toolchain/gcc/patches/3.4.6/601-gcc34-arm-ldm.patch

   1 --- gcc-3.4.0/gcc/config/arm/arm.c.arm-ldm      2004-02-27 09:51:05.000000000 -0500
   2 +++ gcc-3.4.0/gcc/config/arm/arm.c      2004-04-24 18:16:25.000000000 -0400
   3 @@ -8520,6 +8520,26 @@
   4    return_used_this_function = 0;
   5  }
   6
   7 +/* Return the number (counting from 0) of
   8 +   the least significant set bit in MASK.  */
   9 +
  10 +#ifdef __GNUC__
  11 +inline
  12 +#endif
  13 +static int
  14 +number_of_first_bit_set (mask)
  15 +     int mask;
  16 +{
  17 +  int bit;
  18 +
  19 +  for (bit = 0;
  20 +       (mask & (1 << bit)) == 0;
  21 +       ++bit)
  22 +    continue;
  23 +
  24 +  return bit;
  25 +}
  26 +
  27  const char *
  28  arm_output_epilogue (rtx sibling)
  29  {
  30 @@ -8753,27 +8773,47 @@
  31           saved_regs_mask |=   (1 << PC_REGNUM);
  32         }
  33
  34 -      /* Load the registers off the stack.  If we only have one register
  35 -        to load use the LDR instruction - it is faster.  */
  36 -      if (saved_regs_mask == (1 << LR_REGNUM))
  37 -       {
  38 -         /* The exception handler ignores the LR, so we do
  39 -            not really need to load it off the stack.  */
  40 -         if (eh_ofs)
  41 -           asm_fprintf (f, "\tadd\t%r, %r, #4\n", SP_REGNUM, SP_REGNUM);
  42 -         else
  43 -           asm_fprintf (f, "\tldr\t%r, [%r], #4\n", LR_REGNUM, SP_REGNUM);
  44 -       }
  45 -      else if (saved_regs_mask)
  46 +      if (saved_regs_mask)
  47         {
  48 -         if (saved_regs_mask & (1 << SP_REGNUM))
  49 -           /* Note - write back to the stack register is not enabled
  50 -              (ie "ldmfd sp!...").  We know that the stack pointer is
  51 -              in the list of registers and if we add writeback the
  52 -              instruction becomes UNPREDICTABLE.  */
  53 -           print_multi_reg (f, "ldmfd\t%r", SP_REGNUM, saved_regs_mask);
  54 +         /* Load the registers off the stack.  If we only have one register
  55 +            to load use the LDR instruction - it is faster.  */
  56 +         if (bit_count (saved_regs_mask) == 1)
  57 +           {
  58 +             int reg = number_of_first_bit_set (saved_regs_mask);
  59 +
  60 +             switch (reg)
  61 +               {
  62 +               case SP_REGNUM:
  63 +                 /* Mustn't use base writeback when loading SP.  */
  64 +                 asm_fprintf (f, "\tldr\t%r, [%r]\n", SP_REGNUM, SP_REGNUM);
  65 +                 break;
  66 +
  67 +               case LR_REGNUM:
  68 +                 if (eh_ofs)
  69 +                   {
  70 +                     /* The exception handler ignores the LR, so we do
  71 +                        not really need to load it off the stack.  */
  72 +                     asm_fprintf (f, "\tadd\t%r, %r, #4\n", SP_REGNUM, SP_REGNUM);
  73 +                     break;
  74 +                   }
  75 +                 /* else fall through */
  76 +
  77 +               default:
  78 +                 asm_fprintf (f, "\tldr\t%r, [%r], #4\n", reg, SP_REGNUM);
  79 +                 break;
  80 +               }
  81 +           }
  82           else
  83 -           print_multi_reg (f, "ldmfd\t%r!", SP_REGNUM, saved_regs_mask);
  84 +           {
  85 +             if (saved_regs_mask & (1 << SP_REGNUM))
  86 +               /* Note - write back to the stack register is not enabled
  87 +                  (ie "ldmfd sp!...").  We know that the stack pointer is
  88 +                  in the list of registers and if we add writeback the
  89 +                  instruction becomes UNPREDICTABLE.  */
  90 +               print_multi_reg (f, "ldmfd\t%r", SP_REGNUM, saved_regs_mask);
  91 +             else
  92 +               print_multi_reg (f, "ldmfd\t%r!", SP_REGNUM, saved_regs_mask);
  93 +           }
  94         }
  95
  96        if (current_function_pretend_args_size)
  97 @@ -11401,22 +11441,6 @@
  98      }
  99  }
 100
 101 -/* Return the number (counting from 0) of
 102 -   the least significant set bit in MASK.  */
 103 -
 104 -inline static int
 105 -number_of_first_bit_set (int mask)
 106 -{
 107 -  int bit;
 108 -
 109 -  for (bit = 0;
 110 -       (mask & (1 << bit)) == 0;
 111 -       ++bit)
 112 -    continue;
 113 -
 114 -  return bit;
 115 -}
 116 -
 117  /* Generate code to return from a thumb function.
 118     If 'reg_containing_return_addr' is -1, then the return address is
 119     actually on the stack, at the stack pointer.  */