[llvm] [RISCV] Add a test for multiple save locations of a CSR. (PR #164479)

[Mikhail Gudim via llvm-commits]

https://github.com/mgudim updated https://github.com/llvm/llvm-project/pull/164479

>From 4f5d8e082547b285b619839e3797c84e01bc2aa2 Mon Sep 17 00:00:00 2001
From: Mikhail Gudim <mgudim at ventanamicro.com>
Date: Wed, 2 Apr 2025 08:22:37 -0700
Subject: [PATCH] [RISCV] Add a test for multiple save locations of a CSR.

Technically, it is possible that the a callee-saved register is saved
in different locations. CFIInstrInserter should handle this, but
currently it does not.
---
 .../CodeGen/RISCV/cfi-multiple-locations.mir  | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir

diff --git a/llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir b/llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir
new file mode 100644
index 0000000000000..075536e10bce6
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir
@@ -0,0 +1,35 @@
+# RUN: llc %s -mtriple=riscv64 \
+# RUN: -run-pass=cfi-instr-inserter \
+# RUN: -riscv-enable-cfi-instr-inserter=true
+# XFAIL: *
+
+# Technically, it is possible that the a callee-saved register is saved in different locations.
+# CFIInstrInserter should handle this, but currently it does not.
+---
+name: multiple_locations
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x9, $x2
+    BEQ $x10, $x0, %bb.3
+    PseudoBR %bb.2
+
+  bb.1:
+    liveins: $x10, $x9, $x2
+    $x5 = COPY $x9
+    CFI_INSTRUCTION register $x9, $x5
+    $x9 = COPY $x5
+    CFI_INSTRUCTION register $x9, $x9
+    PseudoBR %bb.3
+
+  bb.2:
+    liveins: $x10, $x9, $x2
+    SD $x9, $x2, 0 :: (store (s64))
+    CFI_INSTRUCTION offset $x9, 0
+    $x9  = LD $x2, 0 :: (load (s64))
+    CFI_INSTRUCTION register $x9, $x9
+    PseudoBR %bb.3
+
+  bb.3:
+    PseudoRET
+...