riscv: Add codegen test for TLS stack canary

Make sure the code generated for a TLS-relative stack guard canary
references the right location before and after intervening function
code.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

llvm/test/CodeGen/RISCV/stack-guard-tls.ll

@@ -0,0 +1,19 @@
+; RUN: llc -mtriple=riscv64-unknown-elf < %s | \
+; RUN: FileCheck %s
+
+declare void @baz(ptr)
+
+define void @foo(i64 %t) sspstrong {
+  %vla = alloca i32, i64 %t, align 4
+  call void @baz(ptr nonnull %vla)
+  ret void
+}
+
+!llvm.module.flags = !{!0, !1, !2}
+!0 = !{i32 2, !"stack-protector-guard", !"tls"}
+!1 = !{i32 1, !"stack-protector-guard-reg", !"tp"}
+!2 = !{i32 2, !"stack-protector-guard-offset", i32 500}
+
+; CHECK: ld [[REG1:.*]], 500(tp)
+; CHECK: call baz
+; CHECK: ld [[REG2:.*]], 500(tp)