On architectures that support IEEE 754 float representation, a common trick to
quickly cast an unsigned long val to a float in the range [0, 1) is the
following:
unsigned long temp = (val & 0x07fffff) | 0x3f800000;
return *((float *)&temp) - 1.0f;
With gcc 4.0.1 using -O2 optimization this trick no longer seems to work.
--
Summary: unsigned long to float conversion by casting unsigned
long* to float* fails in -O2 builds.
Product: gcc
Version: 4.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gino at dtecta dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23421
