diff --git a/mlir/lib/Conversion/SPIRVToLLVM/ConvertSPIRVToLLVM.cpp b/mlir/lib/Conversion/SPIRVToLLVM/ConvertSPIRVToLLVM.cpp
--- a/mlir/lib/Conversion/SPIRVToLLVM/ConvertSPIRVToLLVM.cpp
+++ b/mlir/lib/Conversion/SPIRVToLLVM/ConvertSPIRVToLLVM.cpp
@@ -83,11 +83,12 @@
 /// Creates `llvm.mlir.constant` with all bits set for the given type.
 static Value createConstantAllBitsSet(Location loc, Type srcType, Type dstType,
                                       PatternRewriter &rewriter) {
-  if (srcType.isa<VectorType>())
+  if (srcType.isa<VectorType>()) {
     return rewriter.create<LLVM::ConstantOp>(
         loc, dstType,
         SplatElementsAttr::get(srcType.cast<ShapedType>(),
                                minusOneIntegerAttribute(srcType, rewriter)));
+  }
   return rewriter.create<LLVM::ConstantOp>(
       loc, dstType, minusOneIntegerAttribute(srcType, rewriter));
 }
@@ -239,7 +240,7 @@
   matchAndRewrite(spirv::BitFieldInsertOp op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override {
     auto srcType = op.getType();
-    auto dstType = this->typeConverter.convertType(srcType);
+    auto dstType = typeConverter.convertType(srcType);
     if (!dstType)
       return failure();
     Location loc = op.getLoc();
@@ -328,7 +329,7 @@
   matchAndRewrite(spirv::BitFieldSExtractOp op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override {
     auto srcType = op.getType();
-    auto dstType = this->typeConverter.convertType(srcType);
+    auto dstType = typeConverter.convertType(srcType);
     if (!dstType)
       return failure();
     Location loc = op.getLoc();
@@ -381,7 +382,7 @@
   matchAndRewrite(spirv::BitFieldUExtractOp op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override {
     auto srcType = op.getType();
-    auto dstType = this->typeConverter.convertType(srcType);
+    auto dstType = typeConverter.convertType(srcType);
     if (!dstType)
       return failure();
     Location loc = op.getLoc();
@@ -473,7 +474,7 @@
     }
 
     // Function returns a single result.
-    auto dstType = this->typeConverter.convertType(callOp.getType(0));
+    auto dstType = typeConverter.convertType(callOp.getType(0));
     rewriter.replaceOpWithNewOp<LLVM::CallOp>(callOp, dstType, operands,
                                               callOp.getAttrs());
     return success();
@@ -638,7 +639,7 @@
     auto funcType = funcOp.getType();
     TypeConverter::SignatureConversion signatureConverter(
         funcType.getNumInputs());
-    auto llvmType = this->typeConverter.convertFunctionSignature(
+    auto llvmType = typeConverter.convertFunctionSignature(
         funcOp.getType(), /*isVariadic=*/false, signatureConverter);
     if (!llvmType)
       return failure();
@@ -675,7 +676,10 @@
 
     rewriter.inlineRegionBefore(funcOp.getBody(), newFuncOp.getBody(),
                                 newFuncOp.end());
-    rewriter.applySignatureConversion(&newFuncOp.getBody(), signatureConverter);
+    if (failed(rewriter.convertRegionTypes(&newFuncOp.getBody(), typeConverter,
+                                           &signatureConverter))) {
+      return failure();
+    }
     rewriter.eraseOp(funcOp);
     return success();
   }