/* Forward declarations */
-static int stack_regs_mentioned_p PARAMS ((rtx pat));
-static void straighten_stack PARAMS ((rtx, stack));
-static void pop_stack PARAMS ((stack, int));
-static rtx *get_true_reg PARAMS ((rtx *));
-
-static int check_asm_stack_operands PARAMS ((rtx));
-static int get_asm_operand_n_inputs PARAMS ((rtx));
-static rtx stack_result PARAMS ((tree));
-static void replace_reg PARAMS ((rtx *, int));
-static void remove_regno_note PARAMS ((rtx, enum reg_note,
- unsigned int));
-static int get_hard_regnum PARAMS ((stack, rtx));
-static rtx emit_pop_insn PARAMS ((rtx, stack, rtx,
- enum emit_where));
-static void emit_swap_insn PARAMS ((rtx, stack, rtx));
-static void move_for_stack_reg PARAMS ((rtx, stack, rtx));
-static int swap_rtx_condition_1 PARAMS ((rtx));
-static int swap_rtx_condition PARAMS ((rtx));
-static void compare_for_stack_reg PARAMS ((rtx, stack, rtx));
-static void subst_stack_regs_pat PARAMS ((rtx, stack, rtx));
-static void subst_asm_stack_regs PARAMS ((rtx, stack));
-static void subst_stack_regs PARAMS ((rtx, stack));
-static void change_stack PARAMS ((rtx, stack, stack,
- enum emit_where));
-static int convert_regs_entry PARAMS ((void));
-static void convert_regs_exit PARAMS ((void));
-static int convert_regs_1 PARAMS ((FILE *, basic_block));
-static int convert_regs_2 PARAMS ((FILE *, basic_block));
-static int convert_regs PARAMS ((FILE *));
-static void print_stack PARAMS ((FILE *, stack));
-static rtx next_flags_user PARAMS ((rtx));
-static void record_label_references PARAMS ((rtx, rtx));
-static bool compensate_edge PARAMS ((edge, FILE *));
+static int stack_regs_mentioned_p (rtx pat);
+static void straighten_stack (rtx, stack);
+static void pop_stack (stack, int);
+static rtx *get_true_reg (rtx *);
+
+static int check_asm_stack_operands (rtx);
+static int get_asm_operand_n_inputs (rtx);
+static rtx stack_result (tree);
+static void replace_reg (rtx *, int);
+static void remove_regno_note (rtx, enum reg_note, unsigned int);
+static int get_hard_regnum (stack, rtx);
+static rtx emit_pop_insn (rtx, stack, rtx, enum emit_where);
+static void emit_swap_insn (rtx, stack, rtx);
+static bool move_for_stack_reg (rtx, stack, rtx);
+static int swap_rtx_condition_1 (rtx);
+static int swap_rtx_condition (rtx);
+static void compare_for_stack_reg (rtx, stack, rtx);
+static bool subst_stack_regs_pat (rtx, stack, rtx);
+static void subst_asm_stack_regs (rtx, stack);
+static bool subst_stack_regs (rtx, stack);
+static void change_stack (rtx, stack, stack, enum emit_where);
+static int convert_regs_entry (void);
+static void convert_regs_exit (void);
+static int convert_regs_1 (FILE *, basic_block);
+static int convert_regs_2 (FILE *, basic_block);
+static int convert_regs (FILE *);
+static void print_stack (FILE *, stack);
+static rtx next_flags_user (rtx);
+static void record_label_references (rtx, rtx);
+static bool compensate_edge (edge, FILE *);
\f
/* Return nonzero if any stack register is mentioned somewhere within PAT. */
static int
-stack_regs_mentioned_p (pat)
- rtx pat;
+stack_regs_mentioned_p (rtx pat)
{
const char *fmt;
int i;
/* Return nonzero if INSN mentions stacked registers, else return zero. */
int
-stack_regs_mentioned (insn)
- rtx insn;
+stack_regs_mentioned (rtx insn)
{
unsigned int uid, max;
int test;
static rtx ix86_flags_rtx;
static rtx
-next_flags_user (insn)
- rtx insn;
+next_flags_user (rtx insn)
{
/* Search forward looking for the first use of this value.
Stop at block boundaries. */
- while (insn != current_block->end)
+ while (insn != BB_END (current_block))
{
insn = NEXT_INSN (insn);
after this insn. */
static void
-straighten_stack (insn, regstack)
- rtx insn;
- stack regstack;
+straighten_stack (rtx insn, stack regstack)
{
struct stack_def temp_stack;
int top;
/* Pop a register from the stack. */
static void
-pop_stack (regstack, regno)
- stack regstack;
- int regno;
+pop_stack (stack regstack, int regno)
{
int top = regstack->top;
the edges. */
bool
-reg_to_stack (first, file)
- rtx first;
- FILE *file;
+reg_to_stack (rtx first, FILE *file)
{
basic_block bb;
int i;
return false;
/* Ok, floating point instructions exist. If not optimizing,
- build the CFG and run life analysis.
+ build the CFG and run life analysis.
Also need to rebuild life when superblock scheduling is done
as it don't update liveness yet. */
if (!optimize
FOR_EACH_BB_REVERSE (bb)
{
edge e;
- for (e = bb->pred; e; e=e->pred_next)
+ for (e = bb->pred; e; e = e->pred_next)
if (!(e->flags & EDGE_DFS_BACK)
&& e->src != ENTRY_BLOCK_PTR)
BLOCK_INFO (bb)->predecessors++;
reference. */
static void
-record_label_references (insn, pat)
- rtx insn, pat;
+record_label_references (rtx insn, rtx pat)
{
enum rtx_code code = GET_CODE (pat);
int i;
PAT that stopped the search. */
static rtx *
-get_true_reg (pat)
- rtx *pat;
+get_true_reg (rtx *pat)
{
for (;;)
switch (GET_CODE (*pat))
}
}
\f
+/* Set if we find any malformed asms in a block. */
+static bool any_malformed_asm;
+
/* There are many rules that an asm statement for stack-like regs must
follow. Those rules are explained at the top of this file: the rule
numbers below refer to that explanation. */
static int
-check_asm_stack_operands (insn)
- rtx insn;
+check_asm_stack_operands (rtx insn)
{
int i;
int n_clobbers;
if (GET_CODE (body) == PARALLEL)
{
- clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx));
+ clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
for (i = 0; i < XVECLEN (body, 0); i++)
if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
{
/* Avoid further trouble with this insn. */
PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
+ any_malformed_asm = true;
return 0;
}
placed. */
static int
-get_asm_operand_n_inputs (body)
- rtx body;
+get_asm_operand_n_inputs (rtx body)
{
if (GET_CODE (body) == SET && GET_CODE (SET_SRC (body)) == ASM_OPERANDS)
return ASM_OPERANDS_INPUT_LENGTH (SET_SRC (body));
return the REG. Otherwise, return 0. */
static rtx
-stack_result (decl)
- tree decl;
+stack_result (tree decl)
{
rtx result;
/* If the value is supposed to be returned in memory, then clearly
it is not returned in a stack register. */
- if (aggregate_value_p (DECL_RESULT (decl)))
+ if (aggregate_value_p (DECL_RESULT (decl), decl))
return 0;
result = DECL_RTL_IF_SET (DECL_RESULT (decl));
the desired hard REGNO. */
static void
-replace_reg (reg, regno)
- rtx *reg;
- int regno;
+replace_reg (rtx *reg, int regno)
{
if (regno < FIRST_STACK_REG || regno > LAST_STACK_REG
|| ! STACK_REG_P (*reg))
number REGNO from INSN. Remove only one such note. */
static void
-remove_regno_note (insn, note, regno)
- rtx insn;
- enum reg_note note;
- unsigned int regno;
+remove_regno_note (rtx insn, enum reg_note note, unsigned int regno)
{
rtx *note_link, this;
returned if the register is not found. */
static int
-get_hard_regnum (regstack, reg)
- stack regstack;
- rtx reg;
+get_hard_regnum (stack regstack, rtx reg)
{
int i;
cases the movdf pattern to pop. */
static rtx
-emit_pop_insn (insn, regstack, reg, where)
- rtx insn;
- stack regstack;
- rtx reg;
- enum emit_where where;
+emit_pop_insn (rtx insn, stack regstack, rtx reg, enum emit_where where)
{
rtx pop_insn, pop_rtx;
int hard_regno;
If REG is already at the top of the stack, no insn is emitted. */
static void
-emit_swap_insn (insn, regstack, reg)
- rtx insn;
- stack regstack;
- rtx reg;
+emit_swap_insn (rtx insn, stack regstack, rtx reg)
{
int hard_regno;
rtx swap_rtx;
/* Find the previous insn involving stack regs, but don't pass a
block boundary. */
i1 = NULL;
- if (current_block && insn != current_block->head)
+ if (current_block && insn != BB_HEAD (current_block))
{
rtx tmp = PREV_INSN (insn);
- rtx limit = PREV_INSN (current_block->head);
+ rtx limit = PREV_INSN (BB_HEAD (current_block));
while (tmp != limit)
{
if (GET_CODE (tmp) == CODE_LABEL
if (i1)
emit_insn_after (swap_rtx, i1);
else if (current_block)
- emit_insn_before (swap_rtx, current_block->head);
+ emit_insn_before (swap_rtx, BB_HEAD (current_block));
else
emit_insn_before (swap_rtx, insn);
}
\f
/* Handle a move to or from a stack register in PAT, which is in INSN.
- REGSTACK is the current stack. */
+ REGSTACK is the current stack. Return whether a control flow insn
+ was deleted in the process. */
-static void
-move_for_stack_reg (insn, regstack, pat)
- rtx insn;
- stack regstack;
- rtx pat;
+static bool
+move_for_stack_reg (rtx insn, stack regstack, rtx pat)
{
rtx *psrc = get_true_reg (&SET_SRC (pat));
rtx *pdest = get_true_reg (&SET_DEST (pat));
rtx src, dest;
rtx note;
+ bool control_flow_insn_deleted = false;
src = *psrc; dest = *pdest;
If so, just pop the src. */
if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
+ emit_pop_insn (insn, regstack, src, EMIT_AFTER);
+ else
{
- emit_pop_insn (insn, regstack, src, EMIT_AFTER);
-
- delete_insn (insn);
- return;
+ regstack->reg[i] = REGNO (dest);
+ SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
+ CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
}
- regstack->reg[i] = REGNO (dest);
-
- SET_HARD_REG_BIT (regstack->reg_set, REGNO (dest));
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
-
+ control_flow_insn_deleted |= control_flow_insn_p (insn);
delete_insn (insn);
-
- return;
+ return control_flow_insn_deleted;
}
/* The source reg does not die. */
if (find_regno_note (insn, REG_UNUSED, REGNO (dest)))
emit_pop_insn (insn, regstack, dest, EMIT_AFTER);
+ control_flow_insn_deleted |= control_flow_insn_p (insn);
delete_insn (insn);
- return;
+ return control_flow_insn_deleted;
}
/* The destination ought to be dead. */
regstack->top--;
CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (src));
}
- else if ((GET_MODE (src) == XFmode || GET_MODE (src) == TFmode)
+ else if ((GET_MODE (src) == XFmode)
&& regstack->top < REG_STACK_SIZE - 1)
{
/* A 387 cannot write an XFmode value to a MEM without
rtx push_rtx, push_insn;
rtx top_stack_reg = FP_MODE_REG (FIRST_STACK_REG, GET_MODE (src));
- if (GET_MODE (src) == TFmode)
- push_rtx = gen_movtf (top_stack_reg, top_stack_reg);
- else
- push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
+ push_rtx = gen_movxf (top_stack_reg, top_stack_reg);
push_insn = emit_insn_before (push_rtx, insn);
REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_DEAD, top_stack_reg,
REG_NOTES (insn));
}
else
abort ();
+
+ return control_flow_insn_deleted;
}
\f
/* Swap the condition on a branch, if there is one. Return true if we
such. */
static int
-swap_rtx_condition_1 (pat)
- rtx pat;
+swap_rtx_condition_1 (rtx pat)
{
const char *fmt;
int i, r = 0;
}
static int
-swap_rtx_condition (insn)
- rtx insn;
+swap_rtx_condition (rtx insn)
{
rtx pat = PATTERN (insn);
/* Search forward looking for the first use of this value.
Stop at block boundaries. */
- while (insn != current_block->end)
+ while (insn != BB_END (current_block))
{
insn = NEXT_INSN (insn);
if (INSN_P (insn) && reg_mentioned_p (dest, insn))
set up. */
static void
-compare_for_stack_reg (insn, regstack, pat_src)
- rtx insn;
- stack regstack;
- rtx pat_src;
+compare_for_stack_reg (rtx insn, stack regstack, rtx pat_src)
{
rtx *src1, *src2;
rtx src1_note, src2_note;
}
\f
/* Substitute new registers in PAT, which is part of INSN. REGSTACK
- is the current register layout. */
+ is the current register layout. Return whether a control flow insn
+ was deleted in the process. */
-static void
-subst_stack_regs_pat (insn, regstack, pat)
- rtx insn;
- stack regstack;
- rtx pat;
+static bool
+subst_stack_regs_pat (rtx insn, stack regstack, rtx pat)
{
rtx *dest, *src;
+ bool control_flow_insn_deleted = false;
switch (GET_CODE (pat))
{
&& find_regno_note (insn, REG_DEAD, REGNO (*src)))
{
emit_pop_insn (insn, regstack, *src, EMIT_AFTER);
- return;
+ return control_flow_insn_deleted;
}
/* ??? Uninitialized USE should not happen. */
else if (get_hard_regnum (regstack, *src) == -1)
abort ();
}
remove_note (insn, note);
- replace_reg (dest, LAST_STACK_REG);
+ replace_reg (dest, FIRST_STACK_REG + 1);
}
else
{
FP_MODE_REG (REGNO (*dest), SFmode),
nan);
PATTERN (insn) = pat;
- move_for_stack_reg (insn, regstack, pat);
+ control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
}
if (! note && COMPLEX_MODE_P (GET_MODE (*dest))
&& get_hard_regnum (regstack, FP_MODE_REG (REGNO (*dest), DFmode)) == -1)
FP_MODE_REG (REGNO (*dest) + 1, SFmode),
nan);
PATTERN (insn) = pat;
- move_for_stack_reg (insn, regstack, pat);
+ control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
}
}
}
&& (GET_CODE (*src) == REG || GET_CODE (*src) == MEM
|| GET_CODE (*src) == CONST_DOUBLE)))
{
- move_for_stack_reg (insn, regstack, pat);
+ control_flow_insn_deleted |= move_for_stack_reg (insn, regstack, pat);
break;
}
{
case UNSPEC_SIN:
case UNSPEC_COS:
+ case UNSPEC_FRNDINT:
+ case UNSPEC_F2XM1:
/* These insns only operate on the top of the stack. */
src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
break;
case UNSPEC_FPATAN:
+ case UNSPEC_FYL2X:
+ case UNSPEC_FSCALE:
/* These insns operate on the top two stack slots. */
src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
struct stack_def temp_stack;
int regno, j, k, temp;
- temp_stack = *regstack;
+ temp_stack = *regstack;
/* Place operand 1 at the top of stack. */
regno = get_hard_regnum (&temp_stack, *src1);
default:
break;
}
+
+ return control_flow_insn_deleted;
}
\f
/* Substitute hard regnums for any stack regs in INSN, which has
requirements, since record_asm_stack_regs removes any problem asm. */
static void
-subst_asm_stack_regs (insn, regstack)
- rtx insn;
- stack regstack;
+subst_asm_stack_regs (rtx insn, stack regstack)
{
rtx body = PATTERN (insn);
int alt;
for (i = 0, note = REG_NOTES (insn); note; note = XEXP (note, 1))
i++;
- note_reg = (rtx *) alloca (i * sizeof (rtx));
- note_loc = (rtx **) alloca (i * sizeof (rtx *));
- note_kind = (enum reg_note *) alloca (i * sizeof (enum reg_note));
+ note_reg = alloca (i * sizeof (rtx));
+ note_loc = alloca (i * sizeof (rtx *));
+ note_kind = alloca (i * sizeof (enum reg_note));
n_notes = 0;
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
if (GET_CODE (body) == PARALLEL)
{
- clobber_reg = (rtx *) alloca (XVECLEN (body, 0) * sizeof (rtx));
- clobber_loc = (rtx **) alloca (XVECLEN (body, 0) * sizeof (rtx *));
+ clobber_reg = alloca (XVECLEN (body, 0) * sizeof (rtx));
+ clobber_loc = alloca (XVECLEN (body, 0) * sizeof (rtx *));
for (i = 0; i < XVECLEN (body, 0); i++)
if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
/* Substitute stack hard reg numbers for stack virtual registers in
INSN. Non-stack register numbers are not changed. REGSTACK is the
current stack content. Insns may be emitted as needed to arrange the
- stack for the 387 based on the contents of the insn. */
+ stack for the 387 based on the contents of the insn. Return whether
+ a control flow insn was deleted in the process. */
-static void
-subst_stack_regs (insn, regstack)
- rtx insn;
- stack regstack;
+static bool
+subst_stack_regs (rtx insn, stack regstack)
{
rtx *note_link, note;
+ bool control_flow_insn_deleted = false;
int i;
if (GET_CODE (insn) == CALL_INSN)
Any REG_UNUSED notes will be handled by subst_asm_stack_regs. */
subst_asm_stack_regs (insn, regstack);
- return;
+ return control_flow_insn_deleted;
}
if (GET_CODE (PATTERN (insn)) == PARALLEL)
for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
{
if (stack_regs_mentioned_p (XVECEXP (PATTERN (insn), 0, i)))
- subst_stack_regs_pat (insn, regstack,
- XVECEXP (PATTERN (insn), 0, i));
+ control_flow_insn_deleted
+ |= subst_stack_regs_pat (insn, regstack,
+ XVECEXP (PATTERN (insn), 0, i));
}
else
- subst_stack_regs_pat (insn, regstack, PATTERN (insn));
+ control_flow_insn_deleted
+ |= subst_stack_regs_pat (insn, regstack, PATTERN (insn));
}
/* subst_stack_regs_pat may have deleted a no-op insn. If so, any
REG_UNUSED will already have been dealt with, so just return. */
if (GET_CODE (insn) == NOTE || INSN_DELETED_P (insn))
- return;
+ return control_flow_insn_deleted;
/* If there is a REG_UNUSED note on a stack register on this insn,
the indicated reg must be popped. The REG_UNUSED note is removed,
}
else
note_link = &XEXP (note, 1);
+
+ return control_flow_insn_deleted;
}
\f
/* Change the organization of the stack so that it fits a new basic
is no longer needed once this has executed. */
static void
-change_stack (insn, old, new, where)
- rtx insn;
- stack old;
- stack new;
- enum emit_where where;
+change_stack (rtx insn, stack old, stack new, enum emit_where where)
{
int reg;
int update_end = 0;
if (where == EMIT_AFTER)
{
- if (current_block && current_block->end == insn)
+ if (current_block && BB_END (current_block) == insn)
update_end = 1;
insn = NEXT_INSN (insn);
}
}
if (update_end)
- current_block->end = PREV_INSN (insn);
+ BB_END (current_block) = PREV_INSN (insn);
}
\f
/* Print stack configuration. */
static void
-print_stack (file, s)
- FILE *file;
- stack s;
+print_stack (FILE *file, stack s)
{
if (! file)
return;
commit_edge_insertions needs to be called. */
static int
-convert_regs_entry ()
+convert_regs_entry (void)
{
int inserted = 0;
edge e;
be `empty', or the function return value at top-of-stack. */
static void
-convert_regs_exit ()
+convert_regs_exit (void)
{
int value_reg_low, value_reg_high;
stack output_stack;
target block, or copy stack info into the stack of the successor
of the successor hasn't been processed yet. */
static bool
-compensate_edge (e, file)
- edge e;
- FILE *file;
+compensate_edge (edge e, FILE *file)
{
basic_block block = e->src, target = e->dest;
block_info bi = BLOCK_INFO (block);
/* change_stack kills values in regstack. */
tmpstack = regstack;
- change_stack (block->end, &tmpstack, target_stack, EMIT_AFTER);
+ change_stack (BB_END (block), &tmpstack, target_stack, EMIT_AFTER);
return false;
}
/* change_stack kills values in regstack. */
tmpstack = regstack;
- change_stack (block->end, &tmpstack, target_stack,
- (GET_CODE (block->end) == JUMP_INSN
+ change_stack (BB_END (block), &tmpstack, target_stack,
+ (GET_CODE (BB_END (block)) == JUMP_INSN
? EMIT_BEFORE : EMIT_AFTER));
}
else
start_sequence ();
/* ??? change_stack needs some point to emit insns after. */
- after = emit_note (NULL, NOTE_INSN_DELETED);
+ after = emit_note (NOTE_INSN_DELETED);
tmpstack = regstack;
change_stack (after, &tmpstack, target_stack, EMIT_BEFORE);
/* Convert stack register references in one block. */
static int
-convert_regs_1 (file, block)
- FILE *file;
- basic_block block;
+convert_regs_1 (FILE *file, basic_block block)
{
struct stack_def regstack;
block_info bi = BLOCK_INFO (block);
- int inserted, reg;
+ int deleted, inserted, reg;
rtx insn, next;
edge e, beste = NULL;
+ bool control_flow_insn_deleted = false;
inserted = 0;
+ deleted = 0;
+ any_malformed_asm = false;
/* Find the edge we will copy stack from. It should be the most frequent
one as it will get cheapest after compensation code is generated,
beste = e;
}
- /* Entry block does have stack already initialized. */
+ /* Initialize stack at block entry. */
if (bi->stack_in.top == -2)
- inserted |= compensate_edge (beste, file);
+ {
+ if (beste)
+ inserted |= compensate_edge (beste, file);
+ else
+ {
+ /* No predecessors. Create an arbitrary input stack. */
+ int reg;
+
+ bi->stack_in.top = -1;
+ for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
+ if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
+ bi->stack_in.reg[++bi->stack_in.top] = reg;
+ }
+ }
else
+ /* Entry blocks do have stack already initialized. */
beste = NULL;
current_block = block;
/* Process all insns in this block. Keep track of NEXT so that we
don't process insns emitted while substituting in INSN. */
- next = block->head;
+ next = BB_HEAD (block);
regstack = bi->stack_in;
do
{
/* Ensure we have not missed a block boundary. */
if (next == NULL)
abort ();
- if (insn == block->end)
+ if (insn == BB_END (block))
next = NULL;
/* Don't bother processing unless there is a stack reg
INSN_UID (insn));
print_stack (file, ®stack);
}
- subst_stack_regs (insn, ®stack);
+ control_flow_insn_deleted |= subst_stack_regs (insn, ®stack);
}
}
while (next);
print_stack (file, ®stack);
}
- insn = block->end;
+ insn = BB_END (block);
if (GET_CODE (insn) == JUMP_INSN)
insn = PREV_INSN (insn);
set = gen_rtx_SET (VOIDmode, FP_MODE_REG (reg, SFmode),
nan);
insn = emit_insn_after (set, insn);
- subst_stack_regs (insn, ®stack);
+ control_flow_insn_deleted |= subst_stack_regs (insn, ®stack);
}
}
-
- /* Something failed if the stack lives don't match. */
+
+ /* Amongst the insns possibly deleted during the substitution process above,
+ might have been the only trapping insn in the block. We purge the now
+ possibly dead EH edges here to avoid an ICE from fixup_abnormal_edges,
+ called at the end of convert_regs. The order in which we process the
+ blocks ensures that we never delete an already processed edge.
+
+ Note that, at this point, the CFG may have been damaged by the emission
+ of instructions after an abnormal call, which moves the basic block end
+ (and is the reason why we call fixup_abnormal_edges later). So we must
+ be sure that the trapping insn has been deleted before trying to purge
+ dead edges, otherwise we risk purging valid edges.
+
+ ??? We are normally supposed not to delete trapping insns, so we pretend
+ that the insns deleted above don't actually trap. It would have been
+ better to detect this earlier and avoid creating the EH edge in the first
+ place, still, but we don't have enough information at that time. */
+
+ if (control_flow_insn_deleted)
+ purge_dead_edges (block);
+
+ /* Something failed if the stack lives don't match. If we had malformed
+ asms, we zapped the instruction itself, but that didn't produce the
+ same pattern of register kills as before. */
GO_IF_HARD_REG_EQUAL (regstack.reg_set, bi->out_reg_set, win);
- abort ();
+ if (!any_malformed_asm)
+ abort ();
win:
bi->stack_out = regstack;
/* Convert registers in all blocks reachable from BLOCK. */
static int
-convert_regs_2 (file, block)
- FILE *file;
- basic_block block;
+convert_regs_2 (FILE *file, basic_block block)
{
basic_block *stack, *sp;
int inserted;
- stack = (basic_block *) xmalloc (sizeof (*stack) * n_basic_blocks);
+ /* We process the blocks in a top-down manner, in a way such that one block
+ is only processed after all its predecessors. The number of predecessors
+ of every block has already been computed. */
+
+ stack = xmalloc (sizeof (*stack) * n_basic_blocks);
sp = stack;
*sp++ = block;
edge e;
block = *--sp;
- inserted |= convert_regs_1 (file, block);
- BLOCK_INFO (block)->done = 1;
+
+ /* Processing BLOCK is achieved by convert_regs_1, which may purge
+ some dead EH outgoing edge after the deletion of the trapping
+ insn inside the block. Since the number of predecessors of
+ BLOCK's successors was computed based on the initial edge set,
+ we check the necessity to process some of these successors
+ before such an edge deletion may happen. However, there is
+ a pitfall: if BLOCK is the only predecessor of a successor and
+ the edge between them happens to be deleted, the successor
+ becomes unreachable and should not be processed. The problem
+ is that there is no way to preventively detect this case so we
+ stack the successor in all cases and hand over the task of
+ fixing up the discrepancy to convert_regs_1. */
for (e = block->succ; e ; e = e->succ_next)
if (! (e->flags & EDGE_DFS_BACK))
if (!BLOCK_INFO (e->dest)->predecessors)
*sp++ = e->dest;
}
+
+ inserted |= convert_regs_1 (file, block);
+ BLOCK_INFO (block)->done = 1;
}
while (sp != stack);
to the stack-like registers the 387 uses. */
static int
-convert_regs (file)
- FILE *file;
+convert_regs (FILE *file)
{
int inserted;
basic_block b;
block_info bi = BLOCK_INFO (b);
if (! bi->done)
- {
- int reg;
-
- /* Create an arbitrary input stack. */
- bi->stack_in.top = -1;
- for (reg = LAST_STACK_REG; reg >= FIRST_STACK_REG; --reg)
- if (TEST_HARD_REG_BIT (bi->stack_in.reg_set, reg))
- bi->stack_in.reg[++bi->stack_in.top] = reg;
-
- inserted |= convert_regs_2 (file, b);
- }
+ inserted |= convert_regs_2 (file, b);
}
clear_aux_for_blocks ();
OSDN Git Service
