317 lines
9.4 KiB
C
317 lines
9.4 KiB
C
/* Conditional compare related functions
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Copyright (C) 2014-2015 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "hash-set.h"
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#include "machmode.h"
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#include "vec.h"
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#include "double-int.h"
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#include "input.h"
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#include "alias.h"
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#include "symtab.h"
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#include "wide-int.h"
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#include "inchash.h"
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#include "tree.h"
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#include "fold-const.h"
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#include "stringpool.h"
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#include "stor-layout.h"
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#include "regs.h"
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#include "expr.h"
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#include "insn-codes.h"
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#include "optabs.h"
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#include "tree-iterator.h"
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#include "predict.h"
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#include "dominance.h"
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#include "cfg.h"
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#include "basic-block.h"
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#include "tree-ssa-alias.h"
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#include "internal-fn.h"
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#include "gimple-expr.h"
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#include "is-a.h"
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#include "gimple.h"
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#include "gimple-ssa.h"
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#include "tree-ssanames.h"
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#include "target.h"
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#include "common/common-target.h"
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#include "df.h"
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#include "tree-ssa-live.h"
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#include "tree-outof-ssa.h"
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#include "cfgexpand.h"
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#include "tree-phinodes.h"
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#include "ssa-iterators.h"
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#include "expmed.h"
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#include "ccmp.h"
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/* The following functions expand conditional compare (CCMP) instructions.
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Here is a short description about the over all algorithm:
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* ccmp_candidate_p is used to identify the CCMP candidate
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* expand_ccmp_expr is the main entry, which calls expand_ccmp_expr_1
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to expand CCMP.
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* expand_ccmp_expr_1 uses a recursive algorithm to expand CCMP.
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It calls two target hooks gen_ccmp_first and gen_ccmp_next to generate
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CCMP instructions.
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- gen_ccmp_first expands the first compare in CCMP.
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- gen_ccmp_next expands the following compares.
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* If the final result is not used in a COND_EXPR (checked by function
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used_in_cond_stmt_p), it calls cstorecc4 pattern to store the CC to a
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general register. */
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/* Check whether G is a potential conditional compare candidate. */
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static bool
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ccmp_candidate_p (gimple g)
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{
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tree rhs = gimple_assign_rhs_to_tree (g);
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tree lhs, op0, op1;
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gimple gs0, gs1;
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enum tree_code tcode, tcode0, tcode1;
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tcode = TREE_CODE (rhs);
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if (tcode != BIT_AND_EXPR && tcode != BIT_IOR_EXPR)
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return false;
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lhs = gimple_assign_lhs (g);
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op0 = TREE_OPERAND (rhs, 0);
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op1 = TREE_OPERAND (rhs, 1);
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if ((TREE_CODE (op0) != SSA_NAME) || (TREE_CODE (op1) != SSA_NAME)
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|| !has_single_use (lhs))
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return false;
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gs0 = get_gimple_for_ssa_name (op0);
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gs1 = get_gimple_for_ssa_name (op1);
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if (!gs0 || !gs1 || !is_gimple_assign (gs0) || !is_gimple_assign (gs1)
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/* g, gs0 and gs1 must be in the same basic block, since current stage
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is out-of-ssa. We can not guarantee the correctness when forwording
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the gs0 and gs1 into g whithout DATAFLOW analysis. */
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|| gimple_bb (gs0) != gimple_bb (gs1)
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|| gimple_bb (gs0) != gimple_bb (g))
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return false;
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if (!(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0)))
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|| POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0))))
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|| !(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))
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|| POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))))
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return false;
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tcode0 = gimple_assign_rhs_code (gs0);
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tcode1 = gimple_assign_rhs_code (gs1);
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if (TREE_CODE_CLASS (tcode0) == tcc_comparison
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&& TREE_CODE_CLASS (tcode1) == tcc_comparison)
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return true;
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if (TREE_CODE_CLASS (tcode0) == tcc_comparison
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&& ccmp_candidate_p (gs1))
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return true;
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else if (TREE_CODE_CLASS (tcode1) == tcc_comparison
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&& ccmp_candidate_p (gs0))
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return true;
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/* We skip ccmp_candidate_p (gs1) && ccmp_candidate_p (gs0) since
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there is no way to set the CC flag. */
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return false;
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}
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/* Check whether EXP is used in a GIMPLE_COND statement or not. */
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static bool
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used_in_cond_stmt_p (tree exp)
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{
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bool expand_cond = false;
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imm_use_iterator ui;
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gimple use_stmt;
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FOR_EACH_IMM_USE_STMT (use_stmt, ui, exp)
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if (gimple_code (use_stmt) == GIMPLE_COND)
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{
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tree op1 = gimple_cond_rhs (use_stmt);
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if (integer_zerop (op1))
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expand_cond = true;
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BREAK_FROM_IMM_USE_STMT (ui);
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}
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else if (gimple_code (use_stmt) == GIMPLE_ASSIGN
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&& gimple_expr_code (use_stmt) == COND_EXPR)
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{
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if (gimple_assign_rhs1 (use_stmt) == exp)
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expand_cond = true;
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}
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return expand_cond;
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}
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/* Expand conditional compare gimple G. A typical CCMP sequence is like:
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CC0 = CMP (a, b);
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CC1 = CCMP (NE (CC0, 0), CMP (e, f));
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...
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CCn = CCMP (NE (CCn-1, 0), CMP (...));
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hook gen_ccmp_first is used to expand the first compare.
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hook gen_ccmp_next is used to expand the following CCMP. */
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static rtx
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expand_ccmp_expr_1 (gimple g)
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{
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tree exp = gimple_assign_rhs_to_tree (g);
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enum tree_code code = TREE_CODE (exp);
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gimple gs0 = get_gimple_for_ssa_name (TREE_OPERAND (exp, 0));
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gimple gs1 = get_gimple_for_ssa_name (TREE_OPERAND (exp, 1));
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rtx tmp;
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enum tree_code code0 = gimple_assign_rhs_code (gs0);
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enum tree_code code1 = gimple_assign_rhs_code (gs1);
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gcc_assert (code == BIT_AND_EXPR || code == BIT_IOR_EXPR);
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gcc_assert (gs0 && gs1 && is_gimple_assign (gs0) && is_gimple_assign (gs1));
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if (TREE_CODE_CLASS (code0) == tcc_comparison)
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{
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if (TREE_CODE_CLASS (code1) == tcc_comparison)
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{
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int unsignedp0, unsignedp1;
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enum rtx_code rcode0, rcode1;
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rtx op0, op1, op2, op3, tmp;
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unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs0)));
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rcode0 = get_rtx_code (code0, unsignedp0);
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unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs1)));
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rcode1 = get_rtx_code (code1, unsignedp1);
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expand_operands (gimple_assign_rhs1 (gs0),
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gimple_assign_rhs2 (gs0),
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NULL_RTX, &op0, &op1, EXPAND_NORMAL);
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/* Since the operands of GS1 might clobber CC reg, we expand the
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operands of GS1 before GEN_CCMP_FIRST. */
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expand_operands (gimple_assign_rhs1 (gs1),
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gimple_assign_rhs2 (gs1),
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NULL_RTX, &op2, &op3, EXPAND_NORMAL);
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tmp = targetm.gen_ccmp_first (rcode0, op0, op1);
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if (!tmp)
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return NULL_RTX;
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return targetm.gen_ccmp_next (tmp, rcode1, op2, op3,
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get_rtx_code (code, 0));
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}
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else
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{
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rtx op0, op1;
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enum rtx_code rcode;
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int unsignedp = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs0)));
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rcode = get_rtx_code (gimple_assign_rhs_code (gs0), unsignedp);
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/* Hoist the preparation operations above the entire
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conditional compare sequence. */
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expand_operands (gimple_assign_rhs1 (gs0),
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gimple_assign_rhs2 (gs0),
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NULL_RTX, &op0, &op1, EXPAND_NORMAL);
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gcc_assert (code1 == BIT_AND_EXPR || code1 == BIT_IOR_EXPR);
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/* Note: We swap the order to make the recursive function work. */
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tmp = expand_ccmp_expr_1 (gs1);
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if (tmp)
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return targetm.gen_ccmp_next (tmp, rcode, op0, op1,
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get_rtx_code (code, 0));
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}
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}
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else
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{
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gcc_assert (gimple_assign_rhs_code (gs0) == BIT_AND_EXPR
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|| gimple_assign_rhs_code (gs0) == BIT_IOR_EXPR);
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if (TREE_CODE_CLASS (gimple_assign_rhs_code (gs1)) == tcc_comparison)
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{
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rtx op0, op1;
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enum rtx_code rcode;
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int unsignedp = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs1)));
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rcode = get_rtx_code (gimple_assign_rhs_code (gs1), unsignedp);
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/* Hoist the preparation operations above the entire
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conditional compare sequence. */
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expand_operands (gimple_assign_rhs1 (gs1),
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gimple_assign_rhs2 (gs1),
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NULL_RTX, &op0, &op1, EXPAND_NORMAL);
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tmp = expand_ccmp_expr_1 (gs0);
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if (tmp)
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return targetm.gen_ccmp_next (tmp, rcode, op0, op1,
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get_rtx_code (code, 0));
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}
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else
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{
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gcc_assert (gimple_assign_rhs_code (gs1) == BIT_AND_EXPR
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|| gimple_assign_rhs_code (gs1) == BIT_IOR_EXPR);
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}
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}
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return NULL_RTX;
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}
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/* Main entry to expand conditional compare statement G.
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Return NULL_RTX if G is not a legal candidate or expand fail.
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Otherwise return the target. */
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rtx
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expand_ccmp_expr (gimple g)
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{
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rtx_insn *last;
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rtx tmp;
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if (!ccmp_candidate_p (g))
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return NULL_RTX;
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last = get_last_insn ();
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tmp = expand_ccmp_expr_1 (g);
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if (tmp)
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{
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enum insn_code icode;
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enum machine_mode cc_mode = CCmode;
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tree lhs = gimple_assign_lhs (g);
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/* TMP should be CC. If it is used in a GIMPLE_COND, just return it.
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Note: Target needs to define "cbranchcc4". */
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if (used_in_cond_stmt_p (lhs))
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return tmp;
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#ifdef SELECT_CC_MODE
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cc_mode = SELECT_CC_MODE (NE, tmp, const0_rtx);
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#endif
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/* If TMP is not used in a GIMPLE_COND, store it with a csctorecc4_optab.
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Note: Target needs to define "cstorecc4". */
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icode = optab_handler (cstore_optab, cc_mode);
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if (icode != CODE_FOR_nothing)
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{
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tree lhs = gimple_assign_lhs (g);
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enum machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
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rtx target = gen_reg_rtx (mode);
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tmp = emit_cstore (target, icode, NE, cc_mode, cc_mode,
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0, tmp, const0_rtx, 1, mode);
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if (tmp)
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return tmp;
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}
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}
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/* Clean up. */
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delete_insns_since (last);
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return NULL_RTX;
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}
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