Some test: https://ideone.com/zkHHty
2018-05-18 13:36 GMT+02:00, Abroży Nieprzełoży
<abrozynieprzelozy314...@gmail.com>:
> --------------------------------------------------------
> 1: static int sqlite3IntFloatCompare(i64 i, double r){
> 2: if( sizeof(LONGDOUBLE_TYPE)>8 ){
> 3: LONGDOUBLE_TYPE x = (LONGDOUBLE_TYPE)i;
> 4: if( x<r ) return -1;
> 5: if( x>r ) return +1;
> 6: return 0;
> 7: }else{
> 8: i64 y;
> 9: double s;
> 10: if( r<-9223372036854775808.0 ) return +1;
> 11: if( r>9223372036854775807.0 ) return -1;
> 12: y = (i64)r;
> 13: if( i<y ) return -1;
> 14: if( i>y ){
> 15: if( y==SMALLEST_INT64 && r>0.0 ) return -1;
> 16: return +1;
> 17: }
> 18: s = (double)i;
> 19: if( s<r ) return -1;
> 20: if( s>r ) return +1;
> 21: return 0;
> 22: }
> 23: }
> --------------------------------------------------------
>
> Line 11: the value 9223372036854775807.0 is unrepresentable as a double.
> The compiler uses the approximation 9223372036854775808.0,
> so the condition is in fact 'if( r>9223372036854775808.0 )'.
> Line 12: when r=9223372036854775808.0 then y=SMALLEST_INT64
> and this special case is handled by the condition on line 15.
>
> But if the condition in line 11 were 'if( r>=9223372036854775808.0 )'
> then for r=9223372036854775808.0 the function would return -1
> before assigning r to y, so the condition on line 15 would be unnecessary.
>
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