https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106661
Bug ID: 106661
Summary: possible uninitialized variable usage in
store_bit_field_1
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Compiling the trunk with GCC 7.5.0 for a cross to riscv32-linux-gnu produces
the following warning:
In file included from
/bajas/pinskia/src/toolchain-riscv/scripts/../src/gcc/coretypes.h:475:0,
from
/bajas/pinskia/src/toolchain-riscv/scripts/../src/gcc/expmed.cc:26:
/bajas/pinskia/src/toolchain-riscv/scripts/../src/gcc/poly-int.h: In function
‘bool store_bit_field_1(rtx, poly_uint64, poly_uint64, poly_uint64,
poly_uint64, machine_mode, rtx, bool, bool, bool)’:
/bajas/pinskia/src/toolchain-riscv/scripts/../src/gcc/poly-int.h:1107:38:
warning: ‘regnum’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
POLY_SET_COEFF (C, r, i, NCa (a) * b.coeffs[i]);
^
/bajas/pinskia/src/toolchain-riscv/scripts/../src/gcc/expmed.cc:797:21: note:
‘regnum’ was declared here
HOST_WIDE_INT regnum;
^~~~~~
I looked into the code I think the warning is correct, regnum could be
uninitialized if undefined_p is true but constant_multiple_p returns false.
I have not looked into if the warning happens for the trunk or why x86_64 does
not get the warning.
