+
+/* Subroutine of combine_stack_adjustments, called for each basic block. */
+
+static void
+combine_stack_adjustments_for_block (bb)
+ basic_block bb;
+{
+ HOST_WIDE_INT last_sp_adjust = 0;
+ rtx last_sp_set = NULL_RTX;
+ struct csa_memlist *memlist = NULL;
+ rtx pending_delete;
+ rtx insn, next;
+ struct record_stack_memrefs_data data;
+
+ for (insn = bb->head; ; insn = next)
+ {
+ rtx set;
+
+ pending_delete = NULL_RTX;
+ next = NEXT_INSN (insn);
+
+ if (! INSN_P (insn))
+ goto processed;
+
+ set = single_set_for_csa (insn);
+ if (set)
+ {
+ rtx dest = SET_DEST (set);
+ rtx src = SET_SRC (set);
+
+ /* Find constant additions to the stack pointer. */
+ if (dest == stack_pointer_rtx
+ && GET_CODE (src) == PLUS
+ && XEXP (src, 0) == stack_pointer_rtx
+ && GET_CODE (XEXP (src, 1)) == CONST_INT)
+ {
+ HOST_WIDE_INT this_adjust = INTVAL (XEXP (src, 1));
+
+ /* If we've not seen an adjustment previously, record
+ it now and continue. */
+ if (! last_sp_set)
+ {
+ last_sp_set = insn;
+ last_sp_adjust = this_adjust;
+ goto processed;
+ }
+
+ /* If not all recorded memrefs can be adjusted, or the
+ adjustment is now too large for a constant addition,
+ we cannot merge the two stack adjustments. */
+ if (! try_apply_stack_adjustment (last_sp_set, memlist,
+ last_sp_adjust + this_adjust,
+ this_adjust))
+ {
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = insn;
+ last_sp_adjust = this_adjust;
+ goto processed;
+ }
+
+ /* It worked! */
+ pending_delete = insn;
+ last_sp_adjust += this_adjust;
+
+ /* If, by some accident, the adjustments cancel out,
+ delete both insns and start from scratch. */
+ if (last_sp_adjust == 0)
+ {
+ if (last_sp_set == bb->head)
+ bb->head = NEXT_INSN (last_sp_set);
+ flow_delete_insn (last_sp_set);
+
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ }
+
+ goto processed;
+ }
+
+ /* Find a predecrement of exactly the previous adjustment and
+ turn it into a direct store. Obviously we can't do this if
+ there were any intervening uses of the stack pointer. */
+ if (memlist == NULL
+ && GET_CODE (dest) == MEM
+ && ((GET_CODE (XEXP (dest, 0)) == PRE_DEC
+ && (last_sp_adjust
+ == (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest))))
+ || (GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
+ && GET_CODE (XEXP (XEXP (dest, 0), 1)) == PLUS
+ && XEXP (XEXP (XEXP (dest, 0), 1), 0) == stack_pointer_rtx
+ && (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
+ == CONST_INT)
+ && (INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1))
+ == -last_sp_adjust)))
+ && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx
+ && ! reg_mentioned_p (stack_pointer_rtx, src)
+ && memory_address_p (GET_MODE (dest), stack_pointer_rtx)
+ && validate_change (insn, &SET_DEST (set),
+ change_address (dest, VOIDmode,
+ stack_pointer_rtx), 0))
+ {
+ if (last_sp_set == bb->head)
+ bb->head = NEXT_INSN (last_sp_set);
+ flow_delete_insn (last_sp_set);
+
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ last_sp_adjust = 0;
+ goto processed;
+ }
+ }
+
+ data.insn = insn;
+ data.memlist = memlist;
+ if (GET_CODE (insn) != CALL_INSN && last_sp_set
+ && !for_each_rtx (&PATTERN (insn), record_stack_memrefs, &data))
+ {
+ memlist = data.memlist;
+ goto processed;
+ }
+ memlist = data.memlist;
+
+ /* Otherwise, we were not able to process the instruction.
+ Do not continue collecting data across such a one. */
+ if (last_sp_set
+ && (GET_CODE (insn) == CALL_INSN
+ || reg_mentioned_p (stack_pointer_rtx, PATTERN (insn))))
+ {
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ last_sp_adjust = 0;
+ }
+
+ processed:
+ if (insn == bb->end)
+ break;
+
+ if (pending_delete)
+ flow_delete_insn (pending_delete);
+ }
+
+ if (pending_delete)
+ {
+ bb->end = PREV_INSN (pending_delete);
+ flow_delete_insn (pending_delete);
+ }
+}