[NFC][RISCV] Add test showing wrong stack slot for GPR and RVV spilled registers

[rogfer01]

Summary

This testcase shows that we attempt to assign the same offset sp + 16 to two different stack objects.

The fix will come in a later change.

[rogfer01]

ChangeLog:

• Simplify the MIR input
• Split test in two for RV32 and RV64

[frasercrmck]

I'm wondering if the commit message should indicate it's adding a test for the issue (though I realise space is at a premium). I was a bit confused at first.

llvm/test/CodeGen/RISCV/rvv/wrong-stack-slot-rv32.mir

22

nit: opening brace on a new line is a bit unusual?

[rogfer01]

ChangeLog:

• Clarify the purpose of the change.
• Adjust syntax of the IR input.

[frasercrmck]

LGTM though (sorry) maybe the tests could have a short comment explaining what they're testing (since they'll be fixed by a future patch anyway) and what to be wary of when the output changes.

[rogfer01]

ChangeLog:

• Describe a bit better the purpose of the test.

[rogfer01]

In D98801#2644290, @frasercrmck wrote:

LGTM though (sorry) maybe the tests could have a short comment explaining what they're testing (since they'll be fixed by a future patch anyway) and what to be wary of when the output changes.

Sure, no problem. Thanks!

llvm/test/CodeGen/RISCV/rvv/wrong-stack-slot-rv32.mir

+# NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+# RUN: llc -mtriple=riscv32 -mattr=+m,+experimental-v  -o - %s \
+# RUN:   -start-before=prologepilog | FileCheck %s
+#
+# This test checks that we are assigning the right stack slot to GPRs and to
+# vector registers (VRs). If this test changes, make sure there is no overlap
+# between slots for GPRs and VRs.
+--- |
+  define void @foo() #0 {
+  ; CHECK-LABEL: foo:
+  ; CHECK:       # %bb.0: # %entry
+  ; CHECK-NEXT:    addi sp, sp, -16
+  ; CHECK-NEXT:    sw s9, 12(sp) # 4-byte Folded Spill
+  ; CHECK-NEXT:    csrr a1, vlenb
+  ; CHECK-NEXT:    slli a1, a1, 1
+  ; CHECK-NEXT:    sub sp, sp, a1
+  ; CHECK-NEXT:    sw a0, 8(sp) # 4-byte Folded Spill
+  ; CHECK-NEXT:    vs2r.v v30, (sp) # Unknown-size Folded Spill
+  ; CHECK-NEXT:    csrr a0, vlenb
+  ; CHECK-NEXT:    slli a0, a0, 1
+  ; CHECK-NEXT:    add sp, sp, a0
+  ; CHECK-NEXT:    lw s9, 12(sp) # 4-byte Folded Reload
+  ; CHECK-NEXT:    addi sp, sp, 16
+  ; CHECK-NEXT:    ret
+  entry:
+    ret void
+  }
+
+  attributes #0 = { nounwind }
+...
+---
+name:            foo
+alignment:       2
+frameInfo:
+  maxAlignment:    8
+stack:
+  - { id: 0, type: spill-slot, size: 4, alignment: 4 }
+  - { id: 1, type: spill-slot, size: 16, alignment: 8, stack-id: scalable-vector }
+machineFunctionInfo: {}
+body:             |
+  bb.0.entry:
+    liveins: $x10, $v30m2
+
+    $x25 = COPY $x10
+    SW renamable $x25, %stack.0, 0 :: (store 4 into %stack.0)
+    PseudoVSPILL_M2 renamable $v30m2, %stack.1 :: (store unknown-size into %stack.1, align 8)
+    PseudoRET
+
+...

llvm/test/CodeGen/RISCV/rvv/wrong-stack-slot-rv64.mir

+# NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+# RUN: llc -mtriple=riscv64 -mattr=+m,+experimental-v  -o - %s \
+# RUN:   -start-before=prologepilog | FileCheck %s
+#
+# This test checks that we are assigning the right stack slot to GPRs and to
+# vector registers (VRs). If this test changes, make sure there is no overlap
+# between slots for GPRs and VRs.
+--- |
+  define void @foo() #0 {
+  ; CHECK-LABEL: foo:
+  ; CHECK:       # %bb.0: # %entry
+  ; CHECK-NEXT:    addi sp, sp, -32
+  ; CHECK-NEXT:    sd s9, 24(sp) # 8-byte Folded Spill
+  ; CHECK-NEXT:    csrr a1, vlenb
+  ; CHECK-NEXT:    slli a1, a1, 1
+  ; CHECK-NEXT:    sub sp, sp, a1
+  ; CHECK-NEXT:    sd a0, 16(sp) # 8-byte Folded Spill
+  ; CHECK-NEXT:    addi a0, sp, 16
+  ; CHECK-NEXT:    vs2r.v v30, (a0) # Unknown-size Folded Spill
+  ; CHECK-NEXT:    csrr a0, vlenb
+  ; CHECK-NEXT:    slli a0, a0, 1
+  ; CHECK-NEXT:    add sp, sp, a0
+  ; CHECK-NEXT:    ld s9, 24(sp) # 8-byte Folded Reload
+  ; CHECK-NEXT:    addi sp, sp, 32
+  ; CHECK-NEXT:    ret
+  entry:
+    ret void
+  }
+
+  attributes #0 = { nounwind }
+...
+---
+name:            foo
+alignment:       2
+tracksRegLiveness: true
+frameInfo:
+  maxAlignment:    8
+stack:
+  - { id: 0, type: spill-slot, size: 8, alignment: 8 }
+  - { id: 1, type: spill-slot, size: 16, alignment: 8, stack-id: scalable-vector }
+machineFunctionInfo: {}
+body:             |
+  bb.0.entry:
+    liveins: $x10, $v30m2
+
+    $x25 = COPY $x10
+    SD renamable $x25, %stack.0, 0 :: (store 8 into %stack.0)
+    PseudoVSPILL_M2 renamable $v30m2, %stack.1 :: (store unknown-size into %stack.1, align 8)
+    PseudoRET
+
+...