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[Bug tree-optimization/81913] [8 Regression] wrong code at -O1
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 21 Aug 2017 10:59:45 +0000
- Subject: [Bug tree-optimization/81913] [8 Regression] wrong code at -O1
- Auto-submitted: auto-generated
- References: <bug-81913-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81913
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amker at gcc dot gnu.org,
| |rguenth at gcc dot gnu.org
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
It's SCEV const-prop aka final value replacement (and thus likely niter
analysis):
Analyzing # of iterations of loop 1
exit condition [0, + , 5] <= 0
bounds on difference of bases: 0 ... 0
result:
# of iterations 1, bounded by 1
Replacing uses of: e_5 with: 4266897156
gimple_simplified to if (1 != 0)