[BUG] <title> FPU error behavior

[yutong0505]

Is there an existing CVA6 bug for this?

• [x] I have searched the existing bug issues

Bug Description

When using the FPU with NUM_OPGROUPS set to 4, if we issue FADD, FSQRT, and FCMP consecutively in different cycles, and two of these instructions complete execution simultaneously, the out_valid_o signal of one instruction drops before out_ready_i is asserted (G31 and G32 out_valid_o at the same time). This causes the commit process to be unable to commit that instruction.

Thanks for your help