From: Segher Boessenkool <segher@kernel.crashing.org>
To: gcc-patches@gcc.gnu.org
Cc: jakub@redhat.com, Segher Boessenkool <segher@kernel.crashing.org>
Subject: [PATCH] combine: Don't create REG_UNUSED notes if the reg already died (PR99927)
Date: Sun, 18 Apr 2021 15:03:07 +0000 [thread overview]
Message-ID: <b412ce8e961052e6becea3bc783a53e1d5feaa0f.1618758103.git.segher@kernel.crashing.org> (raw)
If the register named in an existing REG_UNUSED note dies somewhere
between where the note used to be and I3, we should just drop it.
2021-04-21 Segher Boessenkool <segher@kernel.crashing.org>
PR rtl-optimization/99927
* combine.c (distribute_notes) [REG_UNUSED]: If the register already
is dead, just drop it.
---
Committed to trunk. This will need backports to all open branches.
Segher
gcc/combine.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/gcc/combine.c b/gcc/combine.c
index 9063a07bd009..62bf4aeaabae 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -14366,6 +14366,11 @@ distribute_notes (rtx notes, rtx_insn *from_insn, rtx_insn *i3, rtx_insn *i2,
we keep notes from i2 or i1 if they will turn into REG_DEAD
notes. */
+ /* If this register is set or clobbered between FROM_INSN and I3,
+ we should not create a note for it. */
+ if (reg_set_between_p (XEXP (note, 0), from_insn, i3))
+ break;
+
/* If this register is set or clobbered in I3, put the note there
unless there is one already. */
if (reg_set_p (XEXP (note, 0), PATTERN (i3)))
--
1.8.3.1
next reply other threads:[~2021-04-18 15:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-18 15:03 Segher Boessenkool [this message]
2021-04-18 15:24 ` Jakub Jelinek
2021-04-18 17:03 ` Segher Boessenkool
2021-04-19 17:59 ` Segher Boessenkool
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