1 files changed, 36 insertions, 0 deletions
diff --git a/test/CodeGen/X86/tail-call-win64.ll b/test/CodeGen/X86/tail-call-win64.ll
new file mode 100644
index 0000000..23e9280
--- /dev/null
+++ b/test/CodeGen/X86/tail-call-win64.ll
@@ -0,0 +1,36 @@
+; RUN: llc -mtriple=x86_64-windows -show-mc-encoding < %s | FileCheck %s
+
+; The Win64 ABI wants tail jmps to use a REX_W prefix so it can distinguish
+; in-function jumps from function exiting jumps.
+
+define void @tail_jmp_reg(i32, i32, void ()* %fptr) {
+  tail call void ()* %fptr()
+  ret void
+}
+
+; Check that we merge the REX prefixes into 0x49 instead of 0x48, 0x41.
+
+; CHECK-LABEL: tail_jmp_reg:
+; CHECK: rex64 jmpq *%r8
+; CHECK: 	encoding: [0x49,0xff,0xe0]
+
+declare void @tail_tgt()
+
+define void @tail_jmp_imm() {
+  tail call void @tail_tgt()
+  ret void
+}
+
+; CHECK-LABEL: tail_jmp_imm:
+; CHECK: rex64 jmp tail_tgt
+
+@g_fptr = global void ()* @tail_tgt
+
+define void @tail_jmp_mem() {
+  %fptr = load void ()** @g_fptr
+  tail call void ()* %fptr()
+  ret void
+}
+
+; CHECK-LABEL: tail_jmp_mem:
+; CHECK: rex64 jmpq *g_fptr(%rip)