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shrink-wrap.h: Update comment.
2014-05-15 Zhenqiang Chen <zhenqiang.chen@linaro.org> * shrink-wrap.h: Update comment. * shrink-wrap.c: Update comment. (next_block_for_reg): Rename to live_edge_for_reg. (live_edge_for_reg): Allow live_edge->dest has two predecessors. (move_insn_for_shrink_wrap): Split live_edge. (prepre_shrink_wrap): One more parameter for move_insn_for_shrink_wrap. From-SVN: r210457
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Zhenqiang Chen
Zhenqiang Chen
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@ -1,3 +1,12 @@
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2014-05-15 Zhenqiang Chen <zhenqiang.chen@linaro.org>
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* shrink-wrap.h: Update comment.
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* shrink-wrap.c: Update comment.
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(next_block_for_reg): Rename to live_edge_for_reg.
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(live_edge_for_reg): Allow live_edge->dest has two predecessors.
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(move_insn_for_shrink_wrap): Split live_edge.
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(prepre_shrink_wrap): One more parameter for move_insn_for_shrink_wrap.
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2014-05-14 Eric Botcazou <ebotcazou@adacore.com>
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* config/sparc/sparc-protos.h (sparc_absnegfloat_split_legitimate):
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@ -1,4 +1,4 @@
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/* Expands front end tree to back end RTL for GCC.
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/* Shrink-wrapping related optimizations.
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Copyright (C) 1987-2014 Free Software Foundation, Inc.
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This file is part of GCC.
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@ -110,12 +110,12 @@ requires_stack_frame_p (rtx insn, HARD_REG_SET prologue_used,
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return false;
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}
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/* See whether BB has a single successor that uses [REGNO, END_REGNO),
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and if BB is its only predecessor. Return that block if so,
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otherwise return null. */
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/* See whether there has a single live edge from BB, which dest uses
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[REGNO, END_REGNO). Return the live edge if its dest bb has
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one or two predecessors. Otherwise return NULL. */
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static basic_block
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next_block_for_reg (basic_block bb, int regno, int end_regno)
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static edge
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live_edge_for_reg (basic_block bb, int regno, int end_regno)
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{
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edge e, live_edge;
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edge_iterator ei;
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@ -148,25 +148,30 @@ next_block_for_reg (basic_block bb, int regno, int end_regno)
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if (live_edge->flags & EDGE_ABNORMAL)
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return NULL;
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if (EDGE_COUNT (live_edge->dest->preds) > 1)
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/* When live_edge->dest->preds == 2, we can create a new block on
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the edge to make it meet the requirement. */
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if (EDGE_COUNT (live_edge->dest->preds) > 2)
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return NULL;
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return live_edge->dest;
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return live_edge;
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}
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/* Try to move INSN from BB to a successor. Return true on success.
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USES and DEFS are the set of registers that are used and defined
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after INSN in BB. */
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after INSN in BB. SPLIT_P indicates whether a live edge from BB
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is splitted or not. */
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static bool
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move_insn_for_shrink_wrap (basic_block bb, rtx insn,
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const HARD_REG_SET uses,
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const HARD_REG_SET defs)
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const HARD_REG_SET defs,
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bool *split_p)
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{
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rtx set, src, dest;
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bitmap live_out, live_in, bb_uses, bb_defs;
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unsigned int i, dregno, end_dregno, sregno, end_sregno;
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basic_block next_block;
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edge live_edge;
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/* Look for a simple register copy. */
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set = single_set (insn);
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@ -191,10 +196,24 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
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return false;
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/* See whether there is a successor block to which we could move INSN. */
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next_block = next_block_for_reg (bb, dregno, end_dregno);
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if (!next_block)
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live_edge = live_edge_for_reg (bb, dregno, end_dregno);
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if (!live_edge)
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return false;
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next_block = live_edge->dest;
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/* Create a new basic block on the edge. */
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if (EDGE_COUNT (next_block->preds) == 2)
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{
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next_block = split_edge (live_edge);
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bitmap_copy (df_get_live_in (next_block), df_get_live_out (bb));
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df_set_bb_dirty (next_block);
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/* We should not split more than once for a function. */
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gcc_assert (!(*split_p));
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*split_p = true;
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}
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/* At this point we are committed to moving INSN, but let's try to
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move it as far as we can. */
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do
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@ -212,7 +231,9 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
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{
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for (i = dregno; i < end_dregno; i++)
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{
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if (REGNO_REG_SET_P (bb_uses, i) || REGNO_REG_SET_P (bb_defs, i)
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if (*split_p
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|| REGNO_REG_SET_P (bb_uses, i)
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|| REGNO_REG_SET_P (bb_defs, i)
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|| REGNO_REG_SET_P (&DF_LIVE_BB_INFO (bb)->gen, i))
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next_block = NULL;
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CLEAR_REGNO_REG_SET (live_out, i);
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@ -223,7 +244,8 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
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Either way, SRC is now live on entry. */
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for (i = sregno; i < end_sregno; i++)
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{
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if (REGNO_REG_SET_P (bb_defs, i)
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if (*split_p
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|| REGNO_REG_SET_P (bb_defs, i)
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|| REGNO_REG_SET_P (&DF_LIVE_BB_INFO (bb)->gen, i))
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next_block = NULL;
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SET_REGNO_REG_SET (live_out, i);
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@ -252,21 +274,31 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
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/* If we don't need to add the move to BB, look for a single
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successor block. */
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if (next_block)
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next_block = next_block_for_reg (next_block, dregno, end_dregno);
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{
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live_edge = live_edge_for_reg (next_block, dregno, end_dregno);
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if (!live_edge || EDGE_COUNT (live_edge->dest->preds) > 1)
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break;
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next_block = live_edge->dest;
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}
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}
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while (next_block);
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/* BB now defines DEST. It only uses the parts of DEST that overlap SRC
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(next loop). */
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for (i = dregno; i < end_dregno; i++)
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/* For the new created basic block, there is no dataflow info at all.
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So skip the following dataflow update and check. */
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if (!(*split_p))
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{
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CLEAR_REGNO_REG_SET (bb_uses, i);
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SET_REGNO_REG_SET (bb_defs, i);
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}
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/* BB now defines DEST. It only uses the parts of DEST that overlap SRC
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(next loop). */
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for (i = dregno; i < end_dregno; i++)
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{
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CLEAR_REGNO_REG_SET (bb_uses, i);
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SET_REGNO_REG_SET (bb_defs, i);
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}
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/* BB now uses SRC. */
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for (i = sregno; i < end_sregno; i++)
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SET_REGNO_REG_SET (bb_uses, i);
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/* BB now uses SRC. */
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for (i = sregno; i < end_sregno; i++)
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SET_REGNO_REG_SET (bb_uses, i);
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}
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emit_insn_after (PATTERN (insn), bb_note (bb));
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delete_insn (insn);
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@ -286,12 +318,14 @@ prepare_shrink_wrap (basic_block entry_block)
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rtx insn, curr, x;
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HARD_REG_SET uses, defs;
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df_ref *ref;
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bool split_p = false;
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CLEAR_HARD_REG_SET (uses);
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CLEAR_HARD_REG_SET (defs);
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FOR_BB_INSNS_REVERSE_SAFE (entry_block, insn, curr)
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if (NONDEBUG_INSN_P (insn)
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&& !move_insn_for_shrink_wrap (entry_block, insn, uses, defs))
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&& !move_insn_for_shrink_wrap (entry_block, insn, uses, defs,
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&split_p))
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{
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/* Add all defined registers to DEFs. */
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for (ref = DF_INSN_DEFS (insn); *ref; ref++)
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@ -1,4 +1,4 @@
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/* Structure for saving state for a nested function.
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/* Shrink-wrapping related functions.
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Copyright (C) 1989-2014 Free Software Foundation, Inc.
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This file is part of GCC.
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