the declaration.
--
2.25.1
