xtensa: Make use of DEPBITS instruction

This patch implements bitfield insertion MD pattern using the DEPBITS
machine instruction, the counterpart of the EXTUI instruction, if
available.

     /* example */
     struct foo {
       unsigned int b:10;
       unsigned int r:11;
       unsigned int g:11;
     };
     void test(struct foo *p) {
       p->g >>= 1;
     }

     ;; result (endianness: little)
     test:
     	entry	sp, 32
     	l32i.n	a8, a2, 0
     	extui	a9, a8, 1, 10
     	depbits	a8, a9, 0, 11
     	s32i.n	a8, a2, 0
     	retw.n

gcc/ChangeLog:

	* config/xtensa/xtensa.h (TARGET_DEPBITS): New macro.
	* config/xtensa/xtensa.md (insvsi): New insn pattern.

diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
index 9009db0109779dfebeaa2ae88ffde02a2a5e436f..a8a0565c81e73eae0f332a2e31e9a30b985b71ed 100644 (file)
--- a/gcc/config/xtensa/xtensa.h
+++ b/gcc/config/xtensa/xtensa.h
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.  If not see
 #define TARGET_MINMAX          XCHAL_HAVE_MINMAX
 #define TARGET_SEXT            XCHAL_HAVE_SEXT
 #define TARGET_CLAMPS          XCHAL_HAVE_CLAMPS
+#define TARGET_DEPBITS         XCHAL_HAVE_DEPBITS
 #define TARGET_BOOLEANS                XCHAL_HAVE_BOOLEANS
 #define TARGET_HARD_FLOAT      XCHAL_HAVE_FP
 #define TARGET_HARD_FLOAT_DIV  XCHAL_HAVE_FP_DIV

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 4c4270ae8bcb700850a791c0b1e7295d9bccd439..029be99e3b4efae4c0fec82dcd669bf67bae9c21 100644 (file)
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -1014,7 +1014,7 @@
    (set_attr "length"  "3")])
 
 \f
-;; Field extract instructions.
+;; Field extract and insert instructions.
 
 (define_expand "extvsi"
   [(set (match_operand:SI 0 "register_operand" "")
@@ -1148,6 +1148,25 @@
    (set_attr "mode"    "SI")
    (set_attr "length"  "6")])
 
+(define_insn "insvsi"
+  [(set (zero_extract:SI (match_operand:SI 0 "register_operand" "+a")
+                        (match_operand:SI 1 "extui_fldsz_operand" "i")
+                        (match_operand:SI 2 "const_int_operand" "i"))
+       (match_operand:SI 3 "register_operand" "r"))]
+  "TARGET_DEPBITS"
+{
+  int shift;
+  if (BITS_BIG_ENDIAN)
+    shift = (32 - (INTVAL (operands[1]) + INTVAL (operands[2]))) & 0x1f;
+  else
+    shift = INTVAL (operands[2]) & 0x1f;
+  operands[2] = GEN_INT (shift);
+  return "depbits\t%0, %3, %2, %1";
+}
+  [(set_attr "type"    "arith")
+   (set_attr "mode"    "SI")
+   (set_attr "length"  "3")])
+
 \f
 ;; Conversions.