#include "output.h"
#include "except.h"
+/* In case alternate_exit_block contains copy from pseudo, to return value,
+ record the pseudo here. In such case the pseudo must be set to function
+ return in the sibcall sequence. */
+static rtx return_value_pseudo;
+
static int identify_call_return_value PARAMS ((rtx, rtx *, rtx *));
static rtx skip_copy_to_return_value PARAMS ((rtx));
static rtx skip_use_of_return_value PARAMS ((rtx, enum rtx_code));
static int sequence_uses_addressof PARAMS ((rtx));
static void purge_reg_equiv_notes PARAMS ((void));
static void purge_mem_unchanging_flag PARAMS ((rtx));
+static rtx skip_unreturned_value PARAMS ((rtx));
/* Examine a CALL_PLACEHOLDER pattern and determine where the call's
return value is located. P_HARD_RETURN receives the hard register
if (! set)
return orig_insn;
+ if (return_value_pseudo)
+ {
+ if (SET_DEST (set) == return_value_pseudo)
+ return insn;
+ return orig_insn;
+ }
+
/* The destination must be the same as the called function's return
value to ensure that any return value is put in the same place by the
current function and the function we're calling.
&& SET_SRC (set) == softret)
return insn;
+ /* Recognize the situation when the called function's return value
+ is copied in two steps: first into an intermediate pseudo, then
+ the into the calling functions return value register. */
+
+ if (REG_P (SET_DEST (set))
+ && SET_SRC (set) == softret)
+ {
+ rtx x = SET_DEST (set);
+
+ insn = next_nonnote_insn (insn);
+ if (! insn)
+ return orig_insn;
+
+ set = single_set (insn);
+ if (! set)
+ return orig_insn;
+
+ if (SET_DEST (set) == current_function_return_rtx
+ && REG_P (SET_DEST (set))
+ && OUTGOING_REGNO (REGNO (SET_DEST (set))) == REGNO (hardret)
+ && SET_SRC (set) == x)
+ return insn;
+ }
+
/* It did not look like a copy of the return value, so return the
same insn we were passed. */
return orig_insn;
return orig_insn;
}
+/* In case function does not return value, we get clobber of pseudo followed
+ by set to hard return value. */
+static rtx
+skip_unreturned_value (orig_insn)
+ rtx orig_insn;
+{
+ rtx insn = next_nonnote_insn (orig_insn);
+
+ /* Skip possible clobber of pseudo return register. */
+ if (insn
+ && GET_CODE (insn) == INSN
+ && GET_CODE (PATTERN (insn)) == CLOBBER
+ && REG_P (XEXP (PATTERN (insn), 0))
+ && (REGNO (XEXP (PATTERN (insn), 0)) >= FIRST_PSEUDO_REGISTER))
+ {
+ rtx set_insn = next_nonnote_insn (insn);
+ rtx set;
+ if (!set_insn)
+ return insn;
+ set = single_set (set_insn);
+ if (!set
+ || SET_SRC (set) != XEXP (PATTERN (insn), 0)
+ || SET_DEST (set) != current_function_return_rtx)
+ return insn;
+ return set_insn;
+ }
+ return orig_insn;
+}
+
/* If the first real insn after ORIG_INSN adjusts the stack pointer
by a constant, return the insn with the stack pointer adjustment.
Otherwise return ORIG_INSN. */
rtx insn;
rtx end;
{
+ rtx new_insn;
/* END might be a note, so get the last nonnote insn of the block. */
end = next_nonnote_insn (PREV_INSN (end));
/* Skip over copying from the call's return value pseudo into
this function's hard return register and if that's the end
of the block, we're OK. */
- insn = skip_copy_to_return_value (insn);
+ new_insn = skip_copy_to_return_value (insn);
+
+ /* In case we return value in pseudo, we must set the pseudo to
+ return value of called function, otherwise we are returning
+ something else. */
+ if (return_value_pseudo && insn == new_insn)
+ return 0;
+ insn = new_insn;
+
if (insn == end)
return 1;
if (insn == end)
return 1;
+ /* Skip over a CLOBBER of the return value as a hard reg. */
+ insn = skip_unreturned_value (insn);
+ if (insn == end)
+ return 1;
+
/* Skip over a USE of the return value (as a hard reg). */
insn = skip_use_of_return_value (insn, USE);
if (insn == end)
if (code == MEM)
return 0;
- /* Scan all subexpressions. */
+ /* Scan all subexpressions. */
fmt = GET_RTX_FORMAT (code);
for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
{
return;
}
- /* Scan all subexpressions. */
+ /* Scan all subexpressions. */
fmt = GET_RTX_FORMAT (code);
for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
{
if (XEXP (PATTERN (insn), 3))
LABEL_PRESERVE_P (XEXP (PATTERN (insn), 3)) = 0;
- /* "Delete" the placeholder insn. */
+ /* "Delete" the placeholder insn. */
PUT_CODE (insn, NOTE);
NOTE_SOURCE_FILE (insn) = 0;
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
ahead and find all the EH labels. */
find_exception_handler_labels ();
- /* Run a jump optimization pass to clean up the CFG. We primarily want
- this to thread jumps so that it is obvious which blocks jump to the
- epilouge. */
- jump_optimize_minimal (insns);
-
+ rebuild_jump_labels (insns);
/* We need cfg information to determine which blocks are succeeded
only by the epilogue. */
find_basic_blocks (insns, max_reg_num (), 0);
- cleanup_cfg ();
+ cleanup_cfg (CLEANUP_PRE_SIBCALL | CLEANUP_PRE_LOOP);
/* If there are no basic blocks, then there is nothing to do. */
if (n_basic_blocks == 0)
return;
+ return_value_pseudo = NULL_RTX;
+
/* Find the exit block.
It is possible that we have blocks which can reach the exit block
insn;
insn = NEXT_INSN (insn))
{
+ rtx set;
/* This should only happen once, at the start of this block. */
if (GET_CODE (insn) == CODE_LABEL)
continue;
&& GET_CODE (PATTERN (insn)) == USE)
continue;
+ /* Exit block also may contain copy from pseudo containing
+ return value to hard register. */
+ if (GET_CODE (insn) == INSN
+ && (set = single_set (insn))
+ && SET_DEST (set) == current_function_return_rtx
+ && REG_P (SET_SRC (set))
+ && !return_value_pseudo)
+ {
+ return_value_pseudo = SET_SRC (set);
+ continue;
+ }
+
break;
}
valid alternate exit block. */
if (insn == NULL)
alternate_exit = e->src;
+ else
+ return_value_pseudo = NULL;
}
/* If the function uses ADDRESSOF, we can't (easily) determine
/* See if there are any reasons we can't perform either sibling or
tail call optimizations. We must be careful with stack slots
- which are live at potential optimization sites. ?!? The first
+ which are live at potential optimization sites. ??? The first
test is overly conservative and should be replaced. */
if (frame_offset
/* Can't take address of local var if used by recursive call. */
|| current_function_uses_addressof
+ /* Any function that calls setjmp might have longjmp called from
+ any called function. ??? We really should represent this
+ properly in the CFG so that this needn't be special cased. */
+ || current_function_calls_setjmp
/* Can't if more than one successor or single successor is not
exit block. These two tests prevent tail call optimization
in the presense of active exception handlers. */
|| (call_block->succ->dest != EXIT_BLOCK_PTR
&& call_block->succ->dest != alternate_exit)
/* If this call doesn't end the block, there are operations at
- the end of the block which we must execute after returning. */
+ the end of the block which we must execute after returning. */
|| ! call_ends_block_p (insn, call_block->end))
sibcall = 0, tailrecursion = 0;
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