2014-11-17 Zhenqiang Chen <zhenqiang.chen@linaro.org>

	* Makefile.in: Add ccmp.o.
	* ccmp.c: New file.
	* ccmp.h: New file.
	* expr.c: include "ccmp.h"
	(expand_cond_expr_using_cmove): Handle VOIDmode.
	(expand_expr_real_1): Try to expand ccmp.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@217641 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 306 insertions, 0 deletions

diff --git a/gcc/ccmp.c b/gcc/ccmp.c
new file mode 100644
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--- /dev/null
+++ b/gcc/ccmp.c
@@ -0,0 +1,306 @@
+/* Conditional compare related functions
+   Copyright (C) 2014-2014 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "tree.h"
+#include "stringpool.h"
+#include "stor-layout.h"
+#include "regs.h"
+#include "expr.h"
+#include "insn-codes.h"
+#include "optabs.h"
+#include "tree-iterator.h"
+#include "predict.h"
+#include "dominance.h"
+#include "cfg.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "gimple-ssa.h"
+#include "tree-ssanames.h"
+#include "target.h"
+#include "common/common-target.h"
+#include "df.h"
+#include "tree-ssa-live.h"
+#include "tree-outof-ssa.h"
+#include "cfgexpand.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "expmed.h"
+#include "ccmp.h"
+
+/* The following functions expand conditional compare (CCMP) instructions.
+   Here is a short description about the over all algorithm:
+     * ccmp_candidate_p is used to identify the CCMP candidate
+
+     * expand_ccmp_expr is the main entry, which calls expand_ccmp_expr_1
+       to expand CCMP.
+
+     * expand_ccmp_expr_1 uses a recursive algorithm to expand CCMP.
+       It calls two target hooks gen_ccmp_first and gen_ccmp_next to generate
+       CCMP instructions.
+	 - gen_ccmp_first expands the first compare in CCMP.
+	 - gen_ccmp_next expands the following compares.
+
+     * If the final result is not used in a COND_EXPR (checked by function
+       used_in_cond_stmt_p), it calls cstorecc4 pattern to store the CC to a
+       general register.  */
+
+/* Check whether G is a potential conditional compare candidate.  */
+static bool
+ccmp_candidate_p (gimple g)
+{
+  tree rhs = gimple_assign_rhs_to_tree (g);
+  tree lhs, op0, op1;
+  gimple gs0, gs1;
+  enum tree_code tcode, tcode0, tcode1;
+  tcode = TREE_CODE (rhs);
+
+  if (tcode != BIT_AND_EXPR && tcode != BIT_IOR_EXPR)
+    return false;
+
+  lhs = gimple_assign_lhs (g);
+  op0 = TREE_OPERAND (rhs, 0);
+  op1 = TREE_OPERAND (rhs, 1);
+
+  if ((TREE_CODE (op0) != SSA_NAME) || (TREE_CODE (op1) != SSA_NAME)
+      || !has_single_use (lhs))
+    return false;
+
+  gs0 = get_gimple_for_ssa_name (op0);
+  gs1 = get_gimple_for_ssa_name (op1);
+  if (!gs0 || !gs1 || !is_gimple_assign (gs0) || !is_gimple_assign (gs1)
+      /* g, gs0 and gs1 must be in the same basic block, since current stage
+	 is out-of-ssa.  We can not guarantee the correctness when forwording
+	 the gs0 and gs1 into g whithout DATAFLOW analysis.  */
+      || gimple_bb (gs0) != gimple_bb (gs1)
+      || gimple_bb (gs0) != gimple_bb (g))
+    return false;
+
+  if (!(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0)))
+       || POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0))))
+      || !(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))
+	   || POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))))
+    return false;
+
+  tcode0 = gimple_assign_rhs_code (gs0);
+  tcode1 = gimple_assign_rhs_code (gs1);
+  if (TREE_CODE_CLASS (tcode0) == tcc_comparison
+      && TREE_CODE_CLASS (tcode1) == tcc_comparison)
+    return true;
+  if (TREE_CODE_CLASS (tcode0) == tcc_comparison
+      && ccmp_candidate_p (gs1))
+    return true;
+  else if (TREE_CODE_CLASS (tcode1) == tcc_comparison
+	   && ccmp_candidate_p (gs0))
+    return true;
+  /* We skip ccmp_candidate_p (gs1) && ccmp_candidate_p (gs0) since
+     there is no way to set the CC flag.  */
+  return false;
+}
+
+/* Check whether EXP is used in a GIMPLE_COND statement or not.  */
+static bool
+used_in_cond_stmt_p (tree exp)
+{
+  bool expand_cond = false;
+  imm_use_iterator ui;
+  gimple use_stmt;
+  FOR_EACH_IMM_USE_STMT (use_stmt, ui, exp)
+    if (gimple_code (use_stmt) == GIMPLE_COND)
+      {
+	tree op1 = gimple_cond_rhs (use_stmt);
+	if (integer_zerop (op1))
+	  expand_cond = true;
+	BREAK_FROM_IMM_USE_STMT (ui);
+      }
+    else if (gimple_code (use_stmt) == GIMPLE_ASSIGN
+	     && gimple_expr_code (use_stmt) == COND_EXPR)
+      {
+	if (gimple_assign_rhs1 (use_stmt) == exp)
+	  expand_cond = true;
+      }
+
+  return expand_cond;
+}
+
+/* Expand conditional compare gimple G.  A typical CCMP sequence is like:
+
+     CC0 = CMP (a, b);
+     CC1 = CCMP (NE (CC0, 0), CMP (e, f));
+     ...
+     CCn = CCMP (NE (CCn-1, 0), CMP (...));
+
+   hook gen_ccmp_first is used to expand the first compare.
+   hook gen_ccmp_next is used to expand the following CCMP.  */
+static rtx
+expand_ccmp_expr_1 (gimple g)
+{
+  tree exp = gimple_assign_rhs_to_tree (g);
+  enum tree_code code = TREE_CODE (exp);
+  gimple gs0 = get_gimple_for_ssa_name (TREE_OPERAND (exp, 0));
+  gimple gs1 = get_gimple_for_ssa_name (TREE_OPERAND (exp, 1));
+  rtx tmp;
+  enum tree_code code0 = gimple_assign_rhs_code (gs0);
+  enum tree_code code1 = gimple_assign_rhs_code (gs1);
+
+  gcc_assert (code == BIT_AND_EXPR || code == BIT_IOR_EXPR);
+  gcc_assert (gs0 && gs1 && is_gimple_assign (gs0) && is_gimple_assign (gs1));
+
+  if (TREE_CODE_CLASS (code0) == tcc_comparison)
+    {
+      if (TREE_CODE_CLASS (code1) == tcc_comparison)
+	{
+	  int unsignedp0, unsignedp1;
+	  enum rtx_code rcode0, rcode1;
+	  rtx op0, op1, op2, op3, tmp;
+
+	  unsignedp0 = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs0)));
+	  rcode0 = get_rtx_code (code0, unsignedp0);
+	  unsignedp1 = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs1)));
+	  rcode1 = get_rtx_code (code1, unsignedp1);
+
+	  expand_operands (gimple_assign_rhs1 (gs0),
+			   gimple_assign_rhs2 (gs0),
+			   NULL_RTX, &op0, &op1, EXPAND_NORMAL);
+
+	  /* Since the operands of GS1 might clobber CC reg, we expand the
+	     operands of GS1 before GEN_CCMP_FIRST.  */
+	  expand_operands (gimple_assign_rhs1 (gs1),
+			   gimple_assign_rhs2 (gs1),
+			   NULL_RTX, &op2, &op3, EXPAND_NORMAL);
+	  tmp = targetm.gen_ccmp_first (rcode0, op0, op1);
+	  if (!tmp)
+	    return NULL_RTX;
+
+	  return targetm.gen_ccmp_next (tmp, rcode1, op2, op3,
+					get_rtx_code (code, 0));
+	}
+      else
+	{
+  	  rtx op0, op1;
+	  enum rtx_code rcode;
+	  int unsignedp = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs0)));
+
+	  rcode = get_rtx_code (gimple_assign_rhs_code (gs0), unsignedp);
+
+	  /* Hoist the preparation operations above the entire
+	     conditional compare sequence.  */
+	  expand_operands (gimple_assign_rhs1 (gs0),
+			   gimple_assign_rhs2 (gs0),
+			   NULL_RTX, &op0, &op1, EXPAND_NORMAL);
+
+	  gcc_assert (code1 == BIT_AND_EXPR || code1 == BIT_IOR_EXPR);
+
+	  /* Note: We swap the order to make the recursive function work.  */
+	  tmp = expand_ccmp_expr_1 (gs1);
+	  if (tmp)
+	    return targetm.gen_ccmp_next (tmp, rcode, op0, op1,
+					  get_rtx_code (code, 0));
+	}
+    }
+  else
+    {
+      gcc_assert (gimple_assign_rhs_code (gs0) == BIT_AND_EXPR
+                  || gimple_assign_rhs_code (gs0) == BIT_IOR_EXPR);
+
+      if (TREE_CODE_CLASS (gimple_assign_rhs_code (gs1)) == tcc_comparison)
+	{
+  	  rtx op0, op1;
+	  enum rtx_code rcode;
+	  int unsignedp = TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (gs1)));
+
+	  rcode = get_rtx_code (gimple_assign_rhs_code (gs1), unsignedp);
+
+	  /* Hoist the preparation operations above the entire
+	     conditional compare sequence.  */
+	  expand_operands (gimple_assign_rhs1 (gs1),
+			   gimple_assign_rhs2 (gs1),
+			   NULL_RTX, &op0, &op1, EXPAND_NORMAL);
+	  tmp = expand_ccmp_expr_1 (gs0);
+	  if (tmp)
+	    return targetm.gen_ccmp_next (tmp, rcode, op0, op1,
+					  get_rtx_code (code, 0));
+	}
+      else
+	{
+	  gcc_assert (gimple_assign_rhs_code (gs1) == BIT_AND_EXPR
+		      || gimple_assign_rhs_code (gs1) == BIT_IOR_EXPR);
+	}
+    }
+
+  return NULL_RTX;
+}
+
+/* Main entry to expand conditional compare statement G. 
+   Return NULL_RTX if G is not a legal candidate or expand fail.
+   Otherwise return the target.  */
+rtx
+expand_ccmp_expr (gimple g)
+{
+  rtx_insn *last;
+  rtx tmp;
+
+  if (!ccmp_candidate_p (g))
+    return NULL_RTX;
+
+  last = get_last_insn ();
+  tmp = expand_ccmp_expr_1 (g);
+
+  if (tmp)
+    {
+      enum insn_code icode;
+      enum machine_mode cc_mode = CCmode;
+
+      tree lhs = gimple_assign_lhs (g);
+      /* TMP should be CC.  If it is used in a GIMPLE_COND, just return it.
+	 Note: Target needs to define "cbranchcc4".  */
+      if (used_in_cond_stmt_p (lhs))
+	return tmp;
+
+#ifdef SELECT_CC_MODE
+      cc_mode = SELECT_CC_MODE (NE, tmp, const0_rtx);
+#endif
+      /* If TMP is not used in a GIMPLE_COND, store it with a csctorecc4_optab.
+	 Note: Target needs to define "cstorecc4".  */
+      icode = optab_handler (cstore_optab, cc_mode);
+      if (icode != CODE_FOR_nothing)
+	{
+	  tree lhs = gimple_assign_lhs (g);
+	  enum machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
+	  rtx target = gen_reg_rtx (mode);
+	  tmp = emit_cstore (target, icode, NE, cc_mode, cc_mode,
+			     0, tmp, const0_rtx, 1, mode);
+	  if (tmp)
+	    return tmp;
+	}
+    }
+  /* Clean up.  */
+  delete_insns_since (last);
+  return NULL_RTX;
+}
+