[patch,avr] Add built-in function to emit NOPs

[patch,avr] Add built-in function to emit NOPs

[Georg-Johann Lay]

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This adds a new built-in function that inserts a requested number of NOPs into 
the instruction stream.  I found it useful when testing avr-gcc.

Ok to apply?


Johann


	* doc/extend.texi (AVR Built-in Functions): Document
	__builtin_avr_nops.
	* config/avr/builtins.def (NOPS): New.
	* config/avr/avr.c (avr_expand_nops): New static function.
	(avr_expand_builtin): Use it to handle AVR_BUILTIN_NOPS.

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Index: doc/extend.texi
===================================================================
--- doc/extend.texi	(revision 238849)
+++ doc/extend.texi	(working copy)
@@ -12552,6 +12552,14 @@ __builtin_avr_insert_bits (0xffff3210, b
 __builtin_avr_insert_bits (0x01234567, bits, 0)
 @end smallexample
 
+@smallexample
+void __builtin_avr_nops (unsigned count)
+@end smallexample
+
+@noindent
+Insert @code{count} @code{NOP} instructions.
+The number of instructions must be a compile-time integer constant.
+
 @node Blackfin Built-in Functions
 @subsection Blackfin Built-in Functions
 
Index: config/avr/builtins.def
===================================================================
--- config/avr/builtins.def	(revision 238849)
+++ config/avr/builtins.def	(working copy)
@@ -51,6 +51,7 @@ DEF_BUILTIN (FMULSU, 2, int_ftype_char_u
 /* More complex stuff that cannot be mapped 1:1 to an instruction.  */
 
 DEF_BUILTIN (DELAY_CYCLES, -1, void_ftype_ulong, nothing, NULL)
+DEF_BUILTIN (NOPS,         -1, void_ftype_ulong, nothing, NULL)
 DEF_BUILTIN (INSERT_BITS, 3, uchar_ftype_ulong_uchar_uchar, insert_bits, NULL)
 DEF_BUILTIN (FLASH_SEGMENT, 1, char_ftype_const_memx_ptr, flash_segment, NULL)
 
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c	(revision 238879)
+++ config/avr/avr.c	(working copy)
@@ -12714,6 +12714,18 @@ avr_expand_delay_cycles (rtx operands0)
 }
 
 
+static void
+avr_expand_nops (rtx operands0)
+{
+  unsigned HOST_WIDE_INT n_nops = UINTVAL (operands0) & GET_MODE_MASK (HImode);
+
+  while (n_nops--)
+    {
+      emit_insn (gen_nopv (const1_rtx));
+    }
+}
+
+
 /* Compute the image of x under f, i.e. perform   x --> f(x)    */
 
 static int
@@ -13387,6 +13399,19 @@ avr_expand_builtin (tree exp, rtx target
 
         return NULL_RTX;
       }
+
+    case AVR_BUILTIN_NOPS:
+      {
+        arg0 = CALL_EXPR_ARG (exp, 0);
+        op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);
+
+        if (!CONST_INT_P (op0))
+          error ("%s expects a compile time integer constant", bname);
+        else
+          avr_expand_nops (op0);
+
+        return NULL_RTX;
+      }
 
     case AVR_BUILTIN_INSERT_BITS:
       {

Re: [patch,avr] Add built-in function to emit NOPs

[Denis Chertykov]

2016-08-01 11:23 GMT+03:00 Georg-Johann Lay <avr@gjlay.de>:
> This adds a new built-in function that inserts a requested number of NOPs
> into the instruction stream.  I found it useful when testing avr-gcc.
>
> Ok to apply?
>
>
> Johann
>
>
>         * doc/extend.texi (AVR Built-in Functions): Document
>         __builtin_avr_nops.
>         * config/avr/builtins.def (NOPS): New.
>         * config/avr/avr.c (avr_expand_nops): New static function.
>         (avr_expand_builtin): Use it to handle AVR_BUILTIN_NOPS.

Please apply.