[llvm] [AMDGPU] Detect illegal 64 relocs in SIFold (PR #219141)

[Jay Foad via llvm-commits]

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@@ -5431,6 +5442,18 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
         ErrInfo = "illegal 64-bit immediate value for operand.";
         return false;
       }
+      // A global with a 64-bit relocation resolves to a 64-bit literal at link
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jayfoad wrote:

We already know we've got a 64-bit operand so you should not need to check whether it's a 64-bit reloc. 32-bit relocs should not be valid in the first place.

Also why do you need the checks for V_MOV_B64_PSEUDO and S_MOV_B64_IMM_PSEUDO here? (And if they are needed here, why aren't they needed in the 64-bit immediate case just above?)

https://github.com/llvm/llvm-project/pull/219141