From acb37d2924de4cd0195f41225e50ae9c46553cca Mon Sep 17 00:00:00 2001
From: Richard Sandiford <rdsandiford@googlemail.com>
Date: Thu, 4 Sep 2008 18:47:35 +0000
Subject: [PATCH] re PR middle-end/37243 (IRA causes wrong code generation)
gcc/
PR middle-end/37243
* ira-build.c (form_loop_tree): Reverse BB walk.
(create_bb_allocnos): Likewise.
* ira-lives.c (make_regno_born_and_dead, regs_set): Delete.
(mark_reg_store): Rename to...
(mark_ref_live): ...this and take a df_ref argument instead of
note_stores arguments. Assert that we have a register.
(mark_reg_clobber): Delete.
(def_conflicts_with_inputs_p): New function.
(mark_reg_conflicts): Delete.
(mark_reg_death): Rename to...
(mark_ref_dead): ...this and take a df_ref argument instead of
a register. Assert that we have a register.
(process_bb_node_lives): Hoist frequency calculation out of
instruction walk. Convert from a forwards scan to a backwards scan.
Use DF_REF_USES and DF_REF_DEFS instead of register notes and
note_stores. Remove EH_RETURN_DATA_REGNO and regs_set handling.
(create_allocno_live_ranges): Don't create regs_set.
From-SVN: r139993
---
gcc/ChangeLog | 21 +++
gcc/ira-build.c | 4 +-
gcc/ira-lives.c | 349 +++++++++++++++++++++---------------------------
3 files changed, 172 insertions(+), 202 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 375a50a2af36..e4e254c106db 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,24 @@
+2008-09-04 Richard Sandiford <rdsandiford@googlemail.com>
+
+ PR middle-end/37243
+ * ira-build.c (form_loop_tree): Reverse BB walk.
+ (create_bb_allocnos): Likewise.
+ * ira-lives.c (make_regno_born_and_dead, regs_set): Delete.
+ (mark_reg_store): Rename to...
+ (mark_ref_live): ...this and take a df_ref argument instead of
+ note_stores arguments. Assert that we have a register.
+ (mark_reg_clobber): Delete.
+ (def_conflicts_with_inputs_p): New function.
+ (mark_reg_conflicts): Delete.
+ (mark_reg_death): Rename to...
+ (mark_ref_dead): ...this and take a df_ref argument instead of
+ a register. Assert that we have a register.
+ (process_bb_node_lives): Hoist frequency calculation out of
+ instruction walk. Convert from a forwards scan to a backwards scan.
+ Use DF_REF_USES and DF_REF_DEFS instead of register notes and
+ note_stores. Remove EH_RETURN_DATA_REGNO and regs_set handling.
+ (create_allocno_live_ranges): Don't create regs_set.
+
2008-09-04 Ian Lance Taylor <iant@google.com>
* rtl.h (LABEL_REF_NONLOCAL_P): Don't check for REG_LABEL_OPERAND
diff --git a/gcc/ira-build.c b/gcc/ira-build.c
index 4f2fb8f53962..6bd49c0cd1b8 100644
--- a/gcc/ira-build.c
+++ b/gcc/ira-build.c
@@ -310,7 +310,7 @@ form_loop_tree (void)
ira_loop_nodes[i].children = NULL;
ira_loop_nodes[i].subloops = NULL;
}
- FOR_EACH_BB_REVERSE (bb)
+ FOR_EACH_BB (bb)
{
bb_node = &ira_bb_nodes[bb->index];
bb_node->bb = bb;
@@ -1343,7 +1343,7 @@ create_bb_allocnos (ira_loop_tree_node_t bb_node)
curr_bb = bb = bb_node->bb;
ira_assert (bb != NULL);
- FOR_BB_INSNS (bb, insn)
+ FOR_BB_INSNS_REVERSE (bb, insn)
if (INSN_P (insn))
create_insn_allocnos (PATTERN (insn), false);
/* It might be a allocno living through from one subloop to
diff --git a/gcc/ira-lives.c b/gcc/ira-lives.c
index 7d6b29fedf10..73cc06235135 100644
--- a/gcc/ira-lives.c
+++ b/gcc/ira-lives.c
@@ -149,15 +149,6 @@ make_regno_dead (int regno)
update_allocno_pressure_excess_length (a);
}
-/* Process the birth and, right after then, death of register
- REGNO. */
-static void
-make_regno_born_and_dead (int regno)
-{
- make_regno_born (regno);
- make_regno_dead (regno);
-}
-
/* The current register pressures for each cover class for the current
basic block. */
static int curr_reg_pressure[N_REG_CLASSES];
@@ -218,40 +209,21 @@ clear_allocno_live (ira_allocno_t a)
sparseset_clear_bit (allocnos_live, ALLOCNO_NUM (a));
}
-/* Record all regs that are set in any one insn. Communication from
- mark_reg_{store,clobber}. */
-static VEC(rtx, heap) *regs_set;
-
-/* Handle the case where REG is set by the insn being scanned, during
- the scan to build live ranges and calculate reg pressure info.
+/* Mark the register referenced by use or def REF as live
Store a 1 in hard_regs_live or allocnos_live for this register or
the corresponding allocno, record how many consecutive hardware
- registers it actually needs.
-
- Note that even if REG does not remain alive after this insn, we
- must mark it here as live, to ensure a conflict between REG and any
- other reg allocnos set in this insn that really do live. This is
- because those other allocnos could be considered after this.
+ registers it actually needs. */
- REG might actually be something other than a register; if so, we do
- nothing.
-
- SETTER is 0 if this register was modified by an auto-increment
- (i.e., a REG_INC note was found for it). */
static void
-mark_reg_store (rtx reg, const_rtx setter ATTRIBUTE_UNUSED,
- void *data ATTRIBUTE_UNUSED)
+mark_ref_live (struct df_ref *ref)
{
+ rtx reg;
int regno;
+ reg = DF_REF_REG (ref);
if (GET_CODE (reg) == SUBREG)
reg = SUBREG_REG (reg);
-
- if (! REG_P (reg))
- return;
-
- VEC_safe_push (rtx, heap, regs_set, reg);
-
+ gcc_assert (REG_P (reg));
regno = REGNO (reg);
if (regno >= FIRST_PSEUDO_REGISTER)
@@ -297,54 +269,35 @@ mark_reg_store (rtx reg, const_rtx setter ATTRIBUTE_UNUSED,
}
}
-/* Like mark_reg_store except notice just CLOBBERs; ignore SETs. */
-static void
-mark_reg_clobber (rtx reg, const_rtx setter, void *data)
+/* Return true if the definition described by DEF conflicts with the
+ instruction's inputs. */
+static bool
+def_conflicts_with_inputs_p (struct df_ref *def)
{
- if (GET_CODE (setter) == CLOBBER)
- mark_reg_store (reg, setter, data);
+ /* Conservatively assume that the condition is true for all clobbers. */
+ return DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER);
}
-/* Record that hard register REG (if it is a hard register) has
- conflicts with all the allocno currently live or the corresponding
- allocno lives at just the current program point. Do not mark REG
- (or the allocno) itself as live. */
+/* Mark the register referenced by definition DEF as dead, if the
+ definition is a total one. Store a 0 in hard_regs_live or
+ allocnos_live for the register. */
static void
-mark_reg_conflicts (rtx reg)
+mark_ref_dead (struct df_ref *def)
{
+ unsigned int i;
+ rtx reg;
int regno;
- if (GET_CODE (reg) == SUBREG)
- reg = SUBREG_REG (reg);
-
- if (! REG_P (reg))
+ if (DF_REF_FLAGS_IS_SET (def, DF_REF_PARTIAL)
+ || DF_REF_FLAGS_IS_SET (def, DF_REF_CONDITIONAL))
return;
+ reg = DF_REF_REG (def);
+ if (GET_CODE (reg) == SUBREG)
+ reg = SUBREG_REG (reg);
+ gcc_assert (REG_P (reg));
regno = REGNO (reg);
- if (regno >= FIRST_PSEUDO_REGISTER)
- make_regno_born_and_dead (regno);
- else if (! TEST_HARD_REG_BIT (ira_no_alloc_regs, regno))
- {
- int last = regno + hard_regno_nregs[regno][GET_MODE (reg)];
-
- while (regno < last)
- {
- make_regno_born_and_dead (regno);
- regno++;
- }
- }
-}
-
-/* Mark REG (or the corresponding allocno) as being dead (following
- the insn being scanned now). Store a 0 in hard_regs_live or
- allocnos_live for the register. */
-static void
-mark_reg_death (rtx reg)
-{
- unsigned int i;
- int regno = REGNO (reg);
-
if (regno >= FIRST_PSEUDO_REGISTER)
{
ira_allocno_t a = ira_curr_regno_allocno_map[regno];
@@ -618,14 +571,14 @@ process_single_reg_class_operands (bool in_p, int freq)
static void
process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
{
- int i;
+ int i, freq;
unsigned int j;
basic_block bb;
rtx insn;
edge e;
edge_iterator ei;
bitmap_iterator bi;
- bitmap reg_live_in;
+ bitmap reg_live_out;
unsigned int px;
bb = loop_tree_node->bb;
@@ -637,9 +590,9 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
high_pressure_start_point[ira_reg_class_cover[i]] = -1;
}
curr_bb_node = loop_tree_node;
- reg_live_in = DF_LR_IN (bb);
+ reg_live_out = DF_LR_OUT (bb);
sparseset_clear (allocnos_live);
- REG_SET_TO_HARD_REG_SET (hard_regs_live, reg_live_in);
+ REG_SET_TO_HARD_REG_SET (hard_regs_live, reg_live_out);
AND_COMPL_HARD_REG_SET (hard_regs_live, eliminable_regset);
AND_COMPL_HARD_REG_SET (hard_regs_live, ira_no_alloc_regs);
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
@@ -659,7 +612,7 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
ira_assert (curr_reg_pressure[cover_class]
<= ira_available_class_regs[cover_class]);
}
- EXECUTE_IF_SET_IN_BITMAP (reg_live_in, FIRST_PSEUDO_REGISTER, j, bi)
+ EXECUTE_IF_SET_IN_BITMAP (reg_live_out, FIRST_PSEUDO_REGISTER, j, bi)
{
ira_allocno_t a = ira_curr_regno_allocno_map[j];
@@ -670,87 +623,91 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
make_regno_born (j);
}
-#ifdef EH_RETURN_DATA_REGNO
- if (bb_has_eh_pred (bb))
- {
- for (j = 0; ; ++j)
- {
- unsigned int regno = EH_RETURN_DATA_REGNO (j);
-
- if (regno == INVALID_REGNUM)
- break;
- make_regno_born_and_dead (regno);
- }
- }
-#endif
-
- /* Allocnos can't go in stack regs at the start of a basic block
- that is reached by an abnormal edge. Likewise for call
- clobbered regs, because caller-save, fixup_abnormal_edges and
- possibly the table driven EH machinery are not quite ready to
- handle such allocnos live across such edges. */
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_ABNORMAL)
- break;
-
- if (e != NULL)
- {
-#ifdef STACK_REGS
- EXECUTE_IF_SET_IN_SPARSESET (allocnos_live, px)
- {
- ALLOCNO_NO_STACK_REG_P (ira_allocnos[px]) = true;
- ALLOCNO_TOTAL_NO_STACK_REG_P (ira_allocnos[px]) = true;
- }
- for (px = FIRST_STACK_REG; px <= LAST_STACK_REG; px++)
- make_regno_born_and_dead (px);
-#endif
- /* No need to record conflicts for call clobbered regs if we
- have nonlocal labels around, as we don't ever try to
- allocate such regs in this case. */
- if (!cfun->has_nonlocal_label)
- for (px = 0; px < FIRST_PSEUDO_REGISTER; px++)
- if (call_used_regs[px])
- make_regno_born_and_dead (px);
- }
-
+ freq = REG_FREQ_FROM_BB (bb);
+ if (freq == 0)
+ freq = 1;
+
/* Scan the code of this basic block, noting which allocnos and
- hard regs are born or die. */
- FOR_BB_INSNS (bb, insn)
+ hard regs are born or die.
+
+ Note that this loop treats uninitialized values as live until
+ the beginning of the block. For example, if an instruction
+ uses (reg:DI foo), and only (subreg:SI (reg:DI foo) 0) is ever
+ set, FOO will remain live until the beginning of the block.
+ Likewise if FOO is not set at all. This is unnecessarily
+ pessimistic, but it probably doesn't matter much in practice. */
+ FOR_BB_INSNS_REVERSE (bb, insn)
{
- rtx link;
- int freq;
+ struct df_ref **def_rec, **use_rec;
+ bool call_p;
if (! INSN_P (insn))
continue;
- freq = REG_FREQ_FROM_BB (BLOCK_FOR_INSN (insn));
- if (freq == 0)
- freq = 1;
-
if (internal_flag_ira_verbose > 2 && ira_dump_file != NULL)
fprintf (ira_dump_file, " Insn %u(l%d): point = %d\n",
INSN_UID (insn), loop_tree_node->parent->loop->num,
curr_point);
- /* Check regs_set is an empty set. */
- gcc_assert (VEC_empty (rtx, regs_set));
-
- /* Mark any allocnos clobbered by INSN as live, so they
- conflict with the inputs. */
- note_stores (PATTERN (insn), mark_reg_clobber, NULL);
+ /* Mark each defined value as live. We need to do this for
+ unused values because they still conflict with quantities
+ that are live at the time of the definition.
+
+ Ignore DF_REF_MAY_CLOBBERs on a call instruction. Such
+ references represent the effect of the called function
+ on a call-clobbered register. Marking the register as
+ live would stop us from allocating it to a call-crossing
+ allocno. */
+ call_p = CALL_P (insn);
+ for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+ if (!call_p || !DF_REF_FLAGS_IS_SET (*def_rec, DF_REF_MAY_CLOBBER))
+ mark_ref_live (*def_rec);
+
+ /* If INSN has multiple outputs, then any value used in one
+ of the outputs conflicts with the other outputs. Model this
+ by making the used value live during the output phase.
+
+ It is unsafe to use !single_set here since it will ignore
+ an unused output. Just because an output is unused does
+ not mean the compiler can assume the side effect will not
+ occur. Consider if ALLOCNO appears in the address of an
+ output and we reload the output. If we allocate ALLOCNO
+ to the same hard register as an unused output we could
+ set the hard register before the output reload insn. */
+ if (GET_CODE (PATTERN (insn)) == PARALLEL && multiple_sets (insn))
+ for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
+ {
+ int i;
+ rtx reg;
+
+ reg = DF_REF_REG (*use_rec);
+ for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
+ {
+ rtx set;
+
+ set = XVECEXP (PATTERN (insn), 0, i);
+ if (GET_CODE (set) == SET
+ && reg_overlap_mentioned_p (reg, SET_DEST (set)))
+ {
+ /* After the previous loop, this is a no-op if
+ REG is contained within SET_DEST (SET). */
+ mark_ref_live (*use_rec);
+ break;
+ }
+ }
+ }
extract_insn (insn);
- process_single_reg_class_operands (true, freq);
-
- /* Mark any allocnos dead after INSN as dead now. */
- for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
- if (REG_NOTE_KIND (link) == REG_DEAD)
- mark_reg_death (XEXP (link, 0));
+ process_single_reg_class_operands (false, freq);
- curr_point++;
+ /* See which defined values die here. */
+ for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+ if (!call_p || !DF_REF_FLAGS_IS_SET (*def_rec, DF_REF_MAY_CLOBBER))
+ mark_ref_dead (*def_rec);
- if (CALL_P (insn))
+ if (call_p)
{
+ /* The current set of live allocnos are live across the call. */
EXECUTE_IF_SET_IN_SPARSESET (allocnos_live, i)
{
ira_allocno_t a = ira_allocnos[i];
@@ -767,67 +724,62 @@ process_bb_node_lives (ira_loop_tree_node_t loop_tree_node)
}
}
- /* Mark any allocnos set in INSN as live. Clobbers are
- processed again, so they will conflict with the reg
- allocnos that are set. */
- note_stores (PATTERN (insn), mark_reg_store, NULL);
-
-#ifdef AUTO_INC_DEC
- for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
- if (REG_NOTE_KIND (link) == REG_INC)
- mark_reg_store (XEXP (link, 0), NULL_RTX, NULL);
-#endif
-
- /* If INSN has multiple outputs, then any allocno that dies
- here and is used inside of an output must conflict with
- the other outputs.
-
- It is unsafe to use !single_set here since it will ignore
- an unused output. Just because an output is unused does
- not mean the compiler can assume the side effect will not
- occur. Consider if ALLOCNO appears in the address of an
- output and we reload the output. If we allocate ALLOCNO
- to the same hard register as an unused output we could
- set the hard register before the output reload insn. */
- if (GET_CODE (PATTERN (insn)) == PARALLEL && multiple_sets (insn))
- for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
- if (REG_NOTE_KIND (link) == REG_DEAD)
- {
- int i;
- int used_in_output = 0;
- rtx reg = XEXP (link, 0);
-
- for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
- {
- rtx set = XVECEXP (PATTERN (insn), 0, i);
-
- if (GET_CODE (set) == SET
- && ! REG_P (SET_DEST (set))
- && ! rtx_equal_p (reg, SET_DEST (set))
- && reg_overlap_mentioned_p (reg, SET_DEST (set)))
- used_in_output = 1;
- }
- if (used_in_output)
- mark_reg_conflicts (reg);
- }
-
- process_single_reg_class_operands (false, freq);
+ curr_point++;
+
+ /* Mark each used value as live. */
+ for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
+ mark_ref_live (*use_rec);
+
+ /* If any defined values conflict with the inputs, mark those
+ defined values as live. */
+ for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+ if (def_conflicts_with_inputs_p (*def_rec))
+ mark_ref_live (*def_rec);
+
+ process_single_reg_class_operands (true, freq);
- /* Mark any allocnos set in INSN and then never used. */
- while (! VEC_empty (rtx, regs_set))
- {
- rtx reg = VEC_pop (rtx, regs_set);
- rtx note = find_regno_note (insn, REG_UNUSED, REGNO (reg));
+ /* See which of the defined values we marked as live are dead
+ before the instruction. */
+ for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+ if (def_conflicts_with_inputs_p (*def_rec))
+ mark_ref_dead (*def_rec);
- if (note)
- mark_reg_death (XEXP (note, 0));
- }
curr_point++;
}
+
+ /* Allocnos can't go in stack regs at the start of a basic block
+ that is reached by an abnormal edge. Likewise for call
+ clobbered regs, because caller-save, fixup_abnormal_edges and
+ possibly the table driven EH machinery are not quite ready to
+ handle such allocnos live across such edges. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ break;
+
+ if (e != NULL)
+ {
+#ifdef STACK_REGS
+ EXECUTE_IF_SET_IN_SPARSESET (allocnos_live, px)
+ {
+ ALLOCNO_NO_STACK_REG_P (ira_allocnos[px]) = true;
+ ALLOCNO_TOTAL_NO_STACK_REG_P (ira_allocnos[px]) = true;
+ }
+ for (px = FIRST_STACK_REG; px <= LAST_STACK_REG; px++)
+ make_regno_born (px);
+#endif
+ /* No need to record conflicts for call clobbered regs if we
+ have nonlocal labels around, as we don't ever try to
+ allocate such regs in this case. */
+ if (!cfun->has_nonlocal_label)
+ for (px = 0; px < FIRST_PSEUDO_REGISTER; px++)
+ if (call_used_regs[px])
+ make_regno_born (px);
+ }
+
EXECUTE_IF_SET_IN_SPARSESET (allocnos_live, i)
- {
- make_regno_dead (ALLOCNO_REGNO (ira_allocnos[i]));
- }
+ {
+ make_regno_dead (ALLOCNO_REGNO (ira_allocnos[i]));
+ }
curr_point++;
@@ -944,9 +896,6 @@ void
ira_create_allocno_live_ranges (void)
{
allocnos_live = sparseset_alloc (ira_allocnos_num);
- /* Make a vector that mark_reg_{store,clobber} will store in. */
- if (!regs_set)
- regs_set = VEC_alloc (rtx, heap, 10);
curr_point = 0;
ira_traverse_loop_tree (true, ira_loop_tree_root, NULL,
process_bb_node_lives);
--
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