mlir: fix incorrect usages of divideCeilSigned (#95680)

Follow up on #95087 to fix incorrect usage instances of
divideCeilSigned.

Author: artagnon

mlir/include/mlir/Dialect/Mesh/IR/MeshOps.h

@@ -114,7 +114,7 @@ inline int64_t shardDimension(int64_t dimSize, int64_t shardCount) {
     return ShapedType::kDynamic;
 
   assert(dimSize % shardCount == 0);
-  return llvm::divideCeilSigned(dimSize, shardCount);
+  return dimSize / shardCount;
 }
 
 // Get the size of an unsharded dimension.

mlir/lib/Conversion/LLVMCommon/MemRefBuilder.cpp

@@ -365,7 +365,7 @@ void UnrankedMemRefDescriptor::computeSizes(
   Value two = createIndexAttrConstant(builder, loc, indexType, 2);
   Value indexSize = createIndexAttrConstant(
       builder, loc, indexType,
-      llvm::divideCeilSigned(typeConverter.getIndexTypeBitwidth(), 8));
+      llvm::divideCeil(typeConverter.getIndexTypeBitwidth(), 8));
 
   sizes.reserve(sizes.size() + values.size());
   for (auto [desc, addressSpace] : llvm::zip(values, addressSpaces)) {
@@ -378,8 +378,7 @@ void UnrankedMemRefDescriptor::computeSizes(
     // to data layout) into the unranked descriptor.
     Value pointerSize = createIndexAttrConstant(
         builder, loc, indexType,
-        llvm::divideCeilSigned(typeConverter.getPointerBitwidth(addressSpace),
-                               8));
+        llvm::divideCeil(typeConverter.getPointerBitwidth(addressSpace), 8));
     Value doublePointerSize =
         builder.create<LLVM::MulOp>(loc, indexType, two, pointerSize);
 

mlir/lib/Conversion/MemRefToLLVM/MemRefToLLVM.cpp

@@ -971,7 +971,7 @@ struct MemorySpaceCastOpLowering
                                resultUnderlyingDesc, resultElemPtrType);
 
       int64_t bytesToSkip =
-          2 * llvm::divideCeilSigned(
+          2 * llvm::divideCeil(
                   getTypeConverter()->getPointerBitwidth(resultAddrSpace), 8);
       Value bytesToSkipConst = rewriter.create<LLVM::ConstantOp>(
           loc, getIndexType(), rewriter.getIndexAttr(bytesToSkip));