diff options
Diffstat (limited to 'gcc/df-problems.c')
| -rw-r--r-- | gcc/df-problems.c | 316 |
1 files changed, 0 insertions, 316 deletions
diff --git a/gcc/df-problems.c b/gcc/df-problems.c index 82a0d0b..e18ffe3 100644 --- a/gcc/df-problems.c +++ b/gcc/df-problems.c @@ -39,7 +39,6 @@ along with GCC; see the file COPYING3. If not see #include "basic-block.h" #include "sbitmap.h" #include "bitmap.h" -#include "target.h" #include "timevar.h" #include "df.h" #include "except.h" @@ -3501,27 +3500,6 @@ df_simulate_find_defs (rtx insn, bitmap defs) } } -/* Find the set of uses for INSN. This includes partial defs. */ - -static void -df_simulate_find_uses (rtx insn, bitmap uses) -{ - df_ref *rec; - unsigned int uid = INSN_UID (insn); - - for (rec = DF_INSN_UID_DEFS (uid); *rec; rec++) - { - df_ref def = *rec; - if (DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)) - bitmap_set_bit (uses, DF_REF_REGNO (def)); - } - for (rec = DF_INSN_UID_USES (uid); *rec; rec++) - { - df_ref use = *rec; - bitmap_set_bit (uses, DF_REF_REGNO (use)); - } -} - /* Find the set of real DEFs, which are not clobbers, for INSN. */ void @@ -3749,301 +3727,7 @@ df_simulate_one_insn_forwards (basic_block bb, rtx insn, bitmap live) } df_simulate_fixup_sets (bb, live); } - -/* Used by the next two functions to encode information about the - memory references we found. */ -#define MEMREF_NORMAL 1 -#define MEMREF_VOLATILE 2 - -/* A subroutine of can_move_insns_across_p called through for_each_rtx. - Return either MEMREF_NORMAL or MEMREF_VOLATILE if a memory is found. */ - -static int -find_memory (rtx *px, void *data ATTRIBUTE_UNUSED) -{ - rtx x = *px; - - if (GET_CODE (x) == ASM_OPERANDS && MEM_VOLATILE_P (x)) - return MEMREF_VOLATILE; - - if (!MEM_P (x)) - return 0; - if (MEM_VOLATILE_P (x)) - return MEMREF_VOLATILE; - if (MEM_READONLY_P (x)) - return 0; - - return MEMREF_NORMAL; -} - -/* A subroutine of can_move_insns_across_p called through note_stores. - DATA points to an integer in which we set either the bit for - MEMREF_NORMAL or the bit for MEMREF_VOLATILE if we find a MEM - of either kind. */ - -static void -find_memory_stores (rtx x, const_rtx pat ATTRIBUTE_UNUSED, - void *data ATTRIBUTE_UNUSED) -{ - int *pflags = (int *)data; - if (GET_CODE (x) == SUBREG) - x = XEXP (x, 0); - /* Treat stores to SP as stores to memory, this will prevent problems - when there are references to the stack frame. */ - if (x == stack_pointer_rtx) - *pflags |= MEMREF_VOLATILE; - if (!MEM_P (x)) - return; - *pflags |= MEM_VOLATILE_P (x) ? MEMREF_VOLATILE : MEMREF_NORMAL; -} - -/* Scan BB backwards, using df_simulate functions to keep track of - lifetimes, up to insn POINT. The result is stored in LIVE. */ - -void -simulate_backwards_to_point (basic_block bb, regset live, rtx point) -{ - rtx insn; - bitmap_copy (live, df_get_live_out (bb)); - df_simulate_initialize_backwards (bb, live); - - /* Scan and update life information until we reach the point we're - interested in. */ - for (insn = BB_END (bb); insn != point; insn = PREV_INSN (insn)) - df_simulate_one_insn_backwards (bb, insn, live); -} - -/* Return true if it is safe to move a group of insns, described by - the range FROM to TO, backwards across another group of insns, - described by ACROSS_FROM to ACROSS_TO. It is assumed that there - are no insns between ACROSS_TO and FROM, but they may be in - different basic blocks; MERGE_BB is the block from which the - insns will be moved. The caller must pass in a regset MERGE_LIVE - which specifies the registers live after TO. - - This function may be called in one of two cases: either we try to - move identical instructions from all successor blocks into their - predecessor, or we try to move from only one successor block. If - OTHER_BRANCH_LIVE is nonnull, it indicates that we're dealing with - the second case. It should contain a set of registers live at the - end of ACROSS_TO which must not be clobbered by moving the insns. - In that case, we're also more careful about moving memory references - and trapping insns. - - We return false if it is not safe to move the entire group, but it - may still be possible to move a subgroup. PMOVE_UPTO, if nonnull, - is set to point at the last moveable insn in such a case. */ -bool -can_move_insns_across (rtx from, rtx to, rtx across_from, rtx across_to, - basic_block merge_bb, regset merge_live, - regset other_branch_live, rtx *pmove_upto) -{ - rtx insn, next, max_to; - bitmap merge_set, merge_use, local_merge_live; - bitmap test_set, test_use; - unsigned i, fail = 0; - bitmap_iterator bi; - int memrefs_in_across = 0; - int mem_sets_in_across = 0; - bool trapping_insns_in_across = false; - - if (pmove_upto != NULL) - *pmove_upto = NULL_RTX; - - /* Find real bounds, ignoring debug insns. */ - while (!NONDEBUG_INSN_P (from) && from != to) - from = NEXT_INSN (from); - while (!NONDEBUG_INSN_P (to) && from != to) - to = PREV_INSN (to); - - for (insn = across_to; ; insn = next) - { - if (NONDEBUG_INSN_P (insn)) - { - memrefs_in_across |= for_each_rtx (&PATTERN (insn), find_memory, - NULL); - note_stores (PATTERN (insn), find_memory_stores, - &mem_sets_in_across); - /* This is used just to find sets of the stack pointer. */ - memrefs_in_across |= mem_sets_in_across; - trapping_insns_in_across |= may_trap_p (PATTERN (insn)); - } - next = PREV_INSN (insn); - if (insn == across_from) - break; - } - - /* Collect: - MERGE_SET = set of registers set in MERGE_BB - MERGE_USE = set of registers used in MERGE_BB and live at its top - MERGE_LIVE = set of registers live at the point inside the MERGE - range that we've reached during scanning - TEST_SET = set of registers set between ACROSS_FROM and ACROSS_END. - TEST_USE = set of registers used between ACROSS_FROM and ACROSS_END, - and live before ACROSS_FROM. */ - - merge_set = BITMAP_ALLOC (®_obstack); - merge_use = BITMAP_ALLOC (®_obstack); - local_merge_live = BITMAP_ALLOC (®_obstack); - test_set = BITMAP_ALLOC (®_obstack); - test_use = BITMAP_ALLOC (®_obstack); - - /* Compute the set of registers set and used in the ACROSS range. */ - if (other_branch_live != NULL) - bitmap_copy (test_use, other_branch_live); - df_simulate_initialize_backwards (merge_bb, test_use); - for (insn = across_to; ; insn = next) - { - if (NONDEBUG_INSN_P (insn)) - { - df_simulate_find_defs (insn, test_set); - df_simulate_defs (insn, test_use); - df_simulate_uses (insn, test_use); - } - next = PREV_INSN (insn); - if (insn == across_from) - break; - } - - /* Compute an upper bound for the amount of insns moved, by finding - the first insn in MERGE that sets a register in TEST_USE, or uses - a register in TEST_SET. We also check for calls, trapping operations, - and memory references. */ - max_to = NULL_RTX; - for (insn = from; ; insn = next) - { - if (CALL_P (insn)) - break; - if (NONDEBUG_INSN_P (insn)) - { - if (may_trap_p (PATTERN (insn)) - && (trapping_insns_in_across || other_branch_live != NULL)) - break; - - /* We cannot move memory stores past each other, or move memory - reads past stores, at least not without tracking them and - calling true_dependence on every pair. - - If there is no other branch and no memory references or - sets in the ACROSS range, we can move memory references - freely, even volatile ones. - - Otherwise, the rules are as follows: volatile memory - references and stores can't be moved at all, and any type - of memory reference can't be moved if there are volatile - accesses or stores in the ACROSS range. That leaves - normal reads, which can be moved, as the trapping case is - dealt with elsewhere. */ - if (other_branch_live != NULL || memrefs_in_across != 0) - { - int mem_ref_flags = 0; - int mem_set_flags = 0; - note_stores (PATTERN (insn), find_memory_stores, &mem_set_flags); - mem_ref_flags = for_each_rtx (&PATTERN (insn), find_memory, - NULL); - /* Catch sets of the stack pointer. */ - mem_ref_flags |= mem_set_flags; - - if ((mem_ref_flags | mem_set_flags) & MEMREF_VOLATILE) - break; - if ((memrefs_in_across & MEMREF_VOLATILE) && mem_ref_flags != 0) - break; - if (mem_set_flags != 0 - || (mem_sets_in_across != 0 && mem_ref_flags != 0)) - break; - } - df_simulate_find_uses (insn, merge_use); - /* We're only interested in uses which use a value live at - the top, not one previously set in this block. */ - bitmap_and_compl_into (merge_use, merge_set); - df_simulate_find_defs (insn, merge_set); - if (bitmap_intersect_p (merge_set, test_use) - || bitmap_intersect_p (merge_use, test_set)) - break; - max_to = insn; - } - next = NEXT_INSN (insn); - if (insn == to) - break; - } - if (max_to != to) - fail = 1; - - if (max_to == NULL_RTX || (fail && pmove_upto == NULL)) - goto out; - - /* Now, lower this upper bound by also taking into account that - a range of insns moved across ACROSS must not leave a register - live at the end that will be clobbered in ACROSS. We need to - find a point where TEST_SET & LIVE == 0. - - Insns in the MERGE range that set registers which are also set - in the ACROSS range may still be moved as long as we also move - later insns which use the results of the set, and make the - register dead again. This is verified by the condition stated - above. We only need to test it for registers that are set in - the moved region. - - MERGE_LIVE is provided by the caller and holds live registers after - TO. */ - bitmap_copy (local_merge_live, merge_live); - for (insn = to; insn != max_to; insn = PREV_INSN (insn)) - df_simulate_one_insn_backwards (merge_bb, insn, local_merge_live); - - /* We're not interested in registers that aren't set in the moved - region at all. */ - bitmap_and_into (local_merge_live, merge_set); - for (;;) - { - if (NONDEBUG_INSN_P (insn)) - { - if (!bitmap_intersect_p (test_set, local_merge_live)) - { - max_to = insn; - break; - } - - df_simulate_one_insn_backwards (merge_bb, insn, - local_merge_live); - } - if (insn == from) - { - fail = 1; - goto out; - } - insn = PREV_INSN (insn); - } - - if (max_to != to) - fail = 1; - - if (pmove_upto) - *pmove_upto = max_to; - - /* For small register class machines, don't lengthen lifetimes of - hard registers before reload. */ - if (! reload_completed - && targetm.small_register_classes_for_mode_p (VOIDmode)) - { - EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi) - { - if (i < FIRST_PSEUDO_REGISTER - && ! fixed_regs[i] - && ! global_regs[i]) - fail = 1; - } - } - - out: - BITMAP_FREE (merge_set); - BITMAP_FREE (merge_use); - BITMAP_FREE (local_merge_live); - BITMAP_FREE (test_set); - BITMAP_FREE (test_use); - - return !fail; -} /*---------------------------------------------------------------------------- |