An accelerator manager monitors run-time performance of multiple accelerators in one or more programmable devices, and when first and second accelerators satisfy at least one coalescence criterion, the accelerator manager generates a new accelerator image corresponding to a third accelerator that coalesces the first accelerator and the second accelerator. In a first embodiment, the accelerator manager generates the new accelerator image from the accelerator images for the first and second accelerators. In a second embodiment, the accelerator manager generates the new accelerator image from hardware description language representations of the first and second accelerators. The new accelerator image is deployed to a programmable device to provide a new accelerator, and calls to the first and second accelerators are replaced with calls to the new accelerator.