[llvm] [RISCV] Allow spilling to unused Zcmp Stack (PR #125959)

[Sam Elliott via llvm-commits]

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@@ -8,8 +8,8 @@ define ptr @func(ptr %s, i32 %_c, ptr %incdec.ptr, i1 %0, i8 %conv14) #0 {
 ; RV32-NEXT:    .cfi_offset ra, -12
 ; RV32-NEXT:    .cfi_offset s0, -8
 ; RV32-NEXT:    .cfi_offset s1, -4
-; RV32-NEXT:    addi sp, sp, -8
-; RV32-NEXT:    .cfi_def_cfa_offset 24
+; RV32-NEXT:    addi sp, sp, -4
+; RV32-NEXT:    .cfi_def_cfa_offset 20
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lenary wrote:

This stack pointer looks unaligned but it's not - because the whole test uses `ilp32e`

https://github.com/llvm/llvm-project/pull/125959