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open: skip CRPR pre-CTS to avoid OOM on high-reconvergence clocks #4284

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open: skip CRPR pre-CTS to avoid OOM on high-reconvergence clocks #4284

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6 changes: 6 additions & 0 deletions flow/scripts/open.tcl
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,12 @@ proc read_timing { input_file } {
if { $design_stage >= 4 } {
# CTS has run, so propagate clocks
set_propagated_clock [all_clocks]
Comment on lines 53 to 55

@gemini-code-assist gemini-code-assist Bot Jun 9, 2026

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medium

To ensure robustness in interactive sessions or when read_timing is called multiple times in the same persistent session (such as in the GUI or custom scripts), it is recommended to explicitly enable CRPR when $design_stage >= 4. Otherwise, if a pre-CTS design was loaded first (which disables CRPR), loading a post-CTS design later in the same session will leave CRPR disabled.

  if { $design_stage >= 4 } {
    # CTS has run, so propagate clocks
    set_propagated_clock [all_clocks]
    sta::set_crpr_enabled 1

@oharboe oharboe Jun 9, 2026

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That's a bridge too far, I don't think that's a real use-case.

} else {
# Pre-CTS there is no clock tree, so CRPR has no real launch/capture
# common-path delay to remove and its correction is ~0. On designs with
# high clock reconvergence the CRPR tag set can still grow to tens of GB
# and OOM the process. Skip it pre-CTS.
sta::set_crpr_enabled 0
}

if { $design_stage >= 6 && [file exist $::env(RESULTS_DIR)/6_final.spef] } {
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