https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121567
Bug ID: 121567
Summary: SH4 error: unable to find a register to spill in class
‘R0_REGS’ issue when building Python at O2/O3
Product: gcc
Version: 15.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: thomas.petazz...@free-electrons.com
Target Milestone: ---
Created attachment 62126
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62126&action=edit
Pre-processed source file
The Objects/obmalloc.c source file of Python 3.13.5 cannot be compiled for SH4
with GCC 15.2.0 (and older versions as well, but not tested since when the
issue exists) when -O2 or -O3 is used.
The attached pre-processed file allows to reproduce the issue:
$ sh4-buildroot-linux-gnu-gcc -O1 -c Objects/obmalloc.i -o blabla.o
$
Builds fine.
But:
$ sh4-buildroot-linux-gnu-gcc -O2 -c Objects/obmalloc.i -o prout.o
Objects/obmalloc.c: In function ‘_PyMem_SetDefaultAllocator’:
Objects/obmalloc.c:503:1: error: unable to find a register to spill in class
‘R0_REGS’
503 | }
| ^
Objects/obmalloc.c:503:1: error: this is the insn:
(insn 18 243 23 2 (parallel [
(set (subreg:SI (reg:QI 176) 0)
(unspec_volatile:SI [
(mem/v:QI (reg:SI 4 r4 [175]) [-1 S1 A32])
(reg:QI 7 r7 [178])
(reg:QI 6 r6 [180])
] UNSPECV_CMPXCHG_1))
(set (mem/v:QI (reg:SI 4 r4 [175]) [-1 S1 A32])
(unspec_volatile:QI [
(const_int 0 [0])
] UNSPECV_CMPXCHG_2))
(set (reg:SI 147 t)
(unspec_volatile:SI [
(const_int 0 [0])
] UNSPECV_CMPXCHG_3))
(clobber (scratch:SI))
(clobber (reg:SI 0 r0))
(clobber (reg:SI 1 r1))
]) "./Include/cpython/pyatomic_gcc.h":105:10 407
{atomic_compare_and_swapqi_soft_gusa}
(expr_list:REG_DEAD (reg:QI 6 r6 [180])
(expr_list:REG_DEAD (reg:QI 7 r7 [178])
(expr_list:REG_UNUSED (reg:QI 176)
(expr_list:REG_UNUSED (reg:SI 1 r1)
(expr_list:REG_UNUSED (reg:SI 0 r0)
(nil)))))))
Objects/obmalloc.c:503: confused by earlier errors, bailing out
