[RISCV] Add a test for multiple save locations of a callee-saved register

[mgudim]

Technically, it is possible that the a callee-saved register is saved in different locations. CFIInstrInserter should handle this, but currently it does not.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Mikhail Gudim (mgudim)

Changes

Technically, it is possible that the a callee-saved register is saved in different locations. CFIInstrInserter should handle this, but currently it does not.

---

Full diff: https://github.com/llvm/llvm-project/pull/164479.diff

1 Files Affected:

• (added) llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir (+35)

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
+...

[topperc]

Please put [RISCV] in the title as is the convention. I have email filters set up on various tags as I'm sure others do.

[lenary]

Can you not use "CSR" in the title? CSR has a specific RISC-V meaning, as well as not actually differentiating between "caller-saved register" and "callee-saved register".

[dyung]

I believe this test is causing test errors because it generates a .s file with no RUN lines causing problems when trying to run tests:
https://lab.llvm.org/buildbot/#/builders/202/builds/4244

******************** TEST 'LLVM :: CodeGen/RISCV/cfi-multiple-locations.s' FAILED ********************
Test has no 'RUN:' line
********************

Other tests that I can see using llc write the output to stdout and then pipe it to FileCheck, neither of which this test does. If you do not care about the actual output file, can we maybe send the output to /dev/null or something similar instead to avoid this problem?

[lenary]

I believe this test is causing test errors because it generates a .s file with no RUN lines causing problems when trying to run tests: https://lab.llvm.org/buildbot/#/builders/202/builds/4244

******************** TEST 'LLVM :: CodeGen/RISCV/cfi-multiple-locations.s' FAILED ********************
Test has no 'RUN:' line
********************

Other tests that I can see using llc write the output to stdout and then pipe it to FileCheck, neither of which this test does. If you do not care about the actual output file, can we maybe send the output to /dev/null or something similar instead to avoid this problem?

It's hard to solve this immediately, as evidently you're not cleaning up the source directory before builds. This test should no longer be being run at all, but evidently the .s from when it was being run has stuck around in your source directory.