Re: Floating-point comparisons in the middle-end

[FX via Gcc]

> Presumably that can be reproduced without depending on the new built-in 
> function?  In which case it's an existing bug somewhere in the optimizers.

Yes:

$ cat a.c
#include <math.h>
#include <stdio.h>
#include <fenv.h>

void foo (void) {
  if (fetestexcept (FE_INVALID) & FE_INVALID)
    printf("Invalid raised\n");
  feclearexcept (FE_ALL_EXCEPT);
}

static inline int iseqsig(float x, float y) { return (x >= y && x <= y); }

int main (void) {
  float x = __builtin_nanf("");
  float y;

  printf("%d\n", iseqsig(__builtin_nanf(""), 1.));
  foo();

  printf("%d\n", iseqsig(x, __builtin_inff()));
  foo();
}

$ ./bin/gcc a.c -lm -fno-unsafe-math-optimizations -frounding-math 
-fsignaling-nans -O0 && ./a.out
0
Invalid raised
0
Invalid raised

$ ./bin/gcc a.c -lm -fno-unsafe-math-optimizations -frounding-math 
-fsignaling-nans -O1 && ./a.out
0
0


Do you want me to file a bug report?

FX