1 files changed, 55 insertions, 0 deletions
diff --git a/test/CodeGen/SystemZ/atomicrmw-xchg-02.ll b/test/CodeGen/SystemZ/atomicrmw-xchg-02.ll
new file mode 100644
index 0000000000000..31f802625a320
--- /dev/null
+++ b/test/CodeGen/SystemZ/atomicrmw-xchg-02.ll
@@ -0,0 +1,55 @@
+; Test 16-bit atomic exchange.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s -check-prefix=CHECK
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s -check-prefix=CHECK-SHIFT
+
+; Check exchange with a variable.
+; - CHECK is for the main loop.
+; - CHECK-SHIFT makes sure that the negated shift count used by the second
+;   RLL is set up correctly.  The negation is independent of the NILL and L
+;   tested in CHECK.  CHECK-SHIFT also checks that %r3 is not modified before
+;   being used in the RISBG (in contrast to things like atomic addition,
+;   which shift %r3 left so that %b is at the high end of the word).
+define i16 @f1(i16 *%src, i16 %b) {
+; CHECK: f1:
+; CHECK: sllg [[SHIFT:%r[1-9]+]], %r2, 3
+; CHECK: nill %r2, 65532
+; CHECK: l [[OLD:%r[0-9]+]], 0(%r2)
+; CHECK: [[LABEL:\.[^:]*]]:
+; CHECK: rll [[ROT:%r[0-9]+]], [[OLD]], 0([[SHIFT]])
+; CHECK: risbg [[ROT]], %r3, 32, 47, 16
+; CHECK: rll [[NEW:%r[0-9]+]], [[ROT]], 0({{%r[1-9]+}})
+; CHECK: cs [[OLD]], [[NEW]], 0(%r2)
+; CHECK: j{{g?}}lh [[LABEL]]
+; CHECK: rll %r2, [[OLD]], 16([[SHIFT]])
+; CHECK: br %r14
+;
+; CHECK-SHIFT: f1:
+; CHECK-SHIFT-NOT: %r3
+; CHECK-SHIFT: sllg [[SHIFT:%r[1-9]+]], %r2, 3
+; CHECK-SHIFT-NOT: %r3
+; CHECK-SHIFT: lcr [[NEGSHIFT:%r[1-9]+]], [[SHIFT]]
+; CHECK-SHIFT-NOT: %r3
+; CHECK-SHIFT: rll
+; CHECK-SHIFT-NOT: %r3
+; CHECK-SHIFT: risbg {{%r[0-9]+}}, %r3, 32, 47, 16
+; CHECK-SHIFT: rll {{%r[0-9]+}}, {{%r[0-9]+}}, 0([[NEGSHIFT]])
+; CHECK-SHIFT: rll
+; CHECK-SHIFT: br %r14
+  %res = atomicrmw xchg i16 *%src, i16 %b seq_cst
+  ret i16 %res
+}
+
+; Check exchange with a constant.  We should force the constant into
+; a register and use the sequence above.
+define i16 @f2(i16 *%src) {
+; CHECK: f2:
+; CHECK: lhi [[VALUE:%r[0-9]+]], -25536
+; CHECK: risbg {{%r[0-9]+}}, [[VALUE]], 32, 47, 16
+; CHECK: br %r14
+;
+; CHECK-SHIFT: f2:
+; CHECK-SHIFT: br %r14
+  %res = atomicrmw xchg i16 *%src, i16 40000 seq_cst
+  ret i16 %res
+}