Weak relaxing of the constraints on atomics in MemoryDependencyAnalysis
Monotonic accesses do not have to kill the analysis, as long as the QueryInstr is not
itself atomic.
llvm-svn: 215942
diff --git a/llvm/test/Transforms/DeadStoreElimination/atomic.ll b/llvm/test/Transforms/DeadStoreElimination/atomic.ll
index 2e84298..621958d 100644
--- a/llvm/test/Transforms/DeadStoreElimination/atomic.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/atomic.ll
@@ -105,3 +105,50 @@
ret i32 %x
}
+; DSE across monotonic load (allowed as long as the eliminated store isUnordered)
+define i32 @test9() nounwind uwtable ssp {
+; CHECK: test9
+; CHECK-NOT: store i32 0
+; CHECK: store i32 1
+entry:
+ store i32 0, i32* @x
+ %x = load atomic i32* @y monotonic, align 4
+ store i32 1, i32* @x
+ ret i32 %x
+}
+
+; DSE across monotonic store (allowed as long as the eliminated store isUnordered)
+define void @test10() nounwind uwtable ssp {
+; CHECK: test10
+; CHECK-NOT: store i32 0
+; CHECK: store i32 1
+entry:
+ store i32 0, i32* @x
+ store atomic i32 42, i32* @y monotonic, align 4
+ store i32 1, i32* @x
+ ret void
+}
+
+; DSE across monotonic load (forbidden since the eliminated store is atomic)
+define i32 @test11() nounwind uwtable ssp {
+; CHECK: test11
+; CHECK: store atomic i32 0
+; CHECK: store atomic i32 1
+entry:
+ store atomic i32 0, i32* @x monotonic, align 4
+ %x = load atomic i32* @y monotonic, align 4
+ store atomic i32 1, i32* @x monotonic, align 4
+ ret i32 %x
+}
+
+; DSE across monotonic store (forbidden since the eliminated store is atomic)
+define void @test12() nounwind uwtable ssp {
+; CHECK: test12
+; CHECK: store atomic i32 0
+; CHECK: store atomic i32 1
+entry:
+ store atomic i32 0, i32* @x monotonic, align 4
+ store atomic i32 42, i32* @y monotonic, align 4
+ store atomic i32 1, i32* @x monotonic, align 4
+ ret void
+}