[Patch, AVR]: QI builtins for parity, popcount, 1<< n

[Georg-Johann Lay <avr at gjlay dot de>]

The recent implementation of some asm function in libgcc added
__popcountqi2 and __parityqi2. This patch makes these functions
available as __builtin_avr_popcount8 resp. __builtin_avr_parity8.

Moreover, just out of a mood, I wrote a builtin for 1<<n.
1<<n is sometimes used to set a variable SFR bit. The builtin supplies
a fast, loop-free implementation.

The nice thing is that all these can represented explicitly so that
gcc sees what's going on and can fold if it sees operation on a
compile time constant.

Johann

	* config/avr/avr.c (avr_init_builtins, avr_builtin_id,
	bdesc_1arg): Add support for __builtin_avr_parity8,
	__builtin_avr_popcount8, __builtin_avr_pow2.
	(adjust_insn_length): Filter out "ashlqi2_1" insn in length
	computation.
	* config/avr/avr.c (avr_cpu_cpp_builtins): New builtin defines for
	__BUILTIN_AVR_PARITY8, __BUILTIN_AVR_POPCOUNT8,	__BUILTIN_AVR_POW2.
	* config/avr/avr.md (parityqi2): New expander.
	(popcountqi2): New expander.
	(*parityqihi2.libgcc): New insn.
	(*popcountqi2.libgcc): New insn.
	(ashlqi2_1): New insn.
	* doc/extend.texi (AVR Built-in Functions): Document new builtins
	__builtin_avr_parity8, __builtin_avr_popcount8,
	__builtin_avr_pow2.

Index: doc/extend.texi
===================================================================
--- doc/extend.texi	(Revision 175104)
+++ doc/extend.texi	(Arbeitskopie)
@@ -8203,6 +8203,21 @@ int __builtin_avr_fmuls (char, char)
 int __builtin_avr_fmulsu (char, unsigned char)
 @end smallexample
 
+The following built-in functions are a supplements to gcc's
+@code{__builtin_parity*} resp. @code{__builtin_popcount*} built-ins
+for 8-bit values and are implemented as library calls:
+@smallexample
+unsigned char __builtin_avr_parity8 (unsigned char)
+unsigned char __builtin_avr_popcount8 (unsigned char)
+@end smallexample
+
+@smallexample
+unsigned char __builtin_avr_pow2 (unsigned char)
+@end smallexample
+This built-in supplies a fast, loop-free implementation for the @var{N}-th
+power of two as of @code{1 << (N & 7)} that takes about seven ticks resp.
+seven instructions.
+
 In order to delay execution for a specific number of cycles, GCC
 implements
 @smallexample
Index: config/avr/avr.md
===================================================================
--- config/avr/avr.md	(Revision 175104)
+++ config/avr/avr.md	(Arbeitskopie)
@@ -3321,6 +3321,62 @@ (define_insn "delay_cycles_4"
   [(set_attr "length" "9")
    (set_attr "cc" "clobber")])
 
+;; __builtin_avr_parity8
+(define_expand "parityqi2"
+  [(set (reg:QI 24)
+        (match_operand:QI 1 "register_operand" ""))
+   (set (reg:HI 24)
+        (zero_extend:HI (parity:QI (reg:QI 24))))
+   (set (match_operand:QI 0 "register_operand" "")
+        (reg:QI 24))]
+  ""
+  "")
+
+(define_insn "*parityqihi2.libgcc"
+  [(set (reg:HI 24)
+        (zero_extend:HI (parity:QI (reg:QI 24))))]
+  ""
+  "%~call __parityqi2"
+  [(set_attr "type" "xcall")
+   (set_attr "cc" "clobber")])
+
+;; __builtin_avr_popcount8
+(define_expand "popcountqi2"
+  [(set (reg:QI 24)
+        (match_operand:QI 1 "register_operand" ""))
+   (set (reg:QI 24)
+        (popcount:QI (reg:QI 24)))
+   (set (match_operand:QI 0 "register_operand" "")
+        (reg:QI 24))]
+  ""
+  "")
+
+(define_insn "*popcountqi2.libgcc"
+  [(set (reg:QI 24)
+        (popcount:QI (reg:QI 24)))]
+  ""
+  "%~call __popcountqi2"
+  [(set_attr "type" "xcall")
+   (set_attr "cc" "clobber")])
+
+;; __builtin_avr_pow2
+;; $0 = (1 << ($1 & 7))
+(define_insn "ashlqi2_1"
+  [(set (match_operand:QI 0 "register_operand" "=&d")
+        (ashift:QI (const_int 1)
+                   (and:QI (match_operand:QI 1 "register_operand" "r")
+                           (const_int 7))))]
+  ""
+  "ldi %0, 1
+	sbrc %1, 1
+	ldi %0, 4
+	sbrc %1, 0
+	lsl %0
+	sbrc %1, 2
+	swap %0"
+  [(set_attr "length" "7")
+   (set_attr "cc" "clobber")])
+
 ;; CPU instructions
 
 ;; NOP taking 1 or 2 Ticks 
Index: config/avr/avr-c.c
===================================================================
--- config/avr/avr-c.c	(Revision 175104)
+++ config/avr/avr-c.c	(Arbeitskopie)
@@ -93,6 +93,9 @@ avr_cpu_cpp_builtins (struct cpp_reader
   cpp_define (pfile, "__BUILTIN_AVR_SLEEP");
   cpp_define (pfile, "__BUILTIN_AVR_SWAP");
   cpp_define (pfile, "__BUILTIN_AVR_DELAY_CYCLES");
+  cpp_define (pfile, "__BUILTIN_AVR_PARITY8");
+  cpp_define (pfile, "__BUILTIN_AVR_POPCOUNT8");
+  cpp_define (pfile, "__BUILTIN_AVR_POW2");
 
   if (AVR_HAVE_MUL)
     {
Index: config/avr/avr.c
===================================================================
--- config/avr/avr.c	(Revision 175104)
+++ config/avr/avr.c	(Arbeitskopie)
@@ -4740,9 +4740,11 @@ adjust_insn_length (rtx insn, int len)
 	      break;
 	    }
 	}
-      else if (GET_CODE (op[1]) == ASHIFT
-	  || GET_CODE (op[1]) == ASHIFTRT
-	  || GET_CODE (op[1]) == LSHIFTRT)
+      else if ((GET_CODE (op[1]) == ASHIFT
+                || GET_CODE (op[1]) == ASHIFTRT
+                || GET_CODE (op[1]) == LSHIFTRT)
+               /* Filter out "ashlqi2_1" */
+               && AND != GET_CODE (XEXP (op[1], 1)))
 	{
 	  rtx ops[10];
 	  ops[0] = op[0];
@@ -6614,7 +6616,10 @@ enum avr_builtin_id
     AVR_BUILTIN_FMUL,
     AVR_BUILTIN_FMULS,
     AVR_BUILTIN_FMULSU,
-    AVR_BUILTIN_DELAY_CYCLES
+    AVR_BUILTIN_DELAY_CYCLES,
+    AVR_BUILTIN_PARITY8,
+    AVR_BUILTIN_POPCOUNT8,
+    AVR_BUILTIN_POW2
   };
 
 #define DEF_BUILTIN(NAME, TYPE, CODE)                                   \
@@ -6665,6 +6670,12 @@ avr_init_builtins (void)
   DEF_BUILTIN ("__builtin_avr_swap", uchar_ftype_uchar, AVR_BUILTIN_SWAP);
   DEF_BUILTIN ("__builtin_avr_delay_cycles", void_ftype_ulong, 
                AVR_BUILTIN_DELAY_CYCLES);
+  DEF_BUILTIN ("__builtin_avr_parity8", uchar_ftype_uchar,
+               AVR_BUILTIN_PARITY8);
+  DEF_BUILTIN ("__builtin_avr_popcount8", uchar_ftype_uchar,
+               AVR_BUILTIN_POPCOUNT8);
+  DEF_BUILTIN ("__builtin_avr_pow2", uchar_ftype_uchar,
+               AVR_BUILTIN_POW2);
 
   if (AVR_HAVE_MUL)
     {
@@ -6694,6 +6705,9 @@ static const struct avr_builtin_descript
 bdesc_1arg[] =
   {
     { CODE_FOR_rotlqi3_4, "__builtin_avr_swap", AVR_BUILTIN_SWAP }
+    , { CODE_FOR_parityqi2, "__builtin_avr_parity8", AVR_BUILTIN_PARITY8 }
+    , { CODE_FOR_popcountqi2, "__builtin_avr_popcount8", AVR_BUILTIN_POPCOUNT8 }
+    , { CODE_FOR_ashlqi2_1, "__builtin_avr_pow2", AVR_BUILTIN_POW2 }
   };
 
 static const struct avr_builtin_description