From: Richard Sandiford <richard.sandiford@arm.com>
To: jlaw@ventanamicro.com, gcc-patches@gcc.gnu.org
Cc: Richard Sandiford <richard.sandiford@arm.com>
Subject: [PATCH 2/6] rtl-ssa: Create REG_UNUSED notes after all pending changes
Date: Tue, 24 Oct 2023 11:50:02 +0100 [thread overview]
Message-ID: <20231024105006.3337671-3-richard.sandiford@arm.com> (raw)
In-Reply-To: <20231024105006.3337671-1-richard.sandiford@arm.com>
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
next prev parent reply other threads:[~2023-10-24 10:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-24 10:50 [PATCH 0/6] rtl-ssa: Various fixes needed for the late-combine pass Richard Sandiford
2023-10-24 10:50 ` [PATCH 1/6] rtl-ssa: Ensure global registers are live on exit Richard Sandiford
2023-10-24 17:21 ` Jeff Law
2023-10-24 10:50 ` Richard Sandiford [this message]
2023-10-24 17:22 ` [PATCH 2/6] rtl-ssa: Create REG_UNUSED notes after all pending changes Jeff Law
2023-10-24 10:50 ` [PATCH 3/6] rtl-ssa: Fix ICE when deleting memory clobbers Richard Sandiford
2023-10-24 17:24 ` Jeff Law
2023-10-24 10:50 ` [PATCH 4/6] rtl-ssa: Handle artifical uses of deleted defs Richard Sandiford
2023-10-24 17:26 ` Jeff Law
2023-10-24 10:50 ` [PATCH 5/6] rtl-ssa: Calculate dominance frontiers for the exit block Richard Sandiford
2023-10-24 17:28 ` Jeff Law
2023-10-24 10:50 ` [PATCH 6/6] rtl-ssa: Handle call clobbers in more places Richard Sandiford
2023-10-24 17:37 ` Jeff Law
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