[CIR] Implement folder for VecCreateOp

clang/include/clang/CIR/Dialect/IR/CIROps.td

@@ -2059,6 +2059,7 @@ def VecCreateOp : CIR_Op<"vec.create", [Pure]> {
   }];
 
   let hasVerifier = 1;
+  let hasFolder = 1;
 }
 
 //===----------------------------------------------------------------------===//

clang/lib/CIR/Dialect/IR/CIRDialect.cpp

@@ -1533,6 +1533,16 @@ LogicalResult cir::GetMemberOp::verify() {
 // VecCreateOp
 //===----------------------------------------------------------------------===//
 
+OpFoldResult cir::VecCreateOp::fold(FoldAdaptor adaptor) {
+  if (llvm::any_of(getElements(), [](mlir::Value value) {
+        return !mlir::isa<cir::ConstantOp>(value.getDefiningOp());
+      }))
+    return {};
+
+  return cir::ConstVectorAttr::get(
+      getType(), mlir::ArrayAttr::get(getContext(), adaptor.getElements()));
+}
+
 LogicalResult cir::VecCreateOp::verify() {
   // Verify that the number of arguments matches the number of elements in the
   // vector, and that the type of all the arguments matches the type of the

clang/lib/CIR/Dialect/Transforms/CIRCanonicalize.cpp

@@ -142,7 +142,8 @@ void CIRCanonicalizePass::runOnOperation() {
     // Many operations are here to perform a manual `fold` in
     // applyOpPatternsGreedily.
     if (isa<BrOp, BrCondOp, CastOp, ScopeOp, SwitchOp, SelectOp, UnaryOp,
-            VecExtractOp, VecShuffleOp, VecShuffleDynamicOp, VecTernaryOp>(op))
+            VecCreateOp, VecExtractOp, VecShuffleOp, VecShuffleDynamicOp,
+            VecTernaryOp>(op))
       ops.push_back(op);
   });
 

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -901,6 +901,10 @@ mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
       rewriter.eraseOp(op);
       return mlir::success();
     }
+  } else if (const auto vecTy = mlir::dyn_cast<cir::VectorType>(op.getType())) {
+    rewriter.replaceOp(op, lowerCirAttrAsValue(op, op.getValue(), rewriter,
+                                               getTypeConverter()));
+    return mlir::success();
   } else {
     return op.emitError() << "unsupported constant type " << op.getType();
   }

clang/test/CIR/Transforms/vector-create-fold.cir

@@ -0,0 +1,19 @@
+// RUN: cir-opt %s -cir-canonicalize -o - | FileCheck %s
+
+!s32i = !cir.int<s, 32>
+
+module  {
+  cir.func @fold_create_vector_op_test() -> !cir.vector<4 x !s32i> {
+    %2 = cir.const #cir.int<1> : !s32i
+    %3 = cir.const #cir.int<2> : !s32i
+    %4 = cir.const #cir.int<3> : !s32i
+    %5 = cir.const #cir.int<4> : !s32i
+    %vec = cir.vec.create(%2, %3, %4, %5 : !s32i, !s32i, !s32i, !s32i) : !cir.vector<4 x !s32i>
+    cir.return %vec : !cir.vector<4 x !s32i>
+  }
+
+  // CHECK:  cir.func @fold_create_vector_op_test() -> !cir.vector<4 x !s32i> {
+  // CHECK-NEXT: %[[VEC:.*]] = cir.const #cir.const_vector<[#cir.int<1> : !s32i, #cir.int<2> : !s32i,
+  // CHECK-SAME: #cir.int<3> : !s32i, #cir.int<4> : !s32i]> : !cir.vector<4 x !s32i>
+  // CHECK-NEXT: cir.return %[[VEC]] : !cir.vector<4 x !s32i>
+}