[PATCH] D120592: [X86] Preserve redundant Address-Size override prefix

Thu Mar 3 10:59:16 PST 2022

Amir marked an inline comment as done.
Amir added inline comments.

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Comment at: llvm/test/MC/X86/index-operations.s:74
 stos %rax, (%edi)
-// 64: 	stosq %rax, %es:(%edi) # encoding: [0x48,0x67,0xab]
 // ERR32: only available in 64-bit mode
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Amir wrote:
> craig.topper wrote:
> > Was this a bug before? REX prefix is supposed to be the byte before the opcode.
> You're right. It was a bug before, but it's still there:
> REX prefix emission happened before emitSegmentOverridePrefix and 0x67 prefix, this diff moved 0x67 prefix emission above.
> See the line
> `    HasREX = emitOpcodePrefix(MemoryOperand, MI, STI, OS);`
> 
Addressed this issue in D120871 (follow-up to this diff)

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D120592/new/

https://reviews.llvm.org/D120592