Compiler

2 articles

Software Engineering 19 Sep 2026 5 min read

LLVM Poison Values Defer Undefined Behavior Through the IR

LLVM IR does not turn every invalid arithmetic or pointer condition into immediate undefined behavior. Many instructions produce a poison value instead. That value can flow through later instructions, preserving the optimizer’s ability to rely on promises such as “this addition does not overflow” without forcing undefined behavior at the exact instruction where the promise is violated. This is part of LLVM’s semantics, not an optimizer implementation detail. A frontend that emits nsw, nuw, inbounds, noundef, or related constraints is stating facts that later passes may trust.

Software Engineering LLVM

Go 04 Sep 2026 9 min read

Understand Escape Analysis and Heap Allocations in Go

A Go program can create many values without you choosing whether each value lives on a goroutine stack or in heap memory. The compiler usually makes that decision for you. This becomes important when a hot path allocates more than expected. A small helper function may look harmless, yet a value it creates can outlive the function call and require heap storage. More heap allocation can mean more work for the garbage collector, but changing code blindly to avoid the heap can make a program harder to understand without producing a measurable benefit.

Golang Performance