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linux/arch/hexagon
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Nathan Chancellor d7205a72ac hexagon: Disable constant extender optimization for LLVM prior to 19.1.0 
commit aef25be35d upstream.

The Hexagon-specific constant extender optimization in LLVM may crash on
Linux kernel code [1], such as fs/bcache/btree_io.c after
commit 32ed4a620c ("bcachefs: Btree path tracepoints") in 6.12:

  clang: llvm/lib/Target/Hexagon/HexagonConstExtenders.cpp:745: bool (anonymous namespace)::HexagonConstExtenders::ExtRoot::operator<(const HCE::ExtRoot &) const: Assertion `ThisB->getParent() == OtherB->getParent()' failed.
  Stack dump:
  0.      Program arguments: clang --target=hexagon-linux-musl ... fs/bcachefs/btree_io.c
  1.      <eof> parser at end of file
  2.      Code generation
  3.      Running pass 'Function Pass Manager' on module 'fs/bcachefs/btree_io.c'.
  4.      Running pass 'Hexagon constant-extender optimization' on function '@__btree_node_lock_nopath'

Without assertions enabled, there is just a hang during compilation.

This has been resolved in LLVM main (20.0.0) [2] and backported to LLVM
19.1.0 but the kernel supports LLVM 13.0.1 and newer, so disable the
constant expander optimization using the '-mllvm' option when using a
toolchain that is not fixed.

Cc: stable@vger.kernel.org
Link: https://github.com/llvm/llvm-project/issues/99714 [1]
Link: 68df06a0b2 [2]
Link: 2ab8d93061 [3]
Reviewed-by: Brian Cain <bcain@quicinc.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-12-27 13:52:56 +01:00
..
configs Merge branch 'akpm' (patches from Andrew) 2021-05-07 00:34:51 -07:00
include mm: remove kern_addr_valid() completely 2024-11-08 16:26:39 +01:00
kernel hexagon: fix fadvise64_64 calling conventions 2024-07-05 09:31:57 +02:00
lib hexagon: export raw I/O routines for modules 2021-11-20 10:35:54 -08:00
mm mm/fault: convert remaining simple cases to lock_mm_and_find_vma() 2023-07-01 13:16:25 +02:00
Kbuild hexagon: move core-y in arch/hexagon/Makefile to arch/hexagon/Kbuild 2021-05-26 23:11:47 +09:00
Kconfig mm/fault: convert remaining simple cases to lock_mm_and_find_vma() 2023-07-01 13:16:25 +02:00
Kconfig.debug treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile hexagon: Disable constant extender optimization for LLVM prior to 19.1.0 2024-12-27 13:52:56 +01:00