[Hexagon] Do not optimize volatile stack spill slots

llvm-svn: 276916

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Hexagon/opt-spill-volatile.ll b/llvm/test/CodeGen/Hexagon/opt-spill-volatile.ll
new file mode 100644
index 00000000000..99dd4646d74
--- /dev/null
+++ b/llvm/test/CodeGen/Hexagon/opt-spill-volatile.ll
@@ -0,0 +1,29 @@
+; RUN: llc -march=hexagon < %s | FileCheck %s
+; Check that the load/store to the volatile stack object has not been
+; optimized away.
+
+target triple = "hexagon"
+
+; CHECK-LABEL: foo
+; CHECK: memw(r29+#4) =
+; CHECK: = memw(r29 + #4)
+define i32 @foo(i32 %a) #0 {
+entry:
+  %x = alloca i32, align 4
+  %x.0.x.0..sroa_cast = bitcast i32* %x to i8*
+  call void @llvm.lifetime.start(i64 4, i8* %x.0.x.0..sroa_cast)
+  store volatile i32 0, i32* %x, align 4
+  %call = tail call i32 bitcast (i32 (...)* @bar to i32 ()*)() #0
+  %x.0.x.0. = load volatile i32, i32* %x, align 4
+  %add = add nsw i32 %x.0.x.0., %a
+  call void @llvm.lifetime.end(i64 4, i8* %x.0.x.0..sroa_cast)
+  ret i32 %add
+}
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+declare i32 @bar(...) #0
+
+attributes #0 = { nounwind }
+attributes #1 = { argmemonly nounwind }