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From: "paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/48760] [4.6 / 4.7 Regression (?)] std::complex constructor buggy in the face of NaN's
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48760

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-25 12:41:59 UTC ---
PR24581 can be related, its additional, "unexpected", nans.

A C snippet showing the issue would be:

int main()
{
  float r = 0;
  float i = __builtin_nanf ("");

  __complex__ float c = r + i * 1.0fi; 

  /*
  __complex__ float c;
  __real__ c = r;
  __imag__ c = i;
  */

  __builtin_printf("%f\n", __real__ c);
  __builtin_printf("%f\n", __imag__ c);
}

Indeed, I could tweak the library to construct the complex by pieces, avoiding
the multiplication by the imaginary constant in the constructor, but the
problem would definitely reappear at any following multiplication...