2012-08-01 Richard Henderson <rth@redhat.com>
+ PR middle-end/34548
+ * function.h (struct rtl_data): Add max_dynamic_stack_alignment.
+ * cfgexpand.c (gimple_expand_cfg): Initialise it.
+ * explow.c (allocate_dynamic_stack_space): Set it. Simplify
+ alignment requirements given the known alignment of dynamic_offset.
+ * function.c (instantiate_virtual_regs): Align dtnamic_offset.
+
+2012-08-01 Richard Henderson <rth@redhat.com>
+
* expmed.h (NUM_MODE_PARTIAL_INT): New.
(NUM_MODE_VECTOR_INT, NUM_MODE_IP_INT, NUM_MODE_IPV_INT): New.
(struct expmed_op_cheap): Size one array on NUM_MODE_IPV_INT.
{
HOST_WIDE_INT stack_usage_size = -1;
rtx final_label, final_target, target;
- unsigned extra_align = 0;
bool must_align;
/* If we're asking for zero bytes, it doesn't matter what we point
else if (size_align < BITS_PER_UNIT)
size_align = BITS_PER_UNIT;
- /* We can't attempt to minimize alignment necessary, because we don't
- know the final value of preferred_stack_boundary yet while executing
- this code. */
- if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
- crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
-
/* We will need to ensure that the address we return is aligned to
- REQUIRED_ALIGN. If STACK_DYNAMIC_OFFSET is defined, we don't
- always know its final value at this point in the compilation (it
- might depend on the size of the outgoing parameter lists, for
- example), so we must align the value to be returned in that case.
- (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
- STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
- We must also do an alignment operation on the returned value if
- the stack pointer alignment is less strict than REQUIRED_ALIGN.
-
- If we have to align, we must leave space in SIZE for the hole
- that might result from the alignment operation. */
-
- must_align = (crtl->preferred_stack_boundary < required_align);
- if (must_align)
+ REQUIRED_ALIGN. If that alignment is no larger than
+ PREFERRED_STACK_BOUNDARY, we can handle everything without an
+ explicit alignment. */
+ if (required_align <= PREFERRED_STACK_BOUNDARY)
{
- if (required_align > PREFERRED_STACK_BOUNDARY)
- extra_align = PREFERRED_STACK_BOUNDARY;
- else if (required_align > STACK_BOUNDARY)
- extra_align = STACK_BOUNDARY;
- else
- extra_align = BITS_PER_UNIT;
+ if (crtl->preferred_stack_boundary < required_align)
+ crtl->preferred_stack_boundary = required_align;
+ if (crtl->max_dynamic_stack_alignment < required_align)
+ crtl->max_dynamic_stack_alignment = required_align;
+ must_align = false;
}
+ else
+ {
+ unsigned extra, extra_align;
- /* ??? STACK_POINTER_OFFSET is always defined now. */
-#if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
- must_align = true;
- extra_align = BITS_PER_UNIT;
-#endif
+ crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
+ crtl->max_dynamic_stack_alignment = PREFERRED_STACK_BOUNDARY;
- if (must_align)
- {
- unsigned extra = (required_align - extra_align) / BITS_PER_UNIT;
+ extra_align = PREFERRED_STACK_BOUNDARY;
+ extra = (required_align - extra_align) / BITS_PER_UNIT;
size = plus_constant (Pmode, size, extra);
size = force_operand (size, NULL_RTX);
if (flag_stack_usage_info)
stack_usage_size += extra;
-
if (extra && size_align > extra_align)
size_align = extra_align;
+ must_align = true;
}
/* Round the size to a multiple of the required stack alignment.
- Since the stack if presumed to be rounded before this allocation,
+ Since the stack is presumed to be rounded before this allocation,
this will maintain the required alignment.
If the stack grows downward, we could save an insn by subtracting