When compiling using GNU Binutils version 2.38 (the default on Ubuntu
22.04), the assembler does not recognise the AArch64 BFC instruction
unless Armv8.2-A is enabled. This causes the scanPosLast_neon function
to fail to compile. This appears to be fixed with GNU Binutils 2.42 (the
default on Ubuntu 24.04).
The BFC instruction is an alias of BFM, so rewrite it to express with a
BFM instruction instead. This ensures that it compiles even on the older
GNU Binutils version.
---
source/common/aarch64/pixel-util.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/source/common/aarch64/pixel-util.S
b/source/common/aarch64/pixel-util.S
index e2b31e4a1..81cf17c0d 100644
--- a/source/common/aarch64/pixel-util.S
+++ b/source/common/aarch64/pixel-util.S
@@ -860,7 +860,7 @@ function PFX(scanPosLast_neon)
lsl w13, w13, w6
lsl w15, w15, w6
extr w14, w14, w13, #31
- bfc w15, #31, #1
+ bfm w15, wzr, #1, #0
cbnz w15, .Loop_spl_1
.Lpext_end:
strh w14, [x2], #2
--
2.43.0
>From 16e50f7ee8763b2bc893407e8d1699182c125df8 Mon Sep 17 00:00:00 2001
From: George Steed <[email protected]>
Date: Tue, 29 Jul 2025 10:40:00 +0100
Subject: [PATCH] AArch64: Fix scanPosLast_neon compilation with old binutils
When compiling using GNU Binutils version 2.38 (the default on Ubuntu
22.04), the assembler does not recognise the AArch64 BFC instruction
unless Armv8.2-A is enabled. This causes the scanPosLast_neon function
to fail to compile. This appears to be fixed with GNU Binutils 2.42 (the
default on Ubuntu 24.04).
The BFC instruction is an alias of BFM, so rewrite it to express with a
BFM instruction instead. This ensures that it compiles even on the older
GNU Binutils version.
---
source/common/aarch64/pixel-util.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/source/common/aarch64/pixel-util.S b/source/common/aarch64/pixel-util.S
index e2b31e4a1..81cf17c0d 100644
--- a/source/common/aarch64/pixel-util.S
+++ b/source/common/aarch64/pixel-util.S
@@ -860,7 +860,7 @@ function PFX(scanPosLast_neon)
lsl w13, w13, w6
lsl w15, w15, w6
extr w14, w14, w13, #31
- bfc w15, #31, #1
+ bfm w15, wzr, #1, #0
cbnz w15, .Loop_spl_1
.Lpext_end:
strh w14, [x2], #2
--
2.43.0
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