Coalescing global completion table entries in an out-of-order processor

Aspects of the invention include detecting that all instructions in a first group of in-flight instructions have a status of finished. The first group of in-flight instructions is associated with a first allocated entry in a global completion table (GCT) which tracks a dispatch order and status of groups of in-flight instructions. The GCT includes a plurality of allocated entries including the first allocated entry and a second allocated entry. A second group of in-flight instructions dispatched immediately prior to the first group is associated with the second allocated entry in the GCT. Based at least in part on the detecting, the first allocated entry is merged into the second allocated entry to create a single merged second allocated entry in the GCT that includes completion information for both the first group of in flight instructions and the second group of in-flight instructions. The first allocated entry is then deallocated.