[clang] [X86]Add support for _outp{|w|d} (PR #93774)

[Phoebe Wang via cfe-commits]

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@@ -329,6 +329,26 @@ static __inline__ void __DEFAULT_FN_ATTRS __stosq(unsigned __int64 *__dst,
 static __inline__ void __DEFAULT_FN_ATTRS __halt(void) {
   __asm__ volatile("hlt");
 }
+
+static __inline__ int __DEFAULT_FN_ATTRS _outp(unsigned short port, int data) {
+  __asm__ volatile("outb %b0, %w1" : : "a"(data), "Nd"(port) : "memory");
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phoebewang wrote:

Instruction doesn't clobber memory.

https://github.com/llvm/llvm-project/pull/93774