https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97534
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Richard Earnshaw <rearn...@gcc.gnu.org>: https://gcc.gnu.org/g:dd2c4e4e97331b1b3d9081191d14f8967d73e31c commit r10-9068-gdd2c4e4e97331b1b3d9081191d14f8967d73e31c Author: Richard Earnshaw <rearn...@arm.com> Date: Tue Nov 24 16:21:17 2020 +0000 arm: correctly handle negating INT_MIN in arm_split_atomic_op [PR97534] arm_split_atomic_op handles subtracting a constant by converting it into addition of the negated constant. But if the type of the operand is int and the constant is -1 we currently end up generating invalid RTL which can lead to an abort later on. The problem is that in a HOST_WIDE_INT, INT_MIN is represented as 0xffffffff80000000 and the negation of this is 0x0000000080000000, but that's not a valid constant for use in SImode operations. The fix is straight-forward which is to use gen_int_mode rather than simply GEN_INT. This knows how to correctly sign-extend the negated constant when this is needed. gcc/ PR target/97534 * config/arm/arm.c (arm_split_atomic_op): Use gen_int_mode when negating a const_int. gcc/testsuite * gcc.dg/pr97534.c: New test.
