--- title: Speculative Optimizations for WebAssembly using Deopts... description: V8 introduces two new WebAssembly optimizations in Chrome M137: speculative call_indirect inlining and deoptimization support. These optimizations use runtime... canonical: https://daily.dev/posts/speculative-optimizations-for-webassembly-using-deopts-and-inlining-v8-zof7whbeq twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Speculative Optimizations for WebAssembly using Deopts and Inlining · V8 | daily.dev og:description: V8 introduces two new WebAssembly optimizations in Chrome M137: speculative call_indirect inlining and deoptimization support. These optimizations use runtime... og:url: https://daily.dev/posts/speculative-optimizations-for-webassembly-using-deopts-and-inlining-v8-zof7whbeq og:image: https://api.daily.dev/og/posts/ZOf7whbEq.png og:image:alt: Speculative Optimizations for WebAssembly using Deopts and Inlining · V8 og:image:width: 1200 og:image:height: 630 og:locale: en --- [V8](https://daily.dev/sources/v8) [Read post](https://api.daily.dev/r/ZOf7whbEq) # [Speculative Optimizations for WebAssembly using Deopts and Inlining · V8](https://api.daily.dev/r/ZOf7whbEq "Go to post") V8 introduces two new WebAssembly optimizations in Chrome M137: speculative call\_indirect inlining and deoptimization support. These optimizations use runtime feedback to make assumptions and generate faster machine code, particularly benefiting WasmGC programs. The combination delivers 50%+ speedups on Dart microbenchmarks and 1-8% improvements on realistic applications. Speculative inlining replaces indirect calls with inlined function bodies when feedback shows monomorphic or polymorphic call patterns, while deoptimization allows graceful fallback to baseline code when assumptions prove incorrect, enabling more aggressive optimizations. [#compiler-optimization](/tags/compiler-optimization "Check all #compiler-optimization posts")[#performance](/tags/performance "Check all #performance posts")[#v8](/tags/v8 "Check all #v8 posts")[#webassembly](/tags/webassembly "Check all #webassembly posts") Jun 24, 2025•20m read time•From [v8.dev](https://api.daily.dev/r/ZOf7whbEq "v8.dev") [](https://api.daily.dev/r/ZOf7whbEq "Go to post") Table of contents [Background #](https://api.daily.dev/r/ZOf7whbEq?a=background "Background #")[Motivation #](https://api.daily.dev/r/ZOf7whbEq?a=motivation "Motivation #")[Speculative Inlining #](https://api.daily.dev/r/ZOf7whbEq?a=speculative-inlining "Speculative Inlining #")[Deoptimization #](https://api.daily.dev/r/ZOf7whbEq?a=deoptimization "Deoptimization #")[Results #](https://api.daily.dev/r/ZOf7whbEq?a=results "Results #")[Conclusion and Outlook #](https://api.daily.dev/r/ZOf7whbEq?a=conclusion-and-outlook "Conclusion and Outlook #") 38 Impressions Comment Bookmark Copy Share your thoughtsPost [](https://daily.dev/sources/v8) [V8](https://daily.dev/sources/v8 "https://daily.dev/sources/v8") The V8 Blog provides updates, technical deep dives, and insights on V8, Google's open-source JavaScr... Read more 15 Followers • 25 Upvotes #### Would you recommend this post? Copy link WhatsApp Facebook X New Squad Copy linkShare with your friends ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Speculative Optimizations for WebAssembly using Deopts and Inlining · V8","url":"https://daily.dev/posts/speculative-optimizations-for-webassembly-using-deopts-and-inlining-v8-zof7whbeq","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/speculative-optimizations-for-webassembly-using-deopts-and-inlining-v8-zof7whbeq"},"datePublished":"2025-06-24T14:49:27.142Z","dateModified":"2026-03-30T02:17:33.095Z","description":"V8 introduces two new WebAssembly optimizations in Chrome M137: speculative call_indirect inlining and deoptimization support. These optimizations use runtime...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/ad1b7c45766d3be91bb883830627b20a?_a=AQAEulh","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/ad1b7c45766d3be91bb883830627b20a?_a=AQAEulh","isAccessibleForFree":true,"articleSection":"V8","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"V8","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/0cc7af7d23ee41d395473fd298dad108","url":"https://daily.dev/sources/v8"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/speculative-optimizations-for-webassembly-using-deopts-and-inlining-v8-zof7whbeq","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"compiler-optimization,performance,v8,webassembly","timeRequired":"PT20M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"V8","item":"https://daily.dev/sources/v8"},{"@type":"ListItem","position":3,"name":"Speculative Optimizations for WebAssembly using Deopts and Inlining · V8"}]} ```