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genattrab.c generate switch

Message ID 56AF9FE2.9050209@gmail.com
State New
Headers show

Commit Message

Jesper Broge Jørgensen Feb. 1, 2016, 6:11 p.m. UTC
On 19/01/16 13:18, Bernd Schmidt wrote:
> On 01/18/2016 11:44 PM, Jesper Broge Jørgensen wrote:
>> I found a formatting tool called uncrustify that comes with a gnu style
>> config
>> https://github.com/bengardner/uncrustify/blob/master/etc/gnu-indent.cfg
>> that needed a few tweaks to format code that looked what is already in
>> gcc/genattrtab.c
>>
>> The tweaks was:
>>
>> indent_with_tabs = 2 // instead of 0
>> sp_func_def_paren     = add // instead of remove
>> sp_func_proto_paren  = add // instead of remove
>> sp_func_call_paren     = add // instead of remove
>>
>> So now the code should be correctly formatted.
>
> Best to get that right when editing, though. emacs defaults to GNU 
> style and other editors can also be tweaked.
>
>> Do i send in a new patch or just respond to the old one with the new
>> changes?
>
> Usually best to send updated patches (as text/plain attachment to 
> avoid word-wrapping and other whitespace damage).
>
>> I have also followed instructions at
>> https://gcc.gnu.org/ml/gcc/2003-06/txt00010.txt to get copyright
>> assignment though i have not yet received a reply.
>
> Ok, we'll have to wait for that.
>
>
> Bernd
>
I have finally received the copyright assignment it is currently on its 
way over the atlantic via snail mail.
In the meantime i have attached the the refomatted patch here hoping it 
could be reviewed while we wait.
gcc/ChangeLog:

2016-01-19  Jesper Broge Jørgensen  <jesperbroge@gmail.com>

	* genattrtab.c (check_attr_set_switch): New function
	(write_attr_set): Write a switch instead of if condition if possible
diff mbox

Patch

diff --git a/gcc/genattrtab.c b/gcc/genattrtab.c
index 2caf8f6..8e7f9e6 100644
--- a/gcc/genattrtab.c
+++ b/gcc/genattrtab.c
@@ -4113,6 +4113,103 @@  eliminate_known_true (rtx known_true, rtx exp, int insn_code, int insn_index)
   return exp;
 }
 
+/* Check if exp contains a series of IOR conditions on the same attr_name.
+   If it does it can be turned into a switch statement and returns true.
+   If write_cases is true it will write the cases of the switch to outf.  */
+
+static int
+check_attr_set_switch (FILE *outf, rtx exp, unsigned int attrs_cached,
+		       int write_cases, int indent)
+{
+  if (GET_CODE (exp) != IOR)
+    return 0;
+  if (GET_CODE (XEXP (exp, 0)) != EQ_ATTR)
+    return 0;
+
+  rtx next = exp;
+  int ior_depth = 0;
+  int is_first = 1;
+
+  const char *attr_name_cmp = XSTR (XEXP (exp, 0), 0);
+
+  while (1)
+    {
+      rtx op1 = XEXP (next, 0);
+      rtx op2 = XEXP (next, 1);
+
+      if (GET_CODE (op1) != EQ_ATTR)
+	return 0;
+
+      const char *attr_name = XSTR (op1, 0);
+      const char *cmp_val = XSTR (op1, 1);
+
+      /* pointer compare is enough.  */
+      if (attr_name_cmp != attr_name)
+	return 0;
+
+      if (write_cases)
+	{
+	  struct attr_desc *attr = find_attr (&attr_name, 0);
+	  gcc_assert (attr);
+	  if (is_first)
+	    {
+	      fprintf (outf, "(");
+	      is_first = 0;
+	      int i;
+	      for (i = 0; i < cached_attr_count; i++)
+		if (attr->name == cached_attrs[i])
+		  break;
+
+	      if (i < cached_attr_count && (attrs_cached & (1U << i)) != 0)
+		fprintf (outf, "cached_%s", attr->name);
+	      else if (i < cached_attr_count &&
+		       (attrs_to_cache & (1U << i)) != 0)
+		fprintf (outf, "(cached_%s = get_attr_%s (insn))", attr->name,
+			 attr->name);
+	      else
+		fprintf (outf, "get_attr_%s (insn)", attr->name);
+	      fprintf (outf, ")\n");
+	      write_indent (outf, indent);
+	      fprintf (outf, "{\n");
+	    }
+	  write_indent (outf, indent);
+	  fprintf (outf, "case ");
+	  write_attr_valueq (outf, attr, cmp_val);
+	  fprintf (outf, ":\n");
+	}
+
+      const int code = GET_CODE (op2);
+      if (code != IOR)
+	{
+	  if (code == EQ_ATTR)
+	    {
+	      const char *attr_name = XSTR (op2, 0);
+	      const char *cmp_val = XSTR (op2, 1);
+
+	      if (attr_name == alternative_name)
+		return 0;
+
+	      struct attr_desc *attr = find_attr (&attr_name, 0);
+	      gcc_assert (attr);
+
+	      if (attr->is_const)
+		return 0;
+	      else if (write_cases)
+		{
+		  write_indent (outf, indent);
+		  fprintf (outf, "case ");
+		  write_attr_valueq (outf, attr, cmp_val);
+		  fprintf (outf, ":\n");
+		}
+	    }
+	  break;
+	}
+      next = op2;
+      ior_depth++;
+    }
+  return ior_depth > 2;
+}
+
 /* Write out a series of tests and assignment statements to perform tests and
    sets of an attribute value.  We are passed an indentation amount and prefix
    and suffix strings to write around each attribute value (e.g., "return"
@@ -4123,6 +4220,7 @@  write_attr_set (FILE *outf, struct attr_desc *attr, int indent, rtx value,
 		const char *prefix, const char *suffix, rtx known_true,
 		int insn_code, int insn_index, unsigned int attrs_cached)
 {
+  int n_switches = 0;
   if (GET_CODE (value) == COND)
     {
       /* Assume the default value will be the default of the COND unless we
@@ -4132,6 +4230,7 @@  write_attr_set (FILE *outf, struct attr_desc *attr, int indent, rtx value,
       rtx newexp;
       int first_if = 1;
       int i;
+      int is_switch = 0;
 
       if (cached_attr_count)
 	{
@@ -4176,40 +4275,68 @@  write_attr_set (FILE *outf, struct attr_desc *attr, int indent, rtx value,
 	  if (inner_true == false_rtx)
 	    continue;
 
+	  is_switch = check_attr_set_switch (outf, testexp, attrs_cached, 0,
+					     indent);
+
 	  attrs_cached_inside = attrs_cached;
 	  attrs_cached_after = attrs_cached;
 	  write_indent (outf, indent);
-	  fprintf (outf, "%sif ", first_if ? "" : "else ");
-	  first_if = 0;
-	  write_test_expr (outf, testexp, attrs_cached,
-			   (FLG_AFTER | FLG_INSIDE | FLG_OUTSIDE_AND));
-	  attrs_cached = attrs_cached_after;
-	  fprintf (outf, "\n");
-	  write_indent (outf, indent + 2);
-	  fprintf (outf, "{\n");
+	  if (is_switch)
+	    {
+	      fprintf (outf, "switch ");
+	      n_switches++;
+	      first_if = 1;
+	      check_attr_set_switch (outf, testexp, attrs_cached, 1, indent);
+	      indent += 4;
+	    }
+	  else
+	    {
+	      fprintf (outf, "%sif ", first_if ? "" : "else ");
+	      first_if = 0;
+	      write_test_expr (outf, testexp, attrs_cached,
+			       (FLG_AFTER | FLG_INSIDE | FLG_OUTSIDE_AND));
+	      attrs_cached = attrs_cached_after;
+	      fprintf (outf, "\n");
+	    }
+	  if (!is_switch)
+	    {
+	      write_indent (outf, indent + 2);
+	      fprintf (outf, "{\n");
+	    }
+
 
 	  write_attr_set (outf, attr, indent + 4,
 			  XVECEXP (value, 0, i + 1), prefix, suffix,
 			  inner_true, insn_code, insn_index,
 			  attrs_cached_inside);
 	  write_indent (outf, indent + 2);
-	  fprintf (outf, "}\n");
+	  if (is_switch)
+	    {
+	      fprintf (outf, "break;\n");
+	      write_indent (outf, indent);
+	      fprintf (outf, "default:\n");
+	      indent += 4;
+	    }
+	  else
+	    fprintf (outf, "}\n");
 	  our_known_true = newexp;
 	}
 
-      if (! first_if)
+      if (! first_if && ! is_switch)
 	{
 	  write_indent (outf, indent);
 	  fprintf (outf, "else\n");
 	  write_indent (outf, indent + 2);
 	  fprintf (outf, "{\n");
 	}
+      else if (is_switch)
+	write_indent (outf, indent);
 
-      write_attr_set (outf, attr, first_if ? indent : indent + 4, default_val,
+      write_attr_set (outf, attr, (first_if || is_switch) ? indent : indent + 4, default_val,
 		      prefix, suffix, our_known_true, insn_code, insn_index,
 		      attrs_cached);
 
-      if (! first_if)
+      if (! first_if && ! is_switch)
 	{
 	  write_indent (outf, indent + 2);
 	  fprintf (outf, "}\n");
@@ -4222,6 +4349,12 @@  write_attr_set (FILE *outf, struct attr_desc *attr, int indent, rtx value,
       write_attr_value (outf, attr, value);
       fprintf (outf, "%s\n", suffix);
     }
+  while (n_switches--)
+    {
+      indent -= 2;
+      write_indent (outf, indent);
+      fprintf (outf, "}\n");
+    }
 }
 
 /* Write a series of case statements for every instruction in list IE.