builtins.c (expand_builtin_strlen): Be prepared for strlensi to fail.

        * builtins.c (expand_builtin_strlen): Be prepared for strlensi
        to fail.  Don't pre-expand the source operand.

From-SVN: r32429

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4b36c413815347a15dc374145bd385d60129993f..b3a8130d86c7e4821c0bca2b30ecfbf3773f66b4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2000-03-08  Richard Henderson  <rth@cygnus.com>
+
+       * builtins.c (expand_builtin_strlen): Be prepared for strlensi
+       to fail.  Don't pre-expand the source operand.
+
+       * i386.md (strlensi): Initialize eoschar and align before use.
+
 2000-03-08  Jason Merrill  <jason@casey.cygnus.com>
 
        * expr.c (expand_expr, case ARRAY_REF): Still check for missing

diff --git a/gcc/builtins.c b/gcc/builtins.c
index a38f3c4b861b052f315b567a0589b667c944d22b..c75d2fb44ae10bc35000fa36fd8a1e9e3fa2b144 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -1334,13 +1334,14 @@ expand_builtin_strlen (exp, target, mode)
     return 0;
   else
     {
+      rtx pat;
       tree src = TREE_VALUE (arglist);
       tree len = c_strlen (src);
 
       int align
        = get_pointer_alignment (src, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
 
-      rtx result, src_rtx, char_rtx;
+      rtx result, src_reg, char_rtx, before_strlen;
       enum machine_mode insn_mode = value_mode, char_mode;
       enum insn_code icode = CODE_FOR_nothing;
 
@@ -1352,8 +1353,7 @@ expand_builtin_strlen (exp, target, mode)
       if (align == 0)
        return 0;
 
-      /* Call a function if we can't compute strlen in the right mode.  */
-
+      /* Bail out if we can't compute strlen in the right mode.  */
       while (insn_mode != VOIDmode)
        {
          icode = strlen_optab->handlers[(int) insn_mode].insn_code;
@@ -1373,21 +1373,19 @@ expand_builtin_strlen (exp, target, mode)
             && REGNO (result) >= FIRST_PSEUDO_REGISTER))
        result = gen_reg_rtx (insn_mode);
 
-      /* Make sure the operands are acceptable to the predicates.  */
-
-      if (! (*insn_data[(int)icode].operand[0].predicate) (result, insn_mode))
-       result = gen_reg_rtx (insn_mode);
-      src_rtx = memory_address (BLKmode,
-                               expand_expr (src, NULL_RTX, ptr_mode,
-                                            EXPAND_NORMAL));
+      /* Make a place to hold the source address.  We will not expand
+        the actual source until we are sure that the expansion will
+        not fail -- there are trees that cannot be expanded twice.  */
+      src_reg = gen_reg_rtx (Pmode);
 
-      if (! (*insn_data[(int)icode].operand[1].predicate) (src_rtx, Pmode))
-       src_rtx = copy_to_mode_reg (Pmode, src_rtx);
+      /* Mark the beginning of the strlen sequence so we can emit the
+        source operand later.  */
+      before_strlen = get_last_insn();
 
       /* Check the string is readable and has an end.  */
       if (current_function_check_memory_usage)
        emit_library_call (chkr_check_str_libfunc, 1, VOIDmode, 2,
-                          src_rtx, Pmode,
+                          src_reg, Pmode,
                           GEN_INT (MEMORY_USE_RO),
                           TYPE_MODE (integer_type_node));
 
@@ -1396,20 +1394,30 @@ expand_builtin_strlen (exp, target, mode)
       if (! (*insn_data[(int)icode].operand[2].predicate) (char_rtx, char_mode))
        char_rtx = copy_to_mode_reg (char_mode, char_rtx);
 
-      emit_insn (GEN_FCN (icode) (result,
-                                 gen_rtx_MEM (BLKmode, src_rtx),
-                                 char_rtx, GEN_INT (align)));
+      pat = GEN_FCN (icode) (result, gen_rtx_MEM (BLKmode, src_reg),
+                            char_rtx, GEN_INT (align));
+      if (! pat)
+       return 0;
+      emit_insn (pat);
+
+      /* Now that we are assured of success, expand the source.  */
+      start_sequence ();
+      pat = expand_expr (src, src_reg, ptr_mode, EXPAND_SUM);
+      if (pat != src_reg)
+       emit_move_insn (src_reg, pat);
+      pat = gen_sequence ();
+      end_sequence ();
+      emit_insn_after (pat, before_strlen);
 
       /* Return the value in the proper mode for this function.  */
       if (GET_MODE (result) == value_mode)
-       return result;
+       target = result;
       else if (target != 0)
-       {
-         convert_move (target, result, 0);
-         return target;
-       }
+       convert_move (target, result, 0);
       else
-       return convert_to_mode (value_mode, result, 0);
+       target = convert_to_mode (value_mode, result, 0);
+
+      return target;
     }
 }