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llvm-mirror/test/CodeGen/WebAssembly/atomic-fence.ll
Heejin Ahn afd7ae9283 [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
2019-08-28 23:13:43 +00:00

41 lines
1.3 KiB
LLVM

; RUN: llc < %s | FileCheck %s --check-prefix NOATOMIC
; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics | FileCheck %s
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
; A multithread fence is lowered to an atomic.fence instruction.
; CHECK-LABEL: multithread_fence:
; CHECK: atomic.fence
; NOATOMIC-NOT: i32.atomic.rmw.or
define void @multithread_fence() {
fence seq_cst
ret void
}
; Fences with weaker memory orderings than seq_cst should be treated the same
; because atomic memory access in wasm are sequentially consistent.
; CHECK-LABEL: multithread_weak_fence:
; CHECK: atomic.fence
; CHECK-NEXT: atomic.fence
; CHECK-NEXT: atomic.fence
define void @multithread_weak_fence() {
fence acquire
fence release
fence acq_rel
ret void
}
; A singlethread fence becomes compiler_fence instruction, a pseudo instruction
; that acts as a compiler barrier. The barrier should not be emitted to .s file.
; CHECK-LABEL: singlethread_fence:
; CHECK-NOT: compiler_fence
; CHECK-NOT: atomic_fence
define void @singlethread_fence() {
fence syncscope("singlethread") seq_cst
fence syncscope("singlethread") acquire
fence syncscope("singlethread") release
fence syncscope("singlethread") acq_rel
ret void
}