From: Alex Coplan <alex.coplan@arm.com>
Date: Thu, 12 Oct 2023 16:49:20 +0000 (+0100)
Subject: reg-notes.def: Fix up description of REG_NOALIAS
X-Git-Tag: basepoints/gcc-15~5541
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f150717bd928df13642d31f010573a329b34689c;p=thirdparty%2Fgcc.git

reg-notes.def: Fix up description of REG_NOALIAS

The description of the REG_NOALIAS note in reg-notes.def isn't quite
right. It describes it as being attached to call insns, but it is
instead attached to a move insn receiving the return value from a call.

This can be seen by looking at the code in calls.cc:expand_call which
attaches the note:

  emit_move_insn (temp, valreg);

  /* The return value from a malloc-like function cannot alias
     anything else.  */
  last = get_last_insn ();
  add_reg_note (last, REG_NOALIAS, temp);

gcc/ChangeLog:

	* reg-notes.def (NOALIAS): Correct comment.
---

diff --git a/gcc/reg-notes.def b/gcc/reg-notes.def
index 1f74a605b3ef..5cbe35dfe36b 100644
--- a/gcc/reg-notes.def
+++ b/gcc/reg-notes.def
@@ -96,8 +96,9 @@ REG_NOTE (DEP_CONTROL)
    to extract the actual value.  */
 REG_NOTE (BR_PROB)
 
-/* Attached to a call insn; indicates that the call is malloc-like and
-   that the pointer returned cannot alias anything else.  */
+/* Attached to a move insn which receives the result of a call; indicates that
+   the call is malloc-like and that the pointer returned cannot alias anything
+   else.  */
 REG_NOTE (NOALIAS)
 
 /* REG_BR_PRED is attached to JUMP_INSNs.  It contains