https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81426
Sergei Trofimovich <slyfox at inbox dot ru> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |slyfox at inbox dot ru
--- Comment #7 from Sergei Trofimovich <slyfox at inbox dot ru> ---
Not sure if it's the same bug or not, but I get the same error building GHC for
SH4. Reproducible on gcc-master and on gcc-9.2.0.
Here is the minimal reproducer extracted by creduce:
$ cat bug.c
/*
works:
$ sh4-unknown-linux-gnu-gcc -o bug.o -c bug.c
fails:
$ sh4-unknown-linux-gnu-gcc -O -o bug.o -c bug.c
error:
error: unable to find a register to spill in class 'R0_REGS'
*/
inline int a(char *b, char c) { __sync_val_compare_and_swap(b, c, 0); }
int d(void) {
while (1) {
char e;
a(&e, e);
}
}
$ LANG=C sh4-unknown-linux-gnu-gcc -o bug.o -c bug.c
<ok>
$ LANG=C sh4-unknown-linux-gnu-gcc -O -o bug.o -c bug.c
bug.c: In function 'd':
bug.c:15:1: error: unable to find a register to spill in class 'R0_REGS'
15 | }
| ^
bug.c:15:1: error: this is the insn:
(insn 18 13 41 4 (parallel [
(set (subreg:SI (reg:QI 6 r6 [174]) 0)
(unspec_volatile:SI [
(mem/v:QI (reg/f:SI 2 r2 [176]) [-1 S1 A8])
(reg:QI 173 [ e ])
(reg:QI 3 r3 [177])
] UNSPECV_CMPXCHG_1))
(set (mem/v:QI (reg/f:SI 2 r2 [176]) [-1 S1 A8])
(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))
]) "bug.c":9:33 401 {atomic_compare_and_swapqi_soft_gusa}
(expr_list:REG_DEAD (reg:QI 173 [ e ])
(expr_list:REG_UNUSED (reg:QI 6 r6 [174])
(expr_list:REG_UNUSED (reg:SI 147 t)
(expr_list:REG_UNUSED (reg:SI 1 r1)
(expr_list:REG_UNUSED (reg:SI 0 r0)
(nil)))))))
bug.c:15: confused by earlier errors, bailing out
$ ./xgcc -B. -v
Reading specs from ./specs
COLLECT_GCC=./xgcc
COLLECT_LTO_WRAPPER=./lto-wrapper
Target: sh4-unknown-linux-gnu
Configured with: ../gcc/configure --target=sh4-unknown-linux-gnu
--prefix=/home/slyfox/dev/git/gcc-sh4/../gcc-sh4-installed
--with-sysroot=/usr/sh4-unknown-linux-gnu --disable-bootstrap
--enable-languages=c --disable-nls CFLAGS=-O0 CXXFLAGS=-O0
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.0.0 20191103 (experimental) (GCC)
