The answer is: it's a gcc bug. The attached program should print
x = 12.3
y = 12.3
but if compiled with -O or -O2 on Stefan's machine, I get garbage:
$ gcc -O ftest.c
$ ./a.out
x = 12.3
y = 1.47203e-39
$ gcc -v
Reading specs from /usr/lib/gcc-lib/sparc64-unknown-openbsd3.6/3.3.2/specs
Configured with:
Thread model: single
gcc version 3.3.2 (propolice)
$
regards, tom lane
#include <stdio.h>
float
returnfloat(float *x)
{
return *x;
}
int
main()
{
float x = 12.3;
union {
float f;
char *t;
} y;
y.f = returnfloat(&x);
printf("x = %g\n", x);
printf("y = %g\n", y.f);
return 0;
}
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