[Bug tree-optimization/85168] ICE in tree-ssa-coalesce.c: SSA corruption: Unable to coalesce ssa_names which are marked as MUST COALESCE when -O2 is used

[ivo.raisr at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85168

Ivo Raisr <ivo.raisr at oracle dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |ivo.raisr at oracle dot com

--- Comment #1 from Ivo Raisr <ivo.raisr at oracle dot com> ---
Debug output for rtl-expand shows:
...

Partition map 

Partition 0 (h_5(ab) - 5 )
Partition 1 (h_6(ab) - 6 )
Partition 2 (h_7 - 7 )
Partition 3 (h_12(ab) - 12 )
Partition 4 (h_14(ab) - 14 )
Partition 5 (h_20 - 20 )
Partition 6 (pretmp_21 - 21 )
Partition 7 (pretmp_22 - 22 )
Partition 8 (pretmp_23 - 23 )
Partition 9 (prephitmp_24 - 24 )


Conflict graph:
3: 4
4: 3

...

Abnormal coalesce: (6)h_6(ab) & (12)h_12(ab) [map: 1, 3] : Success -> 1
Abnormal coalesce: (6)h_6(ab) & (14)h_14(ab) [map: 1, 4] : Fail due to conflict


I am not sure if the conflict is because h_12 and h_14 are still live at the
same time or that h_7 and h_20 are not marked abnormal.