[llvm] [X86][MC] Support Enc/Dec for EGPR for promoted CRC32 (PR #76434)

[Phoebe Wang via llvm-commits]

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@@ -6698,6 +6698,30 @@ let Constraints = "$src1 = $dst" in {
     def CRC32r64r8 : SS42I_crc32r<0xF0, "crc32{b}", GR64, GR8,
                                    null_frag>, REX_W;
   }
+
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phoebewang wrote:

@KanRobert said we need `In64BitMode` even for assembler?

https://github.com/llvm/llvm-project/pull/76434