[Bug middle-end/44069] [4.5/4.6 Regression] optimization bug initializing from cast array

[rguenth at gcc dot gnu dot org]

--- Comment #6 from rguenth at gcc dot gnu dot org  2010-05-14 21:16 ---
We fold

  D.1794_14 = D.1795_13 * 4;
  D.1793_15 = &vals[0][0] + D.1794_14;

to &vals[0][D.1795_13]

Now we can either avoid doing this kind of foldings or we need to be more
careful when analyzing the result in the oracle.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44069

[Bug middle-end/44069] [4.5/4.6 Regression] optimization bug initializing from cast array

[rguenth at gcc dot gnu dot org]

--- Comment #7 from rguenth at gcc dot gnu dot org  2010-05-14 21:28 ---
More reduced testcase:

template 
class M {
public:
M(const int* arr) {
for (unsigned long r = 0; r < R; ++r)
  for (unsigned long c = 0; c < C; ++c)
m[r*C+c] = arr[r*C+c];
}
int operator()(unsigned r, unsigned c) const
  { return m[r*C+c]; }
private:
int m[R*C];
};
extern "C" void abort (void);
int main()
{
  int vals[2][2] = { { 1, 2 }, { 5, 6 } };
  M<2,2> m( &(vals[0][0]) );
  if (m(1,0) != 5)
abort ();
  return 0;
}


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44069

[Bug middle-end/44069] [4.5/4.6 Regression] optimization bug initializing from cast array

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

   Priority|P3  |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44069

[Bug middle-end/44069] [4.5/4.6 Regression] optimization bug initializing from cast array

[rguenth at gcc dot gnu dot org]

--- Comment #8 from rguenth at gcc dot gnu dot org  2010-05-25 15:50 ---
Subject: Bug 44069

Author: rguenth
Date: Tue May 25 15:49:34 2010
New Revision: 159824

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159824
Log:
2010-05-25  Richard Guenther  

PR middle-end/44069
* gimple-fold.c (maybe_fold_stmt_addition): Avoid generating
out-of-bounds array accesses.

* g++.dg/torture/pr44069.C: New testcase.

Added:
trunk/gcc/testsuite/g++.dg/torture/pr44069.C
Modified:
trunk/gcc/ChangeLog
trunk/gcc/gimple-fold.c
trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44069