Better: Keil Arm Compiler

| Compiler | Code size | Cycle count per iteration | |----------|-----------|----------------------------| | GCC -O2 | 14.2 KB | 128 cycles | | Keil AC6 -Oz | 10.8 KB | 112 cycles | | Keil AC6 -O3 | 12.1 KB | 96 cycles |

Have you migrated from AC5 to AC6? Or switched from GCC to Keil? Let me know in the comments – I’d love to hear your performance numbers. Want more embedded toolchain deep dives? Subscribe to the newsletter. keil arm compiler

But in an era of GCC, Clang, and cloud IDEs, does Keil’s compiler still matter? Absolutely. Let’s break down what makes it unique, when to choose it, and how to get the most out of it. It’s a C/C++ compiler specifically optimized for Arm Cortex-M , Cortex-R , and legacy Arm7/9 cores. Unlike generic compilers, it’s co-developed with Arm’s architecture team—giving it an insider’s edge. | Compiler | Code size | Cycle count