Bug 85321

Description of problem:
//////////main.c
extern double rightfunc(double);
extern double wrongfunc(double);
int
main(void)
{
  if (rightfunc(0.75) != 0.75)
    return 1;
  const double x = 0.25;
  if (wrongfunc(x) != 0.25)
    return 2;
  return 0;
}

//////////funcs.c
extern double rightfunc(double);
extern double wrongfunc(double);
double rightfunc(double t) { return t; }
double wrongfunc(const double t) { return t; }

//////////GNUmakefile:
all: right wrong
right: main.c funcs.c; gcc -O3 -o $@ main.c funcs.c
wrong: main.c funcs.c; gcc -O3 -ffloat-store -o $@ main.c funcs.c

With the three supplied files, use gmake to build.

The generated 'right' file works properly, but the
generated 'wrong' file generates incorrect code
for the 'wrongfunc' function:

wrongfunc:
        pushl   %ebp
        movl    %esp, %ebp
        subl    $8, %esp
        fldl    -8(%ebp)
        leave
        ret

Basically, the code uses memory that has not be set
to the value passed as the 'const double' argument.

Note that rightfunc() has a double argument, while
wrongfunc() has a const double argument.  Otherwise
they are the same.

The 'wrong' file is built with -ffloat-store while
the 'right' file is built without.


Version-Release number of selected component (if applicable):

gcc version 2.96 20000731 (Red Hat Linux 7.2 2.96-112.7.2)

How reproducible:
Always

Steps to Reproduce:
1. Create specified main.c, funcs.c, and GNUmakefile
2. gmake
3. ./wrong


Actual Results:  ./wrong exits with 2.


Expected Results:  ./wrong should exit with 0 (like ./right).


Additional info:

This bug occurs when using -ffloat-store with
gcc version 2.96 20000731 (Red Hat Linux 7.2 2.96-112.7.2),
with or without optimization.

It does not occur with gcc 2.91 or gcc 3.2.2.