case-study

2 posts

Metamorphic testing found 147 compiler bugs and a self-driving car defect. Here's how it works.

Metamorphic testing has uncovered real bugs in GCC, LLVM, Vulkan shader compilers, and ADAS simulators.

Metamorphic testing has found 147 confirmed bugs in GCC and LLVM, defects in commercial ADAS simulators used by automotive OEMs, and a fatal flaw in a…

August 16, 2026

cleanroom-correctness zero-defects verification case-study

Did anyone actually verify 10,000 lines with zero defects? IBM did, and the methodology is stranger than the result.

Cleanroom software engineering promised zero-defect increments through mathematical verification instead of debugging.

The software industry average in the 1980s was 30 to 60 defects per thousand lines of code. IBM's Cleanroom team shipped a 20,000-line compiler increment with…

July 25, 2026