1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/patches/gcc/4.2.0/904-flatten-switch-stmt-00.patch	Sat Jul 14 13:04:51 2007 +0000
     1.3 @@ -0,0 +1,153 @@
     1.4 +Hi,
     1.5 +
     1.6 +The attached patch makes sure that we create smaller object code for
     1.7 +simple switch statements. We just make sure to flatten the switch
     1.8 +statement into an if-else chain, basically.
     1.9 +
    1.10 +This fixes a size-regression as compared to gcc-3.4, as can be seen
    1.11 +below.
    1.12 +
    1.13 +2007-04-15  Bernhard Fischer  <..>
    1.14 +
    1.15 +	* stmt.c (expand_case): Do not create a complex binary tree when
    1.16 +	optimizing for size but rather use the simple ordered list.
    1.17 +	(emit_case_nodes): do not emit jumps to the default_label when
    1.18 +	optimizing for size.
    1.19 +
    1.20 +Not regtested so far.
    1.21 +Comments?
    1.22 +
    1.23 +Attached is the test switch.c mentioned below.
    1.24 +
    1.25 +$ for i in 2.95 3.3 3.4 4.0 4.1 4.2.orig-HEAD 4.3.orig-HEAD 4.3-HEAD;do
    1.26 +gcc-$i  -DCHAIN -Os -o switch-CHAIN-$i.o -c switch.c ;done
    1.27 +$ for i in 2.95 3.3 3.4 4.0 4.1 4.2.orig-HEAD 4.3.orig-HEAD 4.3-HEAD;do
    1.28 +gcc-$i  -UCHAIN -Os -o switch-$i.o -c switch.c ;done
    1.29 +
    1.30 +$ size switch-*.o
    1.31 +   text	   data	    bss	    dec	    hex	filename
    1.32 +    169	      0	      0	    169	     a9	switch-2.95.o
    1.33 +    115	      0	      0	    115	     73	switch-3.3.o
    1.34 +    103	      0	      0	    103	     67	switch-3.4.o
    1.35 +    124	      0	      0	    124	     7c	switch-4.0.o
    1.36 +    124	      0	      0	    124	     7c	switch-4.1.o
    1.37 +    124	      0	      0	    124	     7c	switch-4.2.orig-HEAD.o
    1.38 +     95	      0	      0	     95	     5f	switch-4.3-HEAD.o
    1.39 +    124	      0	      0	    124	     7c	switch-4.3.orig-HEAD.o
    1.40 +    166	      0	      0	    166	     a6	switch-CHAIN-2.95.o
    1.41 +    111	      0	      0	    111	     6f	switch-CHAIN-3.3.o
    1.42 +     95	      0	      0	     95	     5f	switch-CHAIN-3.4.o
    1.43 +     95	      0	      0	     95	     5f	switch-CHAIN-4.0.o
    1.44 +     95	      0	      0	     95	     5f	switch-CHAIN-4.1.o
    1.45 +     95	      0	      0	     95	     5f	switch-CHAIN-4.2.orig-HEAD.o
    1.46 +     95	      0	      0	     95	     5f	switch-CHAIN-4.3-HEAD.o
    1.47 +     95	      0	      0	     95	     5f	switch-CHAIN-4.3.orig-HEAD.o
    1.48 +
    1.49 +
    1.50 +Content-Type: text/x-diff; charset=us-ascii
    1.51 +Content-Disposition: attachment; filename="gcc-4.3.gcc-flatten-switch-stmt.00.diff"
    1.52 +
    1.53 +Index: gcc-4.2.0/gcc/stmt.c
    1.54 +===================================================================
    1.55 +--- gcc-4.2.0.orig/gcc/stmt.c	(revision 123843)
    1.56 ++++ gcc-4.2.0/gcc/stmt.c	(working copy)
    1.57 +@@ -2517,7 +2517,11 @@ expand_case (tree exp)
    1.58 + 	  use_cost_table
    1.59 + 	    = (TREE_CODE (orig_type) != ENUMERAL_TYPE
    1.60 + 	       && estimate_case_costs (case_list));
    1.61 +-	  balance_case_nodes (&case_list, NULL);
    1.62 ++	  /* When optimizing for size, we want a straight list to avoid
    1.63 ++	     jumps as much as possible. This basically creates an if-else
    1.64 ++	     chain.  */
    1.65 ++	  if (!optimize_size)
    1.66 ++	    balance_case_nodes (&case_list, NULL);
    1.67 + 	  emit_case_nodes (index, case_list, default_label, index_type);
    1.68 + 	  emit_jump (default_label);
    1.69 + 	}
    1.70 +@@ -3075,6 +3079,7 @@ emit_case_nodes (rtx index, case_node_pt
    1.71 + 	    {
    1.72 + 	      if (!node_has_low_bound (node, index_type))
    1.73 + 		{
    1.74 ++		  if (!optimize_size) /* don't jl to the .default_label. */
    1.75 + 		  emit_cmp_and_jump_insns (index,
    1.76 + 					   convert_modes
    1.77 + 					   (mode, imode,
    1.78 +
    1.79 +
    1.80 +Content-Type: text/x-csrc; charset=us-ascii
    1.81 +Content-Disposition: attachment; filename="switch.c"
    1.82 +
    1.83 +int
    1.84 +commutative_tree_code (int code)
    1.85 +{
    1.86 +#define CASE(val, ret) case val:/* __asm__("# val="#val ",ret="#ret);*/ return ret;
    1.87 +#ifndef CHAIN
    1.88 +  switch (code)
    1.89 +    {
    1.90 +# if 1
    1.91 +  CASE(1,3)
    1.92 +  CASE(3,2)
    1.93 +  CASE(5,8)
    1.94 +  CASE(7,1)
    1.95 +  CASE(33,4)
    1.96 +  CASE(44,9)
    1.97 +  CASE(55,10)
    1.98 +  CASE(66,-1)
    1.99 +  CASE(77,99)
   1.100 +  CASE(666,0)
   1.101 +# else
   1.102 +    case 1:
   1.103 +      return 3;
   1.104 +    case 3:
   1.105 +      return 2;
   1.106 +    case 5:
   1.107 +      return 8;
   1.108 +    case 7:
   1.109 +      return 1;
   1.110 +    case 33:
   1.111 +      return 4;
   1.112 +    case 44:
   1.113 +      return 9;
   1.114 +    case 55:
   1.115 +      return 10;
   1.116 +    case 66:
   1.117 +      return -1;
   1.118 +    case 77:
   1.119 +      return 99;
   1.120 +    case 666:
   1.121 +      return 0;
   1.122 +# endif
   1.123 +    default:
   1.124 +      break;
   1.125 +    }
   1.126 +  return 4711;
   1.127 +
   1.128 +#else
   1.129 +   if (code == 1)
   1.130 +	return 3;
   1.131 +  else if (code == 3)
   1.132 +	return 2;
   1.133 +  else if (code == 5)
   1.134 +	return 8;
   1.135 +  else if (code == 7)
   1.136 +	return 1;
   1.137 +  else if (code == 33)
   1.138 +	return 4;
   1.139 +  else if (code == 44)
   1.140 +	return 9;
   1.141 +  else if (code == 55)
   1.142 +	return 10;
   1.143 +  else if (code == 66)
   1.144 +	return -1;
   1.145 +  else if (code == 77)
   1.146 +	return 99;
   1.147 +  else if (code == 666)
   1.148 +	return 0;
   1.149 +  else
   1.150 +	return 4711;
   1.151 +#endif
   1.152 +}
   1.153 +
   1.154 +
   1.155 +--AhhlLboLdkugWU4S--
   1.156 +