[PATCH 6/6] memops: we can kill addresses unconditionally

From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: linux-sparse@vger.kernel.org
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: [PATCH 6/6] memops: we can kill addresses unconditionally
Date: Sun, 21 Mar 2021 18:08:22 +0100	[thread overview]
Message-ID: <20210321170822.46854-7-luc.vanoostenryck@gmail.com> (raw)
In-Reply-To: <20210321170822.46854-1-luc.vanoostenryck@gmail.com>

In rewrite_load_instruction(), if the load instruction is converted
into a phi-node, its address is then no more used and must be removed.

However, this is only done when this address is not a symbol.
This was explicitly done in the following commit because of the problem
of removing an element from the usage list while walking this list:
   602f6b6c0d41 ("Leave symbol pseudo usage intact when doing phi-node conversion.")

But currently rewrite_load_instruction() is only used during memops
simplification where the usage list is not walked.

So, kill the address' usage unconditionally.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 memops.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/memops.c b/memops.c
index 897fb6bf57fe..6d24604c2aae 100644
--- a/memops.c
+++ b/memops.c
@@ -45,9 +45,7 @@ static void rewrite_load_instruction(struct instruction *insn, struct pseudo_lis
 	goto end;
 
 complex_phi:
-	/* We leave symbol pseudos with a bogus usage list here */
-	if (insn->src->type != PSEUDO_SYM)
-		kill_use(&insn->src);
+	kill_use(&insn->src);
 	insn->opcode = OP_PHI;
 	insn->phi_list = dominators;
 
-- 
2.31.0

