https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79912
--- Comment #4 from Kito Cheng <npickito at gmail dot com> ---
Hi Eric:
>> vfscanf.c: In function ‘_IO_vfscanf_internal’:
>> vfscanf.c:3050:1: error: unable to generate reloads for:
>> (insn 11026 11523 5651 1080 (set (reg:QI 3515)
>> (mem/c:QI (plus:SI (reg/f:SI 65 frame)
>> (const_int -1568 [0xfffffffffffff9e0])) [65 %sfp+-1504 S1
>> A32])) "vfscanf.c":266 138 {*movqi_internal}
>> (expr_list:REG_DEAD (reg:QI 3956)
>> (nil)))
> I presume that it's not a valid address? If so, why isn't it valid?
RISC-V have 12-bit signed immediate for offset (2047~-2048), so it's should be
valid address.
Here is another simple case in gcc testsuite:
riscv32-unknown-linux-gnu-gcc gcc/testsuite/gcc.c-torture/compile/pr52750.c -O0
-march=rv32imafd -mabi=ilp32d
/home/kito/riscv-workspace/riscv-gnu-toolchain/riscv-gcc/gcc/testsuite/gcc.c-torture/compile/pr52750.c:
In function ‘foo’:
/home/kito/riscv-workspace/riscv-gnu-toolchain/riscv-gcc/gcc/testsuite/gcc.c-torture/compile/pr52750.c:11:1:
error: unable to generate reloads for:
}
^
(insn 194 197 145 2 (set (reg:QI 180)
(mem/c:QI (plus:SI (reg/f:SI 65 frame)
(const_int -268 [0xfffffffffffffef4])) [2 %sfp+-204 S1 A32]))
"/home/kito/riscv-workspace/riscv-gnu-toolchain/riscv-gcc/gcc/testsuite/gcc.c-torture/compile/pr52750.c":10
138 {*movqi_internal}
(expr_list:REG_DEAD (reg:QI 183)
(nil)))
/home/kito/riscv-workspace/riscv-gnu-toolchain/riscv-gcc/gcc/testsuite/gcc.c-torture/compile/pr52750.c:11:1:
internal compiler error: in curr_insn_transform, at lra-constraints.c:3785
0xa9f298 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
../../../src/gcc/trunk/gcc/rtl-error.c:108
0x9a2001 curr_insn_transform
../../../src/gcc/trunk/gcc/lra-constraints.c:3785
0x9a3286 lra_constraints(bool)
../../../src/gcc/trunk/gcc/lra-constraints.c:4754
0x98cf7c lra(_IO_FILE*)
../../../src/gcc/trunk/gcc/lra.c:2392
0x942ddb do_reload
../../../src/gcc/trunk/gcc/ira.c:5451
0x942ddb execute
../../../src/gcc/trunk/gcc/ira.c:5635
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
