--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/config/riscv/sync.md	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,194 @@
+;; Machine description for RISC-V atomic operations.
+;; Copyright (C) 2011-2017 Free Software Foundation, Inc.
+;; Contributed by Andrew Waterman (andrew@sifive.com).
+;; Based on MIPS target for GNU compiler.
+
+;; This file is part of GCC.
+
+;; GCC is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; GCC is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GCC; see the file COPYING3.  If not see
+;; <http://www.gnu.org/licenses/>.
+
+(define_c_enum "unspec" [
+  UNSPEC_COMPARE_AND_SWAP
+  UNSPEC_SYNC_OLD_OP
+  UNSPEC_SYNC_EXCHANGE
+  UNSPEC_ATOMIC_STORE
+  UNSPEC_MEMORY_BARRIER
+])
+
+(define_code_iterator any_atomic [plus ior xor and])
+(define_code_attr atomic_optab
+  [(plus "add") (ior "or") (xor "xor") (and "and")])
+
+;; Memory barriers.
+
+(define_expand "mem_thread_fence"
+  [(match_operand:SI 0 "const_int_operand" "")] ;; model
+  ""
+{
+  if (INTVAL (operands[0]) != MEMMODEL_RELAXED)
+    {
+      rtx mem = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
+      MEM_VOLATILE_P (mem) = 1;
+      emit_insn (gen_mem_thread_fence_1 (mem, operands[0]));
+    }
+  DONE;
+})
+
+;; Until the RISC-V memory model (hence its mapping from C++) is finalized,
+;; conservatively emit a full FENCE.
+(define_insn "mem_thread_fence_1"
+  [(set (match_operand:BLK 0 "" "")
+	(unspec:BLK [(match_dup 0)] UNSPEC_MEMORY_BARRIER))
+   (match_operand:SI 1 "const_int_operand" "")] ;; model
+  ""
+  "fence\tiorw,iorw")
+
+;; Atomic memory operations.
+
+;; Implement atomic stores with amoswap.  Fall back to fences for atomic loads.
+(define_insn "atomic_store<mode>"
+  [(set (match_operand:GPR 0 "memory_operand" "=A")
+    (unspec_volatile:GPR
+      [(match_operand:GPR 1 "reg_or_0_operand" "rJ")
+       (match_operand:SI 2 "const_int_operand")]      ;; model
+      UNSPEC_ATOMIC_STORE))]
+  "TARGET_ATOMIC"
+  "%F2amoswap.<amo>%A2 zero,%z1,%0"
+  [(set (attr "length") (const_int 8))])
+
+(define_insn "atomic_<atomic_optab><mode>"
+  [(set (match_operand:GPR 0 "memory_operand" "+A")
+	(unspec_volatile:GPR
+	  [(any_atomic:GPR (match_dup 0)
+		     (match_operand:GPR 1 "reg_or_0_operand" "rJ"))
+	   (match_operand:SI 2 "const_int_operand")] ;; model
+	 UNSPEC_SYNC_OLD_OP))]
+  "TARGET_ATOMIC"
+  "%F2amo<insn>.<amo>%A2 zero,%z1,%0"
+  [(set (attr "length") (const_int 8))])
+
+(define_insn "atomic_fetch_<atomic_optab><mode>"
+  [(set (match_operand:GPR 0 "register_operand" "=&r")
+	(match_operand:GPR 1 "memory_operand" "+A"))
+   (set (match_dup 1)
+	(unspec_volatile:GPR
+	  [(any_atomic:GPR (match_dup 1)
+		     (match_operand:GPR 2 "reg_or_0_operand" "rJ"))
+	   (match_operand:SI 3 "const_int_operand")] ;; model
+	 UNSPEC_SYNC_OLD_OP))]
+  "TARGET_ATOMIC"
+  "%F3amo<insn>.<amo>%A3 %0,%z2,%1"
+  [(set (attr "length") (const_int 8))])
+
+(define_insn "atomic_exchange<mode>"
+  [(set (match_operand:GPR 0 "register_operand" "=&r")
+	(unspec_volatile:GPR
+	  [(match_operand:GPR 1 "memory_operand" "+A")
+	   (match_operand:SI 3 "const_int_operand")] ;; model
+	  UNSPEC_SYNC_EXCHANGE))
+   (set (match_dup 1)
+	(match_operand:GPR 2 "register_operand" "0"))]
+  "TARGET_ATOMIC"
+  "%F3amoswap.<amo>%A3 %0,%z2,%1"
+  [(set (attr "length") (const_int 8))])
+
+(define_insn "atomic_cas_value_strong<mode>"
+  [(set (match_operand:GPR 0 "register_operand" "=&r")
+	(match_operand:GPR 1 "memory_operand" "+A"))
+   (set (match_dup 1)
+	(unspec_volatile:GPR [(match_operand:GPR 2 "reg_or_0_operand" "rJ")
+			      (match_operand:GPR 3 "reg_or_0_operand" "rJ")
+			      (match_operand:SI 4 "const_int_operand")  ;; mod_s
+			      (match_operand:SI 5 "const_int_operand")] ;; mod_f
+	 UNSPEC_COMPARE_AND_SWAP))
+   (clobber (match_scratch:GPR 6 "=&r"))]
+  "TARGET_ATOMIC"
+  "%F5 1: lr.<amo>%A5 %0,%1; bne %0,%z2,1f; sc.<amo>%A4 %6,%z3,%1; bnez %6,1b; 1:"
+  [(set (attr "length") (const_int 20))])
+
+(define_expand "atomic_compare_and_swap<mode>"
+  [(match_operand:SI 0 "register_operand" "")   ;; bool output
+   (match_operand:GPR 1 "register_operand" "")  ;; val output
+   (match_operand:GPR 2 "memory_operand" "")    ;; memory
+   (match_operand:GPR 3 "reg_or_0_operand" "")  ;; expected value
+   (match_operand:GPR 4 "reg_or_0_operand" "")  ;; desired value
+   (match_operand:SI 5 "const_int_operand" "")  ;; is_weak
+   (match_operand:SI 6 "const_int_operand" "")  ;; mod_s
+   (match_operand:SI 7 "const_int_operand" "")] ;; mod_f
+  "TARGET_ATOMIC"
+{
+  emit_insn (gen_atomic_cas_value_strong<mode> (operands[1], operands[2],
+						operands[3], operands[4],
+						operands[6], operands[7]));
+
+  rtx compare = operands[1];
+  if (operands[3] != const0_rtx)
+    {
+      rtx difference = gen_rtx_MINUS (<MODE>mode, operands[1], operands[3]);
+      compare = gen_reg_rtx (<MODE>mode);
+      emit_insn (gen_rtx_SET (compare, difference));
+    }
+
+  if (word_mode != <MODE>mode)
+    {
+      rtx reg = gen_reg_rtx (word_mode);
+      emit_insn (gen_rtx_SET (reg, gen_rtx_SIGN_EXTEND (word_mode, compare)));
+      compare = reg;
+    }
+
+  emit_insn (gen_rtx_SET (operands[0], gen_rtx_EQ (SImode, compare, const0_rtx)));
+  DONE;
+})
+
+(define_expand "atomic_test_and_set"
+  [(match_operand:QI 0 "register_operand" "")     ;; bool output
+   (match_operand:QI 1 "memory_operand" "+A")    ;; memory
+   (match_operand:SI 2 "const_int_operand" "")]   ;; model
+  "TARGET_ATOMIC"
+{
+  /* We have no QImode atomics, so use the address LSBs to form a mask,
+     then use an aligned SImode atomic. */
+  rtx result = operands[0];
+  rtx mem = operands[1];
+  rtx model = operands[2];
+  rtx addr = force_reg (Pmode, XEXP (mem, 0));
+
+  rtx aligned_addr = gen_reg_rtx (Pmode);
+  emit_move_insn (aligned_addr, gen_rtx_AND (Pmode, addr, GEN_INT (-4)));
+
+  rtx aligned_mem = change_address (mem, SImode, aligned_addr);
+  set_mem_alias_set (aligned_mem, 0);
+
+  rtx offset = gen_reg_rtx (SImode);
+  emit_move_insn (offset, gen_rtx_AND (SImode, gen_lowpart (SImode, addr),
+				       GEN_INT (3)));
+
+  rtx tmp = gen_reg_rtx (SImode);
+  emit_move_insn (tmp, GEN_INT (1));
+
+  rtx shmt = gen_reg_rtx (SImode);
+  emit_move_insn (shmt, gen_rtx_ASHIFT (SImode, offset, GEN_INT (3)));
+
+  rtx word = gen_reg_rtx (SImode);
+  emit_move_insn (word, gen_rtx_ASHIFT (SImode, tmp, shmt));
+
+  tmp = gen_reg_rtx (SImode);
+  emit_insn (gen_atomic_fetch_orsi (tmp, aligned_mem, word, model));
+
+  emit_move_insn (gen_lowpart (SImode, result),
+		  gen_rtx_LSHIFTRT (SImode, tmp,
+				    gen_lowpart (SImode, shmt)));
+  DONE;
+})