Read this exception report line and tell me what happened: From { A B C }, To D, Setup 2, Hold *, Ignored f,o.

Short Answer

A set_multicycle_path 2 -from {A B C} -to D (SDC) was only partly applied. The f code means one startpoint, C, was invalid and got dropped; the o code means another path, A-to-D, was overridden by a higher-priority exception. Only B-to-D actually carries the multicycle value of 2.

Technical Explanation

The report line reads { A B C }, D, 2, , f,o — startpoints A, B, and C into endpoint D, a setup value of 2, no hold value (shown as ), and an Ignored column carrying two letter codes. That combination, read from report_exceptions (PT), tells you set_multicycle_path 2 -from {A B C} -to D (SDC) was accepted syntactically but only partly took effect.

• The f code: at least one named startpoint is invalid for this kind of exception — here, C — so the C-to-D path is dropped from the exception entirely, not applied at all.
• The o code: at least one path was overridden by a higher-priority exception — here, A-to-D, which some other command already covers, for instance a false path, and a false path outranks a multicycle path in the tool's exception precedence order.
• What's actually left: only B-to-D, which is the sole path enforced with the multicycle value of 2.
• The reading skill this tests: a command being accepted without a syntax error doesn't mean the whole thing took effect — of the three startpoints written, one was never valid, one is excused by something stronger, and only one behaves as intended.
• Why the Ignored column matters most: every field in the line is informative, but the Ignored column is the one that tells you the command's real, as-applied scope rather than its as-written scope.

Follow-up Question & Model Response

If you wanted the A-to-D path to actually get the multicycle relaxation despite the existing false path, what would you need to change?

Candidate Model Response: You'd need to remove or narrow the false path that currently covers A-to-D, since a multicycle path can't outrank a false path in the precedence order regardless of how it's written. If A-to-D genuinely shouldn't be a false path anymore, for example because a design change made it a real, timed path again, the fix is to update the false-path exception's scope so it no longer includes A-to-D, then let the multicycle command take effect on that path. Simply repeating or reordering the multicycle command won't change the precedence outcome.