vendor/llvm/llvm-release_360-r226102

1 files changed, 28 insertions, 0 deletions

diff --git a/test/CodeGen/X86/stackmap-shadow-optimization.ll b/test/CodeGen/X86/stackmap-shadow-optimization.ll
new file mode 100644
index 000000000000..a3725f2c5b72
--- /dev/null
+++ b/test/CodeGen/X86/stackmap-shadow-optimization.ll
@@ -0,0 +1,28 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck %s
+
+; Check that the X86 stackmap shadow optimization is only outputting a 3-byte
+; nop here. 8-bytes are requested, but 5 are covered by the code for the call to
+; bar.  However, the frame teardown and the return do not count towards the
+; stackmap shadow as the call return counts as a branch target so must flush
+; the shadow.
+; Note that in order for a thread to not return in to the patched space
+; the call must be at the end of the shadow, so the required nop must be
+; before the call, not after.
+define void @shadow_optimization_test() {
+entry:
+; CHECK-LABEL:  shadow_optimization_test:
+; CHECK:        callq   _bar
+; CHECK:        nop
+; CHECK:        callq   _bar
+; CHECK-NOT:    nop
+; CHECK:        callq   _bar
+; CHECK-NOT:    nop
+  call void @bar()
+  tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 8)
+  call void @bar()
+  call void @bar()
+  ret void
+}
+
+declare void @llvm.experimental.stackmap(i64, i32, ...)
+declare void @bar()