gcc/

2011-12-21  Enkovich Ilya  <ilya.enkovich@intel.com>

        PR target/50038
        * implicit-zee.c: Delete.
        * ree.c: New file.
        * Makefile.in: Replace implicit-zee.c with ree.c.
        * config/i386/i386.c (ix86_option_override_internal): Rename
        flag_zee to flag_ree.
        * common.opt (fzee): Ignored.
        (free): New.
        * passes.c (init_optimization_passes): Replace pass_implicit_zee
        with pass_ree.
        * tree-pass.h (pass_implicit_zee): Delete.
        (pass_ree): New.
        * timevar.def (TV_ZEE): Delete.
        (TV_REE): New.
        * doc/invoke.texi: Add -free description.

gcc/testsuite/

2011-12-21  Enkovich Ilya  <ilya.enkovich@intel.com>

        PR target/50038



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@182574 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 0 insertions, 993 deletions

diff --git a/gcc/implicit-zee.c b/gcc/implicit-zee.c
deleted file mode 100644
index 0795c29ff7b..00000000000
--- a/gcc/implicit-zee.c
+++ /dev/null
@@ -1,993 +0,0 @@
-/* Redundant Zero-extension elimination for targets that implicitly
-   zero-extend writes to the lower 32-bit portion of 64-bit registers.
-   Copyright (C) 2010 Free Software Foundation, Inc.
-   Contributed by Sriraman Tallam (tmsriram@google.com) and
-                  Silvius Rus     (rus@google.com)
-
-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/>.  */
-
-
-/* Problem Description :
-   --------------------
-   This pass is intended to be applicable only to targets that implicitly
-   zero-extend 64-bit registers after writing to their lower 32-bit half.
-   For instance, x86_64 zero-extends the upper bits of a register
-   implicitly whenever an instruction writes to its lower 32-bit half.
-   For example, the instruction *add edi,eax* also zero-extends the upper
-   32-bits of rax after doing the addition.  These zero extensions come
-   for free and GCC does not always exploit this well.  That is, it has
-   been observed that there are plenty of cases where GCC explicitly
-   zero-extends registers for x86_64 that are actually useless because
-   these registers were already implicitly zero-extended in a prior
-   instruction.  This pass tries to eliminate such useless zero extension
-   instructions.
-
-   How does this pass work  ?
-   --------------------------
-
-   This pass is run after register allocation.  Hence, all registers that
-   this pass deals with are hard registers.  This pass first looks for a
-   zero-extension instruction that could possibly be redundant. Such zero
-   extension instructions show up in RTL with the pattern :
-   (set (reg:DI x) (zero_extend:DI (reg:SI x))).
-   where x can be any one of the 64-bit hard registers.
-   Now, this pass tries to eliminate this instruction by merging the
-   zero-extension with the definitions of register x. For instance, if
-   one of the definitions of register x was  :
-   (set (reg:SI x) (plus:SI (reg:SI z1) (reg:SI z2))),
-   then the combination converts this into :
-   (set (reg:DI x) (zero_extend:DI (plus:SI (reg:SI z1) (reg:SI z2)))).
-   If all the merged definitions are recognizable assembly instructions,
-   the zero-extension is effectively eliminated.  For example, in x86_64,
-   implicit zero-extensions are captured with appropriate patterns in the
-   i386.md file.  Hence, these merged definition can be matched to a single
-   assembly instruction.  The original zero-extension instruction is then
-   deleted if all the definitions can be merged.
-
-   However, there are cases where the definition instruction cannot be
-   merged with a zero-extend.  Examples are CALL instructions.  In such
-   cases, the original zero extension is not redundant and this pass does
-   not delete it.
-
-   Handling conditional moves :
-   ----------------------------
-
-   Architectures like x86_64 support conditional moves whose semantics for
-   zero-extension differ from the other instructions.  For instance, the
-   instruction *cmov ebx, eax*
-   zero-extends eax onto rax only when the move from ebx to eax happens.
-   Otherwise, eax may not be zero-extended.  Conditional moves appear as
-   RTL instructions of the form
-   (set (reg:SI x) (if_then_else (cond) (reg:SI y) (reg:SI z))).
-   This pass tries to merge a zero-extension with a conditional move by
-   actually merging the defintions of y and z with a zero-extend and then
-   converting the conditional move into :
-   (set (reg:DI x) (if_then_else (cond) (reg:DI y) (reg:DI z))).
-   Since registers y and z are zero-extended, register x will also be
-   zero-extended after the conditional move.  Note that this step has to
-   be done transitively since the definition of a conditional copy can be
-   another conditional copy.
-
-   Motivating Example I :
-   ---------------------
-   For this program :
-   **********************************************
-   bad_code.c
-
-   int mask[1000];
-
-   int foo(unsigned x)
-   {
-     if (x < 10)
-       x = x * 45;
-     else
-       x = x * 78;
-     return mask[x];
-   }
-   **********************************************
-
-   $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination)
-     ........
-     400315:       b8 4e 00 00 00          mov    $0x4e,%eax
-     40031a:       0f af f8                imul   %eax,%edi
-     40031d:       89 ff                   mov    %edi,%edi  --> Useless extend
-     40031f:       8b 04 bd 60 19 40 00    mov    0x401960(,%rdi,4),%eax
-     400326:       c3                      retq
-     ......
-     400330:       ba 2d 00 00 00          mov    $0x2d,%edx
-     400335:       0f af fa                imul   %edx,%edi
-     400338:       89 ff                   mov    %edi,%edi  --> Useless extend
-     40033a:       8b 04 bd 60 19 40 00    mov    0x401960(,%rdi,4),%eax
-     400341:       c3                      retq
-
-   $ gcc -O2 -fzee bad_code.c
-     ......
-     400315:       6b ff 4e                imul   $0x4e,%edi,%edi
-     400318:       8b 04 bd 40 19 40 00    mov    0x401940(,%rdi,4),%eax
-     40031f:       c3                      retq
-     400320:       6b ff 2d                imul   $0x2d,%edi,%edi
-     400323:       8b 04 bd 40 19 40 00    mov    0x401940(,%rdi,4),%eax
-     40032a:       c3                      retq
-
-   Motivating Example II :
-   ---------------------
-
-   Here is an example with a conditional move.
-
-   For this program :
-   **********************************************
-
-   unsigned long long foo(unsigned x , unsigned y)
-   {
-     unsigned z;
-     if (x > 100)
-       z = x + y;
-     else
-       z = x - y;
-     return (unsigned long long)(z);
-   }
-
-   $ gcc -O2 -fsee bad_code.c (Turned on existing sign-extension elimination)
-     ............
-     400360:       8d 14 3e                lea    (%rsi,%rdi,1),%edx
-     400363:       89 f8                   mov    %edi,%eax
-     400365:       29 f0                   sub    %esi,%eax
-     400367:       83 ff 65                cmp    $0x65,%edi
-     40036a:       0f 43 c2                cmovae %edx,%eax
-     40036d:       89 c0                   mov    %eax,%eax  --> Useless extend
-     40036f:       c3                      retq
-
-   $ gcc -O2 -fzee bad_code.c
-     .............
-     400360:       89 fa                   mov    %edi,%edx
-     400362:       8d 04 3e                lea    (%rsi,%rdi,1),%eax
-     400365:       29 f2                   sub    %esi,%edx
-     400367:       83 ff 65                cmp    $0x65,%edi
-     40036a:       89 d6                   mov    %edx,%esi
-     40036c:       48 0f 42 c6             cmovb  %rsi,%rax
-     400370:       c3                      retq
-
-
-   Usefulness :
-   ----------
-
-   This pass reduces the dynamic instruction count of a compression benchmark
-   by 2.8% and improves its run time by about 1%.  The compression benchmark
-   had the following code sequence in a very hot region of code before ZEE
-   optimized it :
-
-   shr $0x5, %edx
-   mov %edx, %edx --> Useless zero-extend  */
-
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "tm.h"
-#include "rtl.h"
-#include "tree.h"
-#include "tm_p.h"
-#include "flags.h"
-#include "regs.h"
-#include "hard-reg-set.h"
-#include "basic-block.h"
-#include "insn-config.h"
-#include "function.h"
-#include "expr.h"
-#include "insn-attr.h"
-#include "recog.h"
-#include "diagnostic-core.h"
-#include "target.h"
-#include "timevar.h"
-#include "optabs.h"
-#include "insn-codes.h"
-#include "rtlhooks-def.h"
-/* Include output.h for dump_file.  */
-#include "output.h"
-#include "params.h"
-#include "timevar.h"
-#include "tree-pass.h"
-#include "df.h"
-#include "cgraph.h"
-
-/* This says if a register is newly created for the purpose of
-   zero-extension.  */
-
-enum insn_merge_code
-{
-  MERGE_NOT_ATTEMPTED = 0,
-  MERGE_SUCCESS
-};
-
-/* This says if a INSN UID or its definition has already been merged
-   with a zero-extend or not.  */
-
-static enum insn_merge_code *is_insn_merge_attempted;
-static int max_insn_uid;
-
-/* Returns the merge code status for INSN.  */
-
-static enum insn_merge_code
-get_insn_status (rtx insn)
-{
-  gcc_assert (INSN_UID (insn) < max_insn_uid);
-  return is_insn_merge_attempted[INSN_UID (insn)];
-}
-
-/* Sets the merge code status of INSN to CODE.  */
-
-static void
-set_insn_status (rtx insn, enum insn_merge_code code)
-{
-  gcc_assert (INSN_UID (insn) < max_insn_uid);
-  is_insn_merge_attempted[INSN_UID (insn)] = code;
-}
-
-/* Given a insn (CURR_INSN) and a pointer to the SET rtx (ORIG_SET)
-   that needs to be modified, this code modifies the SET rtx to a
-   new SET rtx that zero_extends the right hand expression into a DImode
-   register (NEWREG) on the left hand side.  Note that multiple
-   assumptions are made about the nature of the set that needs
-   to be true for this to work and is called from merge_def_and_ze.
-
-   Original :
-   (set (reg:SI a) (expression))
-
-   Transform :
-   (set (reg:DI a) (zero_extend (expression)))
-
-   Special Cases :
-   If the expression is a constant or another zero_extend directly
-   assign it to the DI mode register.  */
-
-static bool
-combine_set_zero_extend (rtx curr_insn, rtx *orig_set, rtx newreg)
-{
-  rtx temp_extension, simplified_temp_extension, new_set, new_const_int;
-  rtx orig_src;
-  HOST_WIDE_INT val;
-  unsigned int mask, delta_width;
-
-  /* Change the SET rtx and validate it.  */
-  orig_src = SET_SRC (*orig_set);
-  new_set = NULL_RTX;
-
-  /* The right hand side can also be VOIDmode.  These cases have to be
-     handled differently.  */
-
-  if (GET_MODE (orig_src) != SImode)
-    {
-      /* Merge constants by directly moving the constant into the
-         DImode register under some conditions.  */
-
-      if (GET_CODE (orig_src) == CONST_INT
-	  && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (SImode))
-        {
-          if (INTVAL (orig_src) >= 0)
-            new_set = gen_rtx_SET (VOIDmode, newreg, orig_src);
-          else if (INTVAL (orig_src) < 0)
-            {
-              /* Zero-extending a negative SImode integer into DImode
-                 makes it a positive integer.  Convert the given negative
-                 integer into the appropriate integer when zero-extended.  */
-
-              delta_width = HOST_BITS_PER_WIDE_INT - GET_MODE_BITSIZE (SImode);
-              mask = (~(unsigned HOST_WIDE_INT) 0) >> delta_width;
-              val = INTVAL (orig_src);
-              val = val & mask;
-              new_const_int = gen_rtx_CONST_INT (VOIDmode, val);
-              new_set = gen_rtx_SET (VOIDmode, newreg, new_const_int);
-            }
-          else
-            return false;
-        }
-      else
-        {
-          /* This is mostly due to a call insn that should not be
-             optimized.  */
-
-          return false;
-        }
-    }
-  else if (GET_CODE (orig_src) == ZERO_EXTEND)
-    {
-      /* Here a zero-extend is used to get to SI. Why not make it
-         all the  way till DI.  */
-
-      temp_extension = gen_rtx_ZERO_EXTEND (DImode, XEXP (orig_src, 0));
-      simplified_temp_extension = simplify_rtx (temp_extension);
-      if (simplified_temp_extension)
-        temp_extension = simplified_temp_extension;
-      new_set = gen_rtx_SET (VOIDmode, newreg, temp_extension);
-    }
-  else if (GET_CODE (orig_src) == IF_THEN_ELSE)
-    {
-      /* Only IF_THEN_ELSE of phi-type copies are combined. Otherwise,
-         in general, IF_THEN_ELSE should not be combined.  */
-
-      return false;
-    }
-  else
-    {
-      /* This is the normal case we expect.  */
-
-      temp_extension = gen_rtx_ZERO_EXTEND (DImode, orig_src);
-      simplified_temp_extension = simplify_rtx (temp_extension);
-      if (simplified_temp_extension)
-        temp_extension = simplified_temp_extension;
-      new_set = gen_rtx_SET (VOIDmode, newreg, temp_extension);
-    }
-
-  gcc_assert (new_set != NULL_RTX);
-
-  /* This change is a part of a group of changes. Hence,
-     validate_change will not try to commit the change.  */
-
-  if (validate_change (curr_insn, orig_set, new_set, true))
-    {
-      if (dump_file)
-        {
-          fprintf (dump_file, "Merged Instruction with ZERO_EXTEND:\n");
-          print_rtl_single (dump_file, curr_insn);
-        }
-      return true;
-    }
-  return false;
-}
-
-/* This returns the DI mode for the SI register REG_SI.  */
-
-static rtx
-get_reg_di (rtx reg_si)
-{
-  rtx newreg;
-
-  newreg = gen_rtx_REG (DImode, REGNO (reg_si));
-  gcc_assert (newreg);
-  return newreg;
-}
-
-/* Treat if_then_else insns, where the operands of both branches
-   are registers, as copies. For instance,
-   Original :
-   (set (reg:SI a) (if_then_else (cond) (reg:SI b) (reg:SI c)))
-   Transformed :
-   (set (reg:DI a) (if_then_else (cond) (reg:DI b) (reg:DI c)))
-   DEF_INSN is the if_then_else insn.  */
-
-static bool
-transform_ifelse (rtx def_insn)
-{
-  rtx set_insn = PATTERN (def_insn);
-  rtx srcreg, dstreg, srcreg2;
-  rtx map_srcreg, map_dstreg, map_srcreg2;
-  rtx ifexpr;
-  rtx cond;
-  rtx new_set;
-
-  gcc_assert (GET_CODE (set_insn) == SET);
-  cond = XEXP (SET_SRC (set_insn), 0);
-  dstreg = SET_DEST (set_insn);
-  srcreg = XEXP (SET_SRC (set_insn), 1);
-  srcreg2 = XEXP (SET_SRC (set_insn), 2);
-  map_srcreg = get_reg_di (srcreg);
-  map_srcreg2 = get_reg_di (srcreg2);
-  map_dstreg = get_reg_di (dstreg);
-  ifexpr = gen_rtx_IF_THEN_ELSE (DImode, cond, map_srcreg, map_srcreg2);
-  new_set = gen_rtx_SET (VOIDmode, map_dstreg, ifexpr);
-
-  if (validate_change (def_insn, &PATTERN (def_insn), new_set, true))
-    {
-      if (dump_file)
-        {
-          fprintf (dump_file, "Cond_Move Instruction's mode extended :\n");
-          print_rtl_single (dump_file, def_insn);
-        }
-      return true;
-    }
-  else
-    return false;
-}
-
-/* Function to get all the immediate definitions of an instruction.
-   The reaching definitions are desired for WHICH_REG used in
-   CURR_INSN.  This function returns 0 if there was an error getting
-   a definition.  Upon success, this function returns the number of
-   definitions and stores the definitions in DEST.  */
-
-static int
-get_defs (rtx curr_insn, rtx which_reg, VEC (rtx,heap) **dest)
-{
-  df_ref reg_info, *defs;
-  struct df_link *def_chain;
-  int n_refs = 0;
-
-  defs = DF_INSN_USES (curr_insn);
-  reg_info = NULL;
-
-  while (*defs)
-    {
-      reg_info = *defs;
-      if (GET_CODE (DF_REF_REG (reg_info)) == SUBREG)
-        return 0;
-      if (REGNO (DF_REF_REG (reg_info)) == REGNO (which_reg))
-        break;
-      defs++;
-    }
-
-  gcc_assert (reg_info != NULL && defs != NULL);
-  def_chain = DF_REF_CHAIN (reg_info);
-
-  while (def_chain)
-    {
-      /* Problem getting some definition for this instruction.  */
-
-      if (def_chain->ref == NULL)
-        return 0;
-      if (DF_REF_INSN_INFO (def_chain->ref) == NULL)
-        return 0;
-      def_chain = def_chain->next;
-    }
-
-  def_chain = DF_REF_CHAIN (reg_info);
-
-  if (dest == NULL)
-    return 1;
-
-  while (def_chain)
-    {
-      VEC_safe_push (rtx, heap, *dest, DF_REF_INSN (def_chain->ref));
-      def_chain = def_chain->next;
-      n_refs++;
-    }
-  return n_refs;
-}
-
-/* rtx function to check if this SET insn, EXPR, is a conditional copy insn :
-   (set (reg:SI a ) (IF_THEN_ELSE (cond) (reg:SI b) (reg:SI c)))
-   Called from is_insn_cond_copy.  DATA stores the two registers on each
-   side of the condition.  */
-
-static int
-is_this_a_cmove (rtx expr, void *data)
-{
-  /* Check for conditional (if-then-else) copy.  */
-
-  if (GET_CODE (expr) == SET
-      && GET_CODE (SET_DEST (expr)) == REG
-      && GET_MODE (SET_DEST (expr)) == SImode
-      && GET_CODE (SET_SRC (expr))  == IF_THEN_ELSE
-      && GET_CODE (XEXP (SET_SRC (expr), 1)) == REG
-      && GET_MODE (XEXP (SET_SRC (expr), 1)) == SImode
-      && GET_CODE (XEXP (SET_SRC (expr), 2)) == REG
-      && GET_MODE (XEXP (SET_SRC (expr), 2)) == SImode)
-    {
-      ((rtx *)data)[0] = XEXP (SET_SRC (expr), 1);
-      ((rtx *)data)[1] = XEXP (SET_SRC (expr), 2);
-      return 1;
-    }
-  return 0;
-}
-
-/* This returns 1 if it found
-   (SET (reg:SI REGNO (def_reg)) (if_then_else (cond) (REG:SI x1) (REG:SI x2)))
-   in the DEF_INSN pattern.  It stores the x1 and x2 in COPY_REG_1
-   and COPY_REG_2.  */
-
-static int
-is_insn_cond_copy (rtx def_insn, rtx *copy_reg_1, rtx *copy_reg_2)
-{
-  int type;
-  rtx set_expr;
-  rtx srcreg[2];
-
-  srcreg[0] = NULL_RTX;
-  srcreg[1] = NULL_RTX;
-
-  set_expr = single_set (def_insn);
-
-  if (set_expr == NULL_RTX)
-    return 0;
-
-  type = is_this_a_cmove (set_expr, (void *) srcreg);
-
-  if (type)
-    {
-      *copy_reg_1 = srcreg[0];
-      *copy_reg_2 = srcreg[1];
-      return type;
-    }
-
-  return 0;
-}
-
-/* Reaching Definitions of the zero-extended register could be conditional
-   copies or regular definitions.  This function separates the two types into
-   two lists, DEFS_LIST and COPIES_LIST.  This is necessary because, if a
-   reaching definition is a conditional copy, combining the zero_extend with
-   this definition is wrong.  Conditional copies are merged by transitively
-   merging its definitions.  The defs_list is populated with all the reaching
-   definitions of the zero-extension instruction (ZERO_EXTEND_INSN) which must
-   be merged with a zero_extend.  The copies_list contains all the conditional
-   moves that will later be extended into a DI mode conditonal move if all the
-   merges are successful.  The function returns false when there is a failure
-   in getting some definitions, like that of parameters.  It returns 1 upon
-   success, 0 upon failure and 2 when all definitions of the ZERO_EXTEND_INSN
-   were merged previously.  */
-
-static int
-make_defs_and_copies_lists (rtx zero_extend_insn, rtx set_pat,
-                            VEC (rtx,heap) **defs_list,
-                            VEC (rtx,heap) **copies_list)
-{
-  bool *is_insn_visited;
-  VEC (rtx,heap) *work_list;
-  rtx srcreg, copy_reg_1, copy_reg_2;
-  rtx def_insn;
-  int n_defs = 0;
-  int vec_index = 0;
-  int n_worklist = 0;
-  int i, is_copy;
-
-  srcreg = XEXP (SET_SRC (set_pat), 0);
-  work_list = VEC_alloc (rtx, heap, 8);
-
-  /* Initialize the Work List */
-  n_worklist = get_defs (zero_extend_insn, srcreg, &work_list);
-
-  if (n_worklist == 0)
-    {
-      VEC_free (rtx, heap, work_list);
-      /* The number of defs being equal to zero can only imply that all of its
-         definitions have been previously merged.  */
-      return 2;
-    }
-
-  is_insn_visited = XNEWVEC (bool, max_insn_uid);
-
-  for (i = 0; i < max_insn_uid; i++)
-    is_insn_visited[i] = false;
-
-
-  /* Perform transitive closure for conditional copies.  */
-  while (n_worklist > vec_index)
-    {
-      def_insn = VEC_index (rtx, work_list, vec_index);
-      gcc_assert (INSN_UID (def_insn) < max_insn_uid);
-
-      if (is_insn_visited[INSN_UID (def_insn)])
-        {
-          vec_index++;
-          continue;
-        }
-
-      is_insn_visited[INSN_UID (def_insn)] = true;
-      copy_reg_1 = copy_reg_2 = NULL_RTX;
-      is_copy = is_insn_cond_copy (def_insn, &copy_reg_1, &copy_reg_2);
-      if (is_copy)
-        {
-          gcc_assert (copy_reg_1 && copy_reg_2);
-
-          /* Push it into the copy list first.  */
-
-          VEC_safe_push (rtx, heap, *copies_list, def_insn);
-
-          /* Perform transitive closure here */
-
-          n_defs = get_defs (def_insn, copy_reg_1, &work_list);
-
-          if (n_defs == 0)
-            {
-              VEC_free (rtx, heap, work_list);
-              XDELETEVEC (is_insn_visited);
-              return 0;
-            }
-          n_worklist += n_defs;
-
-          n_defs = get_defs (def_insn, copy_reg_2, &work_list);
-          if (n_defs == 0)
-            {
-              VEC_free (rtx, heap, work_list);
-              XDELETEVEC (is_insn_visited);
-              return 0;
-            }
-          n_worklist += n_defs;
-        }
-      else
-        {
-          VEC_safe_push (rtx, heap, *defs_list, def_insn);
-        }
-      vec_index++;
-    }
-
-  VEC_free (rtx, heap, work_list);
-  XDELETEVEC (is_insn_visited);
-  return 1;
-}
-
-/* Merge the DEF_INSN with a zero-extend.  Calls combine_set_zero_extend
-   on the SET pattern.  */
-
-static bool
-merge_def_and_ze (rtx def_insn)
-{
-  enum rtx_code code;
-  rtx setreg;
-  rtx *sub_rtx;
-  rtx s_expr;
-  int i;
-
-  code = GET_CODE (PATTERN (def_insn));
-  sub_rtx = NULL;
-
-  if (code == PARALLEL)
-    {
-      for (i = 0; i < XVECLEN (PATTERN (def_insn), 0); i++)
-        {
-          s_expr = XVECEXP (PATTERN (def_insn), 0, i);
-          if (GET_CODE (s_expr) != SET)
-            continue;
-
-          if (sub_rtx == NULL)
-            sub_rtx = &XVECEXP (PATTERN (def_insn), 0, i);
-          else
-            {
-              /* PARALLEL with multiple SETs.  */
-              return false;
-            }
-        }
-    }
-  else if (code == SET)
-    sub_rtx = &PATTERN (def_insn);
-  else
-    {
-      /* It is not a PARALLEL or a SET, what could it be ? */
-      return false;
-    }
-
-  gcc_assert (sub_rtx != NULL);
-
-  if (GET_CODE (SET_DEST (*sub_rtx)) == REG
-      && GET_MODE (SET_DEST (*sub_rtx)) == SImode)
-    {
-      setreg = get_reg_di (SET_DEST (*sub_rtx));
-      return combine_set_zero_extend (def_insn, sub_rtx, setreg);
-    }
-  else
-    return false;
-  return true;
-}
-
-/* This function goes through all reaching defs of the source
-   of the zero extension instruction (ZERO_EXTEND_INSN) and
-   tries to combine the zero extension with the definition
-   instruction.  The changes are made as a group so that even
-   if one definition cannot be merged, all reaching definitions
-   end up not being merged. When a conditional copy is encountered,
-   merging is attempted transitively on its definitions.  It returns
-   true upon success and false upon failure.  */
-
-static bool
-combine_reaching_defs (rtx zero_extend_insn, rtx set_pat)
-{
-  rtx def_insn;
-  bool merge_successful = true;
-  int i;
-  int defs_ix;
-  int outcome;
-
-  /* To store the definitions that have been merged.  */
-
-  VEC (rtx, heap) *defs_list, *copies_list, *vec;
-  enum insn_merge_code merge_code;
-
-  defs_list = VEC_alloc (rtx, heap, 8);
-  copies_list = VEC_alloc (rtx, heap, 8);
-
-  outcome = make_defs_and_copies_lists (zero_extend_insn,
-                                        set_pat, &defs_list, &copies_list);
-
-  /* outcome == 2 implies that all the definitions for this zero_extend were
-     merged while previously when handling other zero_extends.  */
-
-  if (outcome == 2)
-    {
-      VEC_free (rtx, heap, defs_list);
-      VEC_free (rtx, heap, copies_list);
-      if (dump_file)
-        fprintf (dump_file, "All definitions have been merged previously.\n");
-      return true;
-    }
-
-  if (outcome == 0)
-    {
-      VEC_free (rtx, heap, defs_list);
-      VEC_free (rtx, heap, copies_list);
-      return false;
-    }
-
-  merge_successful = true;
-
-  /* Go through the defs vector and try to merge all the definitions
-     in this vector.  */
-
-  vec = VEC_alloc (rtx, heap, 8);
-  FOR_EACH_VEC_ELT (rtx, defs_list, defs_ix, def_insn)
-    {
-      merge_code = get_insn_status (def_insn);
-      gcc_assert (merge_code == MERGE_NOT_ATTEMPTED);
-
-      if (merge_def_and_ze (def_insn))
-        VEC_safe_push (rtx, heap, vec, def_insn);
-      else
-        {
-          merge_successful = false;
-          break;
-        }
-    }
-
-  /* Now go through the conditional copies vector and try to merge all
-     the copies in this vector.  */
-
-  if (merge_successful)
-    {
-      FOR_EACH_VEC_ELT (rtx, copies_list, i, def_insn)
-        {
-          if (transform_ifelse (def_insn))
-            {
-              VEC_safe_push (rtx, heap, vec, def_insn);
-            }
-          else
-            {
-              merge_successful = false;
-              break;
-            }
-        }
-    }
-
-  if (merge_successful)
-    {
-      /* Commit the changes here if possible */
-      /* XXX : Now, it is an all or nothing scenario.  Even if one definition
-         cannot be merged we totally bail.  In future, allow zero-extensions to
-         be partially eliminated along those paths where the definitions could
-         be merged.  */
-
-      if (apply_change_group ())
-        {
-          if (dump_file)
-            fprintf (dump_file, "All merges were successful ....\n");
-
-          FOR_EACH_VEC_ELT (rtx, vec, i, def_insn)
-            {
-              set_insn_status (def_insn, MERGE_SUCCESS);
-            }
-
-          VEC_free (rtx, heap, vec);
-          VEC_free (rtx, heap, defs_list);
-          VEC_free (rtx, heap, copies_list);
-          return true;
-        }
-      else
-        {
-          /* Changes need not be cancelled explicitly as apply_change_group
-             does it.  Print list of definitions in the dump_file for debug
-             purposes.  This zero-extension cannot be deleted.  */
-
-          if (dump_file)
-            {
-              FOR_EACH_VEC_ELT (rtx, vec, i, def_insn)
-                {
-                  fprintf (dump_file, " Ummergable definitions : \n");
-                  print_rtl_single (dump_file, def_insn);
-                }
-            }
-        }
-    }
-  else
-    {
-      /* Cancel any changes that have been made so far.  */
-      cancel_changes (0);
-    }
-
-  VEC_free (rtx, heap, vec);
-  VEC_free (rtx, heap, defs_list);
-  VEC_free (rtx, heap, copies_list);
-  return false;
-}
-
-/* Carry information about zero-extensions while walking the RTL.  */
-
-struct zero_extend_info
-{
-  /* The insn where the zero-extension is.  */
-  rtx insn;
-
-  /* The list of candidates.  */
-  VEC (rtx, heap) *insn_list;
-};
-
-/* Add a zero-extend pattern that could be eliminated.  This is called via
-   note_stores from find_removable_zero_extends.  */
-
-static void
-add_removable_zero_extend (rtx x ATTRIBUTE_UNUSED, const_rtx expr, void *data)
-{
-  struct zero_extend_info *zei = (struct zero_extend_info *)data;
-  rtx src, dest;
-
-  /* We are looking for SET (REG:DI N) (ZERO_EXTEND (REG:SI N)).  */
-  if (GET_CODE (expr) != SET)
-    return;
-
-  src = SET_SRC (expr);
-  dest = SET_DEST (expr);
-
-  if (REG_P (dest)
-      && GET_MODE (dest) == DImode
-      && GET_CODE (src) == ZERO_EXTEND
-      && REG_P (XEXP (src, 0))
-      && GET_MODE (XEXP (src, 0)) == SImode
-      && REGNO (dest) == REGNO (XEXP (src, 0)))
-    {
-      if (get_defs (zei->insn, XEXP (src, 0), NULL))
-	VEC_safe_push (rtx, heap, zei->insn_list, zei->insn);
-      else if (dump_file)
-	{
-	  fprintf (dump_file, "Cannot eliminate zero-extension: \n");
-	  print_rtl_single (dump_file, zei->insn);
-	  fprintf (dump_file, "No defs. Could be extending parameters.\n");
-	}
-    }
-}
-
-/* Traverse the instruction stream looking for zero-extends and return the
-   list of candidates.  */
-
-static VEC (rtx,heap)*
-find_removable_zero_extends (void)
-{
-  struct zero_extend_info zei;
-  basic_block bb;
-  rtx insn;
-
-  zei.insn_list = VEC_alloc (rtx, heap, 8);
-
-  FOR_EACH_BB (bb)
-    FOR_BB_INSNS (bb, insn)
-      {
-	if (!NONDEBUG_INSN_P (insn))
-	  continue;
-
-	zei.insn = insn;
-	note_stores (PATTERN (insn), add_removable_zero_extend, &zei);
-      }
-
-  return zei.insn_list;
-}
-
-/* This is the main function that checks the insn stream for redundant
-   zero extensions and tries to remove them if possible.  */
-
-static unsigned int
-find_and_remove_ze (void)
-{
-  rtx curr_insn = NULL_RTX;
-  int i;
-  int ix;
-  long num_realized = 0;
-  long num_ze_opportunities = 0;
-  VEC (rtx, heap) *zeinsn_list;
-  VEC (rtx, heap) *zeinsn_del_list;
-
-  /* Construct DU chain to get all reaching definitions of each
-     zero-extension instruction.  */
-
-  df_chain_add_problem (DF_UD_CHAIN + DF_DU_CHAIN);
-  df_analyze ();
-
-  max_insn_uid = get_max_uid ();
-
-  is_insn_merge_attempted
-    = XNEWVEC (enum insn_merge_code,
-	       sizeof (enum insn_merge_code) * max_insn_uid);
-
-  for (i = 0; i < max_insn_uid; i++)
-    is_insn_merge_attempted[i] = MERGE_NOT_ATTEMPTED;
-
-  num_ze_opportunities = num_realized = 0;
-
-  zeinsn_del_list = VEC_alloc (rtx, heap, 4);
-
-  zeinsn_list = find_removable_zero_extends ();
-
-  FOR_EACH_VEC_ELT (rtx, zeinsn_list, ix, curr_insn)
-    {
-      num_ze_opportunities++;
-      /* Try to combine the zero-extends with the definition here.  */
-
-      if (dump_file)
-        {
-          fprintf (dump_file, "Trying to eliminate zero extension : \n");
-          print_rtl_single (dump_file, curr_insn);
-        }
-
-      if (combine_reaching_defs (curr_insn, PATTERN (curr_insn)))
-        {
-          if (dump_file)
-            fprintf (dump_file, "Eliminated the zero extension...\n");
-          num_realized++;
-          VEC_safe_push (rtx, heap, zeinsn_del_list, curr_insn);
-        }
-    }
-
-  /* Delete all useless zero extensions here in one sweep.  */
-  FOR_EACH_VEC_ELT (rtx, zeinsn_del_list, ix, curr_insn)
-    delete_insn (curr_insn);
-
-  free (is_insn_merge_attempted);
-  VEC_free (rtx, heap, zeinsn_list);
-  VEC_free (rtx, heap, zeinsn_del_list);
-
-  if (dump_file && num_ze_opportunities > 0)
-    fprintf (dump_file, "\n %s : num_zee_opportunities = %ld"
-			" num_realized = %ld\n",
-                        current_function_name (), num_ze_opportunities,
-                        num_realized);
-
-  df_finish_pass (false);
-  return 0;
-}
-
-/* Find and remove redundant zero extensions.  */
-
-static unsigned int
-rest_of_handle_zee (void)
-{
-  timevar_push (TV_ZEE);
-  find_and_remove_ze ();
-  timevar_pop (TV_ZEE);
-  return 0;
-}
-
-/* Run zee pass when flag_zee is set at optimization level > 0.  */
-
-static bool
-gate_handle_zee (void)
-{
-  return (optimize > 0 && flag_zee);
-}
-
-struct rtl_opt_pass pass_implicit_zee =
-{
- {
-  RTL_PASS,
-  "zee",                                /* name */
-  gate_handle_zee,                      /* gate */
-  rest_of_handle_zee,                   /* execute */
-  NULL,                                 /* sub */
-  NULL,                                 /* next */
-  0,                                    /* static_pass_number */
-  TV_ZEE,                               /* tv_id */
-  0,                                    /* properties_required */
-  0,                                    /* properties_provided */
-  0,                                    /* properties_destroyed */
-  0,                                    /* todo_flags_start */
-  TODO_ggc_collect |
-  TODO_verify_rtl_sharing,              /* todo_flags_finish */
- }
-};