Attachment 617789 Details for Bug 860853 – A reduced test case for the problem.

A reduced test case for the problem.

glibc-sign-issue.cpp (text/x-c++src), 1.11 KB, created by Martin Brain on 2012-09-26 21:12:29 UTC

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Creator: Martin Brain

Created: 2012-09-26 21:12:29 UTC

Size: 1.11 KB

patch

obsolete

>/*
>** g++ -frounding-math -fsignaling-nans -mfpmath=sse glibc-sign-issue.cpp -o glibc-sign-issue
>*/
>
>#include <assert.h>
>#include <math.h>
>
>#include <iostream>
>
>// From math/s_fmaf.c
>float
>__fmaf (float x, float y, float z)
>{
>  return (x * y) + z;
>}
>
>// From math/s_fma.c
>double
>__fma (double x, double y, double z)
>{
>  return (x * y) + z;
>}
>
>
>int main (void) {
>  float f1 = 0.0f;
>  float f2 = -1.0f;
>  float f3 = -0.0f;
>
>  float fmafresult = fmaf(f1,f2,f3);
>  double fmaresult = fma(double(f1),double(f2),double(f3));
>  float convert = double(fmaresult);
>
>  std::cout << fmafresult << "==" << fmaresult << '\t';
>
>  if (signbit(fmafresult) == signbit(convert)) {
>    std::cout << "match";
>  } else {
>    std::cout << "don't match";
>  }
>  std::cout << std::endl;
>
>
>  float lfmafresult = __fmaf(f1,f2,f3);
>  double lfmaresult = __fma(double(f1),double(f2),double(f3));
>  float lconvert = double(lfmaresult);
>
>  std::cout << lfmafresult << "==" << lfmaresult << '\t';
>
>  if (signbit(lfmafresult) == signbit(lconvert)) {
>    std::cout << "match";
>  } else {
>    std::cout << "don't match";
>  }
>  std::cout << std::endl;
>
>
>
>
>  return 0;
>}

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Attachments on bug 860853: 617789