[clang] [llvm] [AIX] support builtin_cpu_is() for aix (PR #80069)

[zhijian lin via cfe-commits]

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@@ -126,4 +126,53 @@ PPC_LNX_CPU("power10",47)
 #undef PPC_LNX_DEFINE_OFFSETS
 #undef PPC_LNX_FEATURE
 #undef PPC_LNX_CPU
+
+// Definition of the following values are found in the AIX header file: <systemcfg.h>.
+#ifndef AIX_POWERPC_SYS_CONF
+#define AIX_POWERPC_SYS_CONF
+  #define AIX_SYSCON_IMPL_IDX 1
+  #define AIX_PPC7_VALUE 0x00008000
+  #define AIX_PPC8_VALUE 0x00010000
+  #define AIX_PPC9_VALUE 0x00020000
+  #define AIX_PPC10_VALUE 0x00040000
+
+  #define AIX_BUILTIN_PPC_TRUE 1
+  #define AIX_BUILTIN_PPC_FALSE 0
+  #define SYS_CONF 2
+
+  #define COMP_EQ  0
+
+#endif
+
+// When the value of SUPPORT_MAGIC is SYS_CONF, the return value depends on the 
+// _system_configuration[INDEX] COMPARE_OP VALUE.
+#ifndef PPC_AIX_CPU
+  #define PPC_AIX_CPU(NAME, SUPPORT_MAGIC, INDEX, COMPARE_OP, VALUE)
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diggerlin wrote:

we will have  API call in other patch later, I do not think change `INDEX` to `SYS_CFG_INDEX` and `VALUE` to `SYS_CFG_VALUE`  is a good idea.

https://github.com/llvm/llvm-project/pull/80069