On Fri, Sep 5, 2014 at 3:00 AM, Richard Biener <rguent...@suse.de> wrote: > > The following patch adds sanity checking for loops removed > via mark_loop_for_removal or fix_loop_structure to check > whether they reappear in the same place. > > The simplest case is where the loop header stays the same > and we definitely should avoid all these cases. > > The other case is where the old header becomes part of > a newly discovered loop. That happens when you rotate > a loop for example. > > The interesting bits of this are the new former_header field > in struct loop which holds onto the old header basic-block > so that even when it gets discarded its memory will not be > reused. For the sanity checking we can then verify if > it is still a basic-block in the current function. > > In theory we might be able to "autodetect" some loop > rotation cases as well as "restore" bogusly removed loops. > I'll see what the best solution is here after I (or somebody > else) has some testcases to look at. > > Bootstrap and regtest running on x86_64-unknown-linux-gnu. > > Richard. > > 2014-09-05 Richard Biener <rguent...@suse.de> > > * cfgloop.c (mark_loop_for_removal): Record former header > when ENABLE_CHECKING. > * cfgloop.h (strut loop): Add former_header member when > ENABLE_CHECKING. > * loop-init.c (fix_loop_structure): Sanity check loops > marked for removal if they re-appeared. >
I think it caused: FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer (internal compiler error) FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer (test for excess errors) FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer -funroll-loops (internal compiler error) FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer -funroll-loops (test for excess errors) FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer -funroll-all-loops -finline-functions (internal compiler error) FAIL: g++.dg/torture/pr57140.C -O3 -fomit-frame-pointer -funroll-all-loops -finline-functions (test for excess errors) FAIL: g++.dg/torture/pr57140.C -O3 -g (internal compiler error) FAIL: g++.dg/torture/pr57140.C -O3 -g (test for excess errors) on x86. -- H.J.
