/* Register to Stack convert for GNU compiler.
Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of GCC.
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 void move_for_stack_reg (rtx, stack, rtx);
+static void swap_to_top(rtx, stack, rtx, 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 void subst_stack_regs_pat (rtx, stack, rtx);
+static bool subst_stack_regs_pat (rtx, stack, rtx);
static void subst_asm_stack_regs (rtx, stack);
-static void subst_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);
/* 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);
case FIX:
case FLOAT_EXTEND:
pat = & XEXP (*pat, 0);
+ break;
+
+ case FLOAT_TRUNCATE:
+ if (!flag_unsafe_math_optimizations)
+ return pat;
+ pat = & XEXP (*pat, 0);
+ break;
}
}
\f
/* 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. */
+/* Emit an insns before INSN to swap virtual register SRC1 with
+ the top of stack and virtual register SRC2 with second stack
+ slot. REGSTACK is the stack state before the swaps, and
+ is updated to reflect the swaps. A swap insn is represented as a
+ PARALLEL of two patterns: each pattern moves one reg to the other.
+
+ If SRC1 and/or SRC2 are already at the right place, no swap insn
+ is emitted. */
static void
+swap_to_top (rtx insn, stack regstack, rtx src1, rtx src2)
+{
+ struct stack_def temp_stack;
+ int regno, j, k, temp;
+
+ temp_stack = *regstack;
+
+ /* Place operand 1 at the top of stack. */
+ regno = get_hard_regnum (&temp_stack, src1);
+ if (regno < 0)
+ abort ();
+ if (regno != FIRST_STACK_REG)
+ {
+ k = temp_stack.top - (regno - FIRST_STACK_REG);
+ j = temp_stack.top;
+
+ temp = temp_stack.reg[k];
+ temp_stack.reg[k] = temp_stack.reg[j];
+ temp_stack.reg[j] = temp;
+ }
+
+ /* Place operand 2 next on the stack. */
+ regno = get_hard_regnum (&temp_stack, src2);
+ if (regno < 0)
+ abort ();
+ if (regno != FIRST_STACK_REG + 1)
+ {
+ k = temp_stack.top - (regno - FIRST_STACK_REG);
+ j = temp_stack.top - 1;
+
+ temp = temp_stack.reg[k];
+ temp_stack.reg[k] = temp_stack.reg[j];
+ temp_stack.reg[j] = temp;
+ }
+
+ change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
+}
+\f
+/* Handle a move to or from a stack register in PAT, which is in INSN.
+ REGSTACK is the current stack. Return whether a control flow insn
+ was deleted in the process. */
+
+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
const char *fmt;
int i, r = 0;
- if (GET_RTX_CLASS (GET_CODE (pat)) == '<')
+ if (COMPARISON_P (pat))
{
PUT_CODE (pat, swap_condition (GET_CODE (pat)));
r = 1;
/* 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))
}
\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
+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 CALL:
{
int count;
- for (count = HARD_REGNO_NREGS (REGNO (*dest), GET_MODE (*dest));
+ for (count = hard_regno_nregs[REGNO (*dest)][GET_MODE (*dest)];
--count >= 0;)
{
regstack->reg[++regstack->top] = REGNO (*dest) + count;
}
/* Keep operand 1 matching with destination. */
- if (GET_RTX_CLASS (GET_CODE (pat_src)) == 'c'
+ if (COMMUTATIVE_ARITH_P (pat_src)
&& REG_P (*src1) && REG_P (*src2)
&& REGNO (*src1) != REGNO (*dest))
{
emit_swap_insn (insn, regstack, *src1);
+ /* Input should never die, it is
+ replaced with output. */
src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
+ if (src1_note)
+ abort();
if (STACK_REG_P (*dest))
replace_reg (dest, FIRST_STACK_REG);
- if (src1_note)
- {
- replace_reg (&XEXP (src1_note, 0), FIRST_STACK_REG);
- regstack->top--;
- CLEAR_HARD_REG_BIT (regstack->reg_set, REGNO (*src1));
- }
-
replace_reg (src1, FIRST_STACK_REG);
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));
src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
- {
- struct stack_def temp_stack;
- int regno, j, k, temp;
-
- temp_stack = *regstack;
-
- /* Place operand 1 at the top of stack. */
- regno = get_hard_regnum (&temp_stack, *src1);
- if (regno < 0)
- abort ();
- if (regno != FIRST_STACK_REG)
- {
- k = temp_stack.top - (regno - FIRST_STACK_REG);
- j = temp_stack.top;
-
- temp = temp_stack.reg[k];
- temp_stack.reg[k] = temp_stack.reg[j];
- temp_stack.reg[j] = temp;
- }
-
- /* Place operand 2 next on the stack. */
- regno = get_hard_regnum (&temp_stack, *src2);
- if (regno < 0)
- abort ();
- if (regno != FIRST_STACK_REG + 1)
- {
- k = temp_stack.top - (regno - FIRST_STACK_REG);
- j = temp_stack.top - 1;
-
- temp = temp_stack.reg[k];
- temp_stack.reg[k] = temp_stack.reg[j];
- temp_stack.reg[j] = temp;
- }
-
- change_stack (insn, regstack, &temp_stack, EMIT_BEFORE);
- }
+ swap_to_top (insn, regstack, *src1, *src2);
replace_reg (src1, FIRST_STACK_REG);
replace_reg (src2, FIRST_STACK_REG + 1);
replace_reg (dest, FIRST_STACK_REG);
break;
+ case UNSPEC_FSCALE_FRACT:
+ /* These insns operate on the top two stack slots.
+ first part of double input, double output insn. */
+
+ src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
+ src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
+
+ src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
+ src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
+
+ /* Inputs should never die, they are
+ replaced with outputs. */
+ if ((src1_note) || (src2_note))
+ abort();
+
+ swap_to_top (insn, regstack, *src1, *src2);
+
+ /* Push the result back onto stack. Empty stack slot
+ will be filled in second part of insn. */
+ if (STACK_REG_P (*dest)) {
+ regstack->reg[regstack->top] = REGNO (*dest);
+ SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
+ replace_reg (dest, FIRST_STACK_REG);
+ }
+
+ replace_reg (src1, FIRST_STACK_REG);
+ replace_reg (src2, FIRST_STACK_REG + 1);
+ break;
+
+ case UNSPEC_FSCALE_EXP:
+ /* These insns operate on the top two stack slots./
+ second part of double input, double output insn. */
+
+ src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
+ src2 = get_true_reg (&XVECEXP (pat_src, 0, 1));
+
+ src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
+ src2_note = find_regno_note (insn, REG_DEAD, REGNO (*src2));
+
+ /* Inputs should never die, they are
+ replaced with outputs. */
+ if ((src1_note) || (src2_note))
+ abort();
+
+ swap_to_top (insn, regstack, *src1, *src2);
+
+ /* Push the result back onto stack. Fill empty slot from
+ first part of insn and fix top of stack pointer. */
+ if (STACK_REG_P (*dest)) {
+ regstack->reg[regstack->top - 1] = REGNO (*dest);
+ SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
+ replace_reg (dest, FIRST_STACK_REG + 1);
+ }
+
+ replace_reg (src1, FIRST_STACK_REG);
+ replace_reg (src2, FIRST_STACK_REG + 1);
+ break;
+
+ case UNSPEC_SINCOS_COS:
+ case UNSPEC_TAN_ONE:
+ case UNSPEC_XTRACT_FRACT:
+ /* These insns operate on the top two stack slots,
+ first part of one input, double output insn. */
+
+ src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
+
+ emit_swap_insn (insn, regstack, *src1);
+
+ /* Input should never die, it is
+ replaced with output. */
+ src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
+ if (src1_note)
+ abort();
+
+ /* Push the result back onto stack. Empty stack slot
+ will be filled in second part of insn. */
+ if (STACK_REG_P (*dest)) {
+ regstack->reg[regstack->top + 1] = REGNO (*dest);
+ SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
+ replace_reg (dest, FIRST_STACK_REG);
+ }
+
+ replace_reg (src1, FIRST_STACK_REG);
+ break;
+
+ case UNSPEC_SINCOS_SIN:
+ case UNSPEC_TAN_TAN:
+ case UNSPEC_XTRACT_EXP:
+ /* These insns operate on the top two stack slots,
+ second part of one input, double output insn. */
+
+ src1 = get_true_reg (&XVECEXP (pat_src, 0, 0));
+
+ emit_swap_insn (insn, regstack, *src1);
+
+ /* Input should never die, it is
+ replaced with output. */
+ src1_note = find_regno_note (insn, REG_DEAD, REGNO (*src1));
+ if (src1_note)
+ abort();
+
+ /* Push the result back onto stack. Fill empty slot from
+ first part of insn and fix top of stack pointer. */
+ if (STACK_REG_P (*dest)) {
+ regstack->reg[regstack->top] = REGNO (*dest);
+ SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
+ replace_reg (dest, FIRST_STACK_REG + 1);
+
+ regstack->top++;
+ }
+
+ replace_reg (src1, FIRST_STACK_REG);
+ break;
+
case UNSPEC_SAHF:
/* (unspec [(unspec [(compare)] UNSPEC_FNSTSW)] UNSPEC_SAHF)
The combination matches the PPRO fcomi instruction. */
if (GET_CODE (pat_src) != UNSPEC
|| XINT (pat_src, 1) != UNSPEC_FNSTSW)
abort ();
- /* FALLTHRU */
+ /* Fall through. */
case UNSPEC_FNSTSW:
/* Combined fcomp+fnstsw generated for doing well with
default:
break;
}
+
+ return control_flow_insn_deleted;
}
\f
/* Substitute hard regnums for any stack regs in INSN, which has
/* 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
+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));
+ {
+ if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == CLOBBER)
+ XVECEXP (PATTERN (insn), 0, i)
+ = shallow_copy_rtx (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
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. */
{
value_reg_low = REGNO (retvalue);
value_reg_high = value_reg_low
- + HARD_REGNO_NREGS (value_reg_low, GET_MODE (retvalue)) - 1;
+ + hard_regno_nregs[value_reg_low][GET_MODE (retvalue)] - 1;
}
output_stack = &BLOCK_INFO (EXIT_BLOCK_PTR)->stack_in;
/* 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
{
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
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);
}
}
+
+ /* 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
basic_block *stack, *sp;
int inserted;
+ /* 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;
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);
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 ();
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