[SystemZ] Add support for 128-bit atomic load/store/cmpxchg

This adds support for the main 128-bit atomic operations,
using the SystemZ instructions LPQ, STPQ, and CDSG.

Generating these instructions is a bit more complex than usual
since the i128 type is not legal for the back-end.  Therefore,
we have to hook the LowerOperationWrapper and ReplaceNodeResults
TargetLowering callbacks.

llvm-svn: 310094

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/SystemZ/atomic-load-05.ll b/llvm/test/CodeGen/SystemZ/atomic-load-05.ll
new file mode 100644
index 00000000000..c527184ff23
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/atomic-load-05.ll
@@ -0,0 +1,13 @@
+; Test 128-bit atomic loads.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+
+define i128 @f1(i128 *%src) {
+; CHECK-LABEL: f1:
+; CHECK: lpq %r0, 0(%r3)
+; CHECK-DAG: stg %r1, 8(%r2)
+; CHECK-DAG: stg %r0, 0(%r2)
+; CHECK: br %r14
+  %val = load atomic i128, i128 *%src seq_cst, align 16
+  ret i128 %val
+}