[clang] [llvm] [X86] Support EGPR for inline assembly. (PR #92338)

[Shengchen Kan via cfe-commits]

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@@ -5394,10 +5394,12 @@ X86:
 - ``Z``: An immediate 32-bit unsigned integer.
 - ``q``: An 8, 16, 32, or 64-bit register which can be accessed as an 8-bit
   ``l`` integer register. On X86-32, this is the ``a``, ``b``, ``c``, and ``d``
-  registers, and on X86-64, it is all of the integer registers.
+  registers, and on X86-64, it is all of the integer registers. When feature
+  `egpr` and `inline-asm-use-gpr32` are both on, they will be extended to EGPR.
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KanRobert wrote:

EGPR -> gp32

EGPR refers to r16-r31.

https://github.com/llvm/llvm-project/pull/92338