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

[zhijian lin via cfe-commits]

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@@ -16542,12 +16542,64 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
 
   Intrinsic::ID ID = Intrinsic::not_intrinsic;
 
+  // The lambda function converts builtin_cpu_is function into directly
+  // returning false or true, or it gets and checks the information from the
+  // kernel variable _system_configuration for AIX OS.
+
+#include "llvm/TargetParser/PPCTargetParser.def"
+  auto ConvBuiltinCpu = [&](unsigned SupportMagic, unsigned FieldIdx,
+                            unsigned CompOp, unsigned OpValue) -> Value * {
+    if (SupportMagic == AIX_BUILTIN_PPC_FALSE)
+      return llvm::ConstantInt::getFalse(ConvertType(E->getType()));
+
+    if (SupportMagic == AIX_BUILTIN_PPC_TRUE)
+      return llvm::ConstantInt::getTrue(ConvertType(E->getType()));
+
+    assert(SupportMagic <= SYS_CONF && "Invalid value for SupportMagic.");
+    llvm::Type *STy = llvm::StructType::get(PPC_SYSTEMCONFIG_TYPE);
+
+    llvm::Constant *SysConf =
+        CGM.CreateRuntimeVariable(STy, "_system_configuration");
+
+    // Grab the appropriate field from _system_configuration.
+    llvm::Value *Idxs[] = {ConstantInt::get(Int32Ty, 0),
+                           ConstantInt::get(Int32Ty, FieldIdx)};
+
+    llvm::Value *FieldValue = Builder.CreateGEP(STy, SysConf, Idxs);
+    FieldValue = Builder.CreateAlignedLoad(Int32Ty, FieldValue,
+                                           CharUnits::fromQuantity(4));
+
+    assert((CompOp == COMP_EQ) && "Only equal comparisons are supported!");
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diggerlin wrote:

I moved the assert up and check earlier

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