[WebAssembly] Add atomic.fence instruction
Summary:
This adds `atomic.fence` instruction:
https://github.com/WebAssembly/threads/blob/master/proposals/threads/Overview.md#fence-operator
And we now emit the new `atomic.fence` instruction for multithread
fences, rather than the prevous `atomic.rmw` hack.
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, jfb, tlively, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66794
llvm-svn: 370272
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
index e85aa57..fecb895 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
@@ -127,6 +127,19 @@
} // Predicates = [HasAtomics]
//===----------------------------------------------------------------------===//
+// Atomic fences
+//===----------------------------------------------------------------------===//
+
+// A compiler fence instruction that prevents reordering of instructions.
+let Defs = [ARGUMENTS] in {
+let isPseudo = 1, hasSideEffects = 1 in
+defm COMPILER_FENCE : ATOMIC_NRI<(outs), (ins), [], "compiler_fence">;
+let hasSideEffects = 1 in
+defm ATOMIC_FENCE : ATOMIC_NRI<(outs), (ins i8imm:$flags), [], "atomic.fence",
+ 0x03>;
+} // Defs = [ARGUMENTS]
+
+//===----------------------------------------------------------------------===//
// Atomic loads
//===----------------------------------------------------------------------===//
@@ -887,13 +900,3 @@
ATOMIC_RMW8_U_CMPXCHG_I32, ATOMIC_RMW16_U_CMPXCHG_I32,
ATOMIC_RMW8_U_CMPXCHG_I64, ATOMIC_RMW16_U_CMPXCHG_I64,
ATOMIC_RMW32_U_CMPXCHG_I64>;
-
-//===----------------------------------------------------------------------===//
-// Atomic fences
-//===----------------------------------------------------------------------===//
-
-// A compiler fence instruction that prevents reordering of instructions.
-let Defs = [ARGUMENTS] in {
-let isPseudo = 1, hasSideEffects = 1 in
-defm COMPILER_FENCE : ATOMIC_NRI<(outs), (ins), [], "compiler_fence">;
-} // Defs = [ARGUMENTS]