[Bug middle-end/85586] [8/9 Regression] Optimizer produces different result on -O2 and -O3

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85586

--- Comment #3 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> 
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Testing a patch.