#include "flags.h"
#include "function.h"
#include "expr.h"
-#include "insn-flags.h"
#include "basic-block.h"
+#include "except.h"
#include "toplev.h"
+#include "reload.h"
+
+
+/* Turn STACK_GROWS_DOWNWARD into a boolean. */
+#ifdef STACK_GROWS_DOWNWARD
+#undef STACK_GROWS_DOWNWARD
+#define STACK_GROWS_DOWNWARD 1
+#else
+#define STACK_GROWS_DOWNWARD 0
+#endif
static int perhaps_ends_bb_p PARAMS ((rtx));
static int optimize_reg_copy_1 PARAMS ((rtx, rtx, rtx));
static int try_auto_increment PARAMS ((rtx, rtx, rtx, rtx, HOST_WIDE_INT, int));
static int find_matches PARAMS ((rtx, struct match *));
+static void replace_in_call_usage PARAMS ((rtx *, int, rtx, rtx));
static int fixup_match_1 PARAMS ((rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *))
;
static int reg_is_remote_constant_p PARAMS ((rtx, rtx, rtx));
{
if (inc_insn_set)
validate_change
- (inc_insn,
+ (inc_insn,
&SET_SRC (inc_insn_set),
XEXP (SET_SRC (inc_insn_set), 0), 1);
validate_change (insn, &XEXP (use, 0),
gen_rtx_fmt_e (inc_code, Pmode, reg), 1);
if (apply_change_group ())
{
+ /* If there is a REG_DEAD note on this insn, we must
+ change this not to REG_UNUSED meaning that the register
+ is set, but the value is dead. Failure to do so will
+ result in a sched1 abort -- when it recomputes lifetime
+ information, the number of REG_DEAD notes will have
+ changed. */
+ rtx note = find_reg_note (insn, REG_DEAD, reg);
+ if (note)
+ PUT_MODE (note, REG_UNUSED);
+
REG_NOTES (insn)
= gen_rtx_EXPR_LIST (REG_INC,
reg, REG_NOTES (insn));
tmp = gen_rtx_REG (word_mode, 10000);
tmp = gen_add3_insn (tmp, tmp, GEN_INT (2));
- /* If we get something that isn't a simple set, or a
+ /* If we get something that isn't a simple set, or a
[(set ..) (clobber ..)], this whole function will go wrong. */
if (GET_CODE (tmp) == SET)
return NULL_RTX;
/* It is a tedious task identifying when the flags register is live and
when it is safe to optimize. Since we process the instruction stream
multiple times, locate and record these live zones by marking the
- mode of the instructions --
+ mode of the instructions --
QImode is used on the instruction at which the flags becomes live.
else if (flags != cc0_rtx)
flags = pc_rtx;
#endif
-
+
/* Simple cases first: if no flags, clear all modes. If confusing,
mark the entire function as being in a flags shadow. */
if (flags == NULL_RTX || flags == pc_rtx)
/* A CALL_INSN might be the last insn of a basic block, if it is inside
an EH region or if there are nonlocal gotos. Note that this test is
very conservative. */
- return flag_exceptions || nonlocal_goto_handler_labels;
-
+ if (nonlocal_goto_handler_labels)
+ return 1;
+ /* FALLTHRU */
default:
- /* All others never end a basic block. */
- return 0;
+ return can_throw_internal (insn);
}
}
\f
Search forward to see if SRC dies before either it or DEST is modified,
but don't scan past the end of a basic block. If so, we can replace SRC
- with DEST and let SRC die in INSN.
+ with DEST and let SRC die in INSN.
This will reduce the number of registers live in that range and may enable
DEST to be tied to SRC, thus often saving one register in addition to a
/* Now walk forward making additional replacements. We want to be able
to undo all the changes if a later substitution fails. */
- subreg = gen_rtx_SUBREG (old_mode, src_reg, 0);
+ subreg = gen_lowpart_SUBREG (old_mode, src_reg);
while (p = NEXT_INSN (p), p != insn)
{
if (! INSN_P (p))
int i;
rtx copy_src, copy_dst;
+ /* ??? Hack. Regmove doesn't examine the CFG, and gets mightily
+ confused by non-call exceptions ending blocks. */
+ if (flag_non_call_exceptions)
+ return;
+
/* Find out where a potential flags register is live, and so that we
can supress some optimizations in those zones. */
mark_flags_life_zones (discover_flags_reg ());
{
src_subreg
= gen_rtx_SUBREG (GET_MODE (SUBREG_REG (dst)),
- src, SUBREG_WORD (dst));
+ src, SUBREG_BYTE (dst));
dst = SUBREG_REG (dst);
}
if (GET_CODE (dst) != REG
dst_class = reg_preferred_class (REGNO (dst));
if (! regclass_compatible_p (src_class, dst_class))
continue;
-
+
if (fixup_match_1 (insn, set, src, src_subreg, dst, pass,
op_no, match_no,
regmove_dump_file))
if (! x)
return;
-
+
code = GET_CODE (x);
if (code == REG)
{
if (REGNO (x) != dst_reg)
return;
-
+
validate_change (insn, loc, src, 1);
return;
}
-
+
/* Process each of our operands recursively. */
fmt = GET_RTX_FORMAT (code);
for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
if (GET_CODE (p) == CALL_INSN)
replace_in_call_usage (& CALL_INSN_FUNCTION_USAGE (p),
REGNO (dst), src, p);
-
+
/* ??? We can't scan past the end of a basic block without updating
the register lifetime info (REG_DEAD/basic_block_live_at_start). */
if (perhaps_ends_bb_p (p))
}
}
\f
-/* Track stack adjustments and stack memory references. Attempt to
+/* Track stack adjustments and stack memory references. Attempt to
reduce the number of stack adjustments by back-propogating across
the memory references.
static int try_apply_stack_adjustment
PARAMS ((rtx, struct csa_memlist *, HOST_WIDE_INT, HOST_WIDE_INT));
static void combine_stack_adjustments_for_block PARAMS ((basic_block));
-static int record_stack_memrefs PARAMS ((rtx *, void *));
+static int record_stack_memrefs PARAMS ((rtx *, void *));
/* Main entry point for stack adjustment combination. */
struct csa_memlist *ml;
rtx set;
- /* We know INSN matches single_set_for_csa, because that's what we
- recognized earlier. However, if INSN is not single_set, it is
- doing double duty as a barrier for frame pointer memory accesses,
- which we are not recording. Therefore, an adjust insn that is not
- single_set may not have a positive delta applied. */
-
- if (delta > 0 && ! single_set (insn))
- return 0;
set = single_set_for_csa (insn);
validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust), 1);
rtx new = gen_rtx_MEM (GET_MODE (*ml->mem),
plus_constant (stack_pointer_rtx, c));
- /* Don't reference memory below the stack pointer. */
- if (c < 0)
- {
- cancel_changes (0);
- return 0;
- }
-
MEM_COPY_ATTRIBUTES (new, *ml->mem);
validate_change (ml->insn, ml->mem, new, 1);
}
}
return 1;
case REG:
- /* ??? We want be able to handle non-memory stack pointer references
- later. For now just discard all insns refering to stack pointer
- outside mem expressions. We would probably want to teach
- validate_replace to simplify expressions first. */
- if (x == stack_pointer_rtx)
+ /* ??? We want be able to handle non-memory stack pointer
+ references later. For now just discard all insns refering to
+ stack pointer outside mem expressions. We would probably
+ want to teach validate_replace to simplify expressions first.
+
+ We can't just compare with STACK_POINTER_RTX because the
+ reference to the stack pointer might be in some other mode.
+ In particular, an explict clobber in an asm statement will
+ result in a QImode clober. */
+ if (REGNO (x) == STACK_POINTER_REGNUM)
return 1;
break;
default:
/* Subroutine of combine_stack_adjustments, called for each basic block. */
-static void
+static void
combine_stack_adjustments_for_block (bb)
basic_block bb;
{
/* 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))
+ we cannot merge the two stack adjustments.
+
+ Also we need to be carefull to not move stack pointer
+ such that we create stack accesses outside the allocated
+ area. We can combine an allocation into the first insn,
+ or a deallocation into the second insn. We can not
+ combine an allocation followed by a deallocation.
+
+ The only somewhat frequent ocurrence of the later is when
+ a function allocates a stack frame but does not use it.
+ For this case, we would need to analyze rtl stream to be
+ sure that allocated area is really unused. This means not
+ only checking the memory references, but also all registers
+ or global memory references possibly containing a stack
+ frame address.
+
+ Perhaps the best way to address this problem is to teach
+ gcc not to allocate stack for objects never used. */
+
+ /* Combine an allocation into the first instruction. */
+ if (STACK_GROWS_DOWNWARD ? this_adjust <= 0 : this_adjust >= 0)
{
- free_csa_memlist (memlist);
- memlist = NULL;
- last_sp_set = insn;
- last_sp_adjust = this_adjust;
- goto processed;
+ if (try_apply_stack_adjustment (last_sp_set, memlist,
+ last_sp_adjust + this_adjust,
+ this_adjust))
+ {
+ /* It worked! */
+ pending_delete = 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)
+ /* Otherwise we have a deallocation. Do not combine with
+ a previous allocation. Combine into the second insn. */
+ else if (STACK_GROWS_DOWNWARD
+ ? last_sp_adjust >= 0 : 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;
+ if (try_apply_stack_adjustment (insn, memlist,
+ last_sp_adjust + this_adjust,
+ -last_sp_adjust))
+ {
+ /* It worked! */
+ flow_delete_insn (last_sp_set);
+ last_sp_set = insn;
+ last_sp_adjust += this_adjust;
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ goto processed;
+ }
}
+ /* Combination failed. Restart processing from here. */
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = insn;
+ last_sp_adjust = this_adjust;
goto processed;
}
}
memlist = data.memlist;
- /* Otherwise, we were not able to process the instruction.
+ /* 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
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