[CodeGenPrepare] Don't split the store if it is volatile

We shouldn't split the store when it is volatile.

Differential Revision: https://reviews.llvm.org/D61169

llvm-svn: 360228

1 files changed, 17 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/PowerPC/splitstore-check-volatile.ll b/llvm/test/CodeGen/PowerPC/splitstore-check-volatile.ll
new file mode 100644
index 00000000000..e40817d2e32
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/splitstore-check-volatile.ll
@@ -0,0 +1,17 @@
+; Test that CodeGenPrepare respect the volatile flag when splitting a store.
+;
+; RUN: opt -S -codegenprepare -force-split-store < %s  | FileCheck %s
+
+define void @fun(i16* %Src, i16* %Dst) {
+; CHECK: store volatile i16 %8, i16* %Dst 
+  %1 = load i16, i16* %Src
+  %2 = trunc i16 %1 to i8
+  %3 = lshr i16 %1, 8
+  %4 = trunc i16 %3 to i8
+  %5 = zext i8 %2 to i16
+  %6 = zext i8 %4 to i16
+  %7 = shl nuw i16 %6, 8
+  %8 = or i16 %7, %5
+  store volatile i16 %8, i16* %Dst
+  ret void
+}