Add support for acquire, release, and acq_rel memory ordering in PNaCl

test/Transforms/NaCl/atomic/atomic_others.ll

 ; RUN: opt -nacl-rewrite-atomics -S < %s | FileCheck %s
 ;
-; Validate that atomic non-sequentially consistent loads/stores get rewritten
-; into NaCl atomic builtins with sequentially consistent memory ordering (enum
-; value 6). This will change once we support other memory orderings.
+; Validate that atomic non-{acquire/release/acq_rel/seq_cst} loads/stores get
+; rewritten into NaCl atomic builtins with sequentially consistent memory
+; ordering (enum value 6), and that acquire/release/acq_rel remain as-is (enum
+; values 3/4/5).
 ;
 ; Note that monotonic doesn't exist in C11/C++11, and consume isn't implemented
 ; in LLVM yet.
 
 target datalayout = "p:32:32:32"
 
 ; CHECK-LABEL: @test_atomic_load_monotonic_i32
 define i32 @test_atomic_load_monotonic_i32(i32* %ptr) {
   ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.load.i32(i32* %ptr, i32 6)
   %res = load atomic i32* %ptr monotonic, align 4
@@ skipping 16 matching lines @@
 
 ; CHECK-LABEL: @test_atomic_store_unordered_i32
 define void @test_atomic_store_unordered_i32(i32* %ptr, i32 %value) {
   ; CHECK-NEXT: call void @llvm.nacl.atomic.store.i32(i32 %value, i32* %ptr, i32 6)
   store atomic i32 %value, i32* %ptr unordered, align 4
   ret void  ; CHECK-NEXT: ret void
 }
 
 ; CHECK-LABEL: @test_atomic_load_acquire_i32
 define i32 @test_atomic_load_acquire_i32(i32* %ptr) {
-  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.load.i32(i32* %ptr, i32 6)
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.load.i32(i32* %ptr, i32 3)
   %res = load atomic i32* %ptr acquire, align 4
   ret i32 %res  ; CHECK-NEXT: ret i32 %res
 }
 
 ; CHECK-LABEL: @test_atomic_store_release_i32
 define void @test_atomic_store_release_i32(i32* %ptr, i32 %value) {
-  ; CHECK-NEXT: call void @llvm.nacl.atomic.store.i32(i32 %value, i32* %ptr, i32 6)
+  ; CHECK-NEXT: call void @llvm.nacl.atomic.store.i32(i32 %value, i32* %ptr, i32 4)
   store atomic i32 %value, i32* %ptr release, align 4
   ret void  ; CHECK-NEXT: ret void
 }
 
-; CHECK: @test_fetch_and_add_i32
+; CHECK-LABEL: @test_fetch_and_add_i32
 define i32 @test_fetch_and_add_i32(i32* %ptr, i32 %value) {
-  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.rmw.i32(i32 1, i32* %ptr, i32 %value, i32 6)
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.rmw.i32(i32 1, i32* %ptr, i32 %value, i32 5)
   %res = atomicrmw add i32* %ptr, i32 %value acq_rel
   ret i32 %res  ; CHECK-NEXT: ret i32 %res
 }
+
+; Test all the valid cmpxchg orderings for success and failure.
+
+; CHECK-LABEL: @test_cmpxchg_seqcst_seqcst
+define { i32, i1 } @test_cmpxchg_seqcst_seqcst(i32* %ptr, i32 %value) {
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 6)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value seq_cst seq_cst
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_seqcst_acquire
+define { i32, i1 } @test_cmpxchg_seqcst_acquire(i32* %ptr, i32 %value) {
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 3)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value seq_cst acquire
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_seqcst_relaxed
+define { i32, i1 } @test_cmpxchg_seqcst_relaxed(i32* %ptr, i32 %value) {
+  ; Failure ordering is upgraded.
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 6)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value seq_cst monotonic
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_acqrel_acquire
+define { i32, i1 } @test_cmpxchg_acqrel_acquire(i32* %ptr, i32 %value) {
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 5, i32 3)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value acq_rel acquire
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_acqrel_relaxed
+define { i32, i1 } @test_cmpxchg_acqrel_relaxed(i32* %ptr, i32 %value) {
+  ; Success and failure ordering are upgraded.
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 6)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value acq_rel monotonic
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_release_relaxed
+define { i32, i1 } @test_cmpxchg_release_relaxed(i32* %ptr, i32 %value) {
+  ; Success and failure ordering are upgraded.
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 6)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value release monotonic
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_acquire_acquire
+define { i32, i1 } @test_cmpxchg_acquire_acquire(i32* %ptr, i32 %value) {
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 3, i32 3)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value acquire acquire
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_acquire_relaxed
+define { i32, i1 } @test_cmpxchg_acquire_relaxed(i32* %ptr, i32 %value) {
+  ; Failure ordering is upgraded.
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 3, i32 3)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value acquire monotonic
+  ret { i32, i1 } %res
+}
+
+; CHECK-LABEL: @test_cmpxchg_relaxed_relaxed
+define { i32, i1 } @test_cmpxchg_relaxed_relaxed(i32* %ptr, i32 %value) {
+  ; Failure ordering is upgraded.
+  ; CHECK-NEXT: %res = call i32 @llvm.nacl.atomic.cmpxchg.i32(i32* %ptr, i32 0, i32 %value, i32 6, i32 6)
+  %res = cmpxchg i32* %ptr, i32 0, i32 %value monotonic monotonic
+  ret { i32, i1 } %res
+}