https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118248
--- Comment #12 from Stefan Schulze Frielinghaus <stefansf at gcc dot gnu.org> --- Confirmed. Function riscv_block_move_straight() is called to copy 4 bytes. bits equals 64 which means delta equals 8. This in turn renders regs = XALLOCAVEC (rtx, length / delta - 1); into an alloca() call with a negative argument which segfaults. I guess something along the lines is required: diff --git a/gcc/config/riscv/riscv-string.cc b/gcc/config/riscv/riscv-string.cc index 408eb07e87f..8d37cdea114 100644 --- a/gcc/config/riscv/riscv-string.cc +++ b/gcc/config/riscv/riscv-string.cc @@ -814,6 +814,8 @@ riscv_block_move_straight (rtx dest, rtx src, unsigned HOST_WIDE_INT length, mode = mode_for_size (bits, MODE_INT, 0).require (); delta = bits / BITS_PER_UNIT; + if (delta > length) + delta = length; /* Allocate a buffer for the temporary registers. */ regs = XALLOCAVEC (rtx, length / delta - 1);
