if (STRICT_ALIGNMENT)
{
base = plus_constant (XEXP (op0, 0), bitpos / BITS_PER_UNIT);
- base = force_operand (base, NULL);
bitpos %= BITS_PER_UNIT;
- /* Force alignment of the address; load two sequential values. */
- a1 = expand_simple_binop (Pmode, AND, base,
+ /* We load two values to be concatenate. There's an edge condition
+ that bears notice -- an aligned value at the end of a page can
+ only load one value lest we segfault. So the two values we load
+ are at "base & -size" and "(base + size - 1) & -size". If base
+ is unaligned, the addresses will be aligned and sequential; if
+ base is aligned, the addresses will both be equal to base. */
+
+ a1 = expand_simple_binop (Pmode, AND, force_operand (base, NULL),
GEN_INT (-(HOST_WIDE_INT)m_size),
NULL, true, OPTAB_LIB_WIDEN);
mark_reg_pointer (a1, m_bitsize);
set_mem_align (v1, m_bitsize);
v1 = force_reg (mode, validize_mem (v1));
- a2 = plus_constant (a1, GET_MODE_SIZE (mode));
+ a2 = plus_constant (base, GET_MODE_SIZE (mode) - 1);
+ a2 = expand_simple_binop (Pmode, AND, force_operand (a2, NULL),
+ GEN_INT (-(HOST_WIDE_INT)m_size),
+ NULL, true, OPTAB_LIB_WIDEN);
v2 = gen_rtx_MEM (mode, a2);
set_mem_align (v2, m_bitsize);
v2 = force_reg (mode, validize_mem (v2));