[clang] [CIR][X86]Implement handling for Select/Selectsh builtins in CIR (PR #174003)

[Priyanshu Kumar via cfe-commits]

================
@@ -184,6 +184,37 @@ static mlir::Value emitX86Select(CIRGenBuilderTy &builder, mlir::Location loc,
   return cir::VecTernaryOp::create(builder, loc, mask, op0, op1);
 }
 
+static mlir::Value emitX86ScalarSelect(CIRGenBuilderTy &builder,
+                                       mlir::Location loc, mlir::Value mask,
+                                       mlir::Value op0, mlir::Value op1) {
+
+  // If the mask is all ones just return first argument.
+  if (auto c = mlir::dyn_cast_or_null<cir::ConstantOp>(mask.getDefiningOp()))
+    if (c.isAllOnesValue())
+      return op0;
+  // Cast to cir::IntType to safely get the width of a CIR integer
+  unsigned width = 0;
+  if (auto intTy = mlir::dyn_cast<cir::IntType>(mask.getType())) {
+    width = intTy.getWidth();
+  } else {
+    // Fallback or handle unexpected type
+    width = 8;
----------------
Priyanshu3820 wrote:

yes, that would be better. Done

https://github.com/llvm/llvm-project/pull/174003