Comment Re:outperform "c" (Score 1) 745
FORTRAN has different aliasing rules than C. If you
have
subroutine foo(x,y)
double x(10), y(10)
FORTRAN assumes that x and y refer to distinct arrays (i.e., you can't modify an element of y with an assignment to an element of x).
If you have
void foo(double x[10], double y[10])
C assumes that x and y can overlap (i.e., modifying an element of x can change an element of y).
Language differences such as this one allow FORTRAN compilers to do a better job. With the introduction of the restrict keyword in C99, C compilers have a chance to match FORTRAN performance.
have
subroutine foo(x,y)
double x(10), y(10)
FORTRAN assumes that x and y refer to distinct arrays (i.e., you can't modify an element of y with an assignment to an element of x).
If you have
void foo(double x[10], double y[10])
C assumes that x and y can overlap (i.e., modifying an element of x can change an element of y).
Language differences such as this one allow FORTRAN compilers to do a better job. With the introduction of the restrict keyword in C99, C compilers have a chance to match FORTRAN performance.
