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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/103254] [12 Regression] Compile time hog in
 compare_values_warnv since r12-4790-g4b3a325f07acebf4
Date: Thu, 18 Nov 2021 16:34:53 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103254

--- Comment #3 from Andrew Macleod <amacleod at redhat dot com> ---
This is a long sequence, made from the following pattern:

  _156 =3D _155 & _147;
  _157 =3D (int) _156;
  j_158 =3D _157 & j_149;
  _164 =3D (short int) j_158;
  _165 =3D _164 & _156;

Since GORI doesn't yet cache anything, each name evaluation is a "new" requ=
est.
 to resolve _165 it calculates  _164 and _156.
Note that _164 is also ultimately defined by _156 (in combination with _j_1=
49).
so that means we evaluate _156 twice to get _165.

This rapidly triggers the same exponential growth we encountered with PR
100081, so we will need to limit this sort of thing in general until GORI
starts caching outgoing values.=