[Bug middle-end/57393] [4.9 Regression] error: definition in block 4 follows the use / internal compiler error: verify_ssa failed

["d.g.gorbachev at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57393

--- Comment #7 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> ---
For convenience, I put here a testcase from bug 57400. Joost VandeVondele:
"this second testcase is almost certainly a dup of PR57393. It passes with
-fno-tree-reassoc. The testcase is conveniently smaller."

======================== 8< ========================
extern void bar(double);

struct S {
  int n;
};

void foo(struct S s, double a, int i, int j, int k)
{
  struct S t;
  bar(s.n * a * i * j);
  t.n = s.n * a * i * k;
}
======================== >8 ========================

$ gcc -S -g -O -ffast-math bug.c
bug.c: In function 'foo':
bug.c:7:6: error: definition in block 2 follows the use
 void foo(struct S s, double a, int i, int j, int k)
      ^
for SSA_NAME: _4 in statement:
# DEBUG D#3 => _4 * _6
bug.c:7:6: internal compiler error: verify_ssa failed
0x888c299 verify_ssa(bool)
    ../../gcc-4.9/gcc/tree-ssa.c:1046
0x85dc5ca execute_function_todo
    ../../gcc-4.9/gcc/passes.c:1970
0x85db901 do_per_function
    ../../gcc-4.9/gcc/passes.c:1707
0x85dc6df execute_todo
    ../../gcc-4.9/gcc/passes.c:2002
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GCC 4.9.0 20130630 (experimental).