cherryger.blogg.se - Visual studio code vs visual studio 2017

It is one of the fundamental optimizations and usually helps both in improving execution speed and reducing code size.

An extended collection of patterns that simplify code further and help reduce code size.Ĭommon Sub-Expression Elimination and Partially Redundancy Elimination overhaulĬommon Sub-expression Elimination (CSE) is an optimization that removes redundant code by identifying identical expressions and keeping one instance, replacing the others with the precomputed value.

Expressions using address-taken variables and indirect memory loads are better handled by using an aliased SSA form and value-numbering of loads (identifies memory locations with the same value).

This allows it to take advantage of new opportunities exposed by loop optimizations and other second-order effects.

The SSA Optimizer now runs twice, before and after the loop optimizer.

There are several general improvements available in the latest compiler release: As anticipated, it allowed us to make a significant amount of progress in a short time, a large part of the optimizations described here being implemented inside the framework. The SSA Optimizer is a new framework introduced last year in Visual Studio 2015 Update 3 that operates on Static Single Assignment form. General improvements to the SSA Optimizer The following sections of this post will go through some of the new optimizations and improvements that are being made available with the latest version, hopefully giving an interesting overview over the internal working of a modern native compiler backend. Compared to VS2015 Update 3, VS2017 15.5 provides on average an 8.9% increase in runtime speed in the SPEC 2017 benchmark (for detailed numbers see slide 12 from the CppCon presentation or the CppCon session video ).

In this post, we’d like to give you an update on the significant progress the Visual C++ code optimizer made in the past year, focused mostly on the features released in the 15.3 and 15.5 versions.