http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55457
Bug #: 55457
Summary: Having some predefined macros to get more information
about gcc vector extensions capabilities would be nice
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: siarhei.siamas...@gmail.com
One practical problem is how to identify whether vector extensions are
beneficial or a fallback to the standard C code is better to be taken. In the
case of OpenCL, there are param values such as
CL_DEVICE_PREFERRED_VECTOR_WIDTH_INT, CL_DEVICE_PREFERRED_VECTOR_WIDTH_FLOAT,
etc.
http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/clGetDeviceInfo.html
If gcc could have some sort of predefined macro telling that "preferred vector
width is 1", it could be used in the code to avoid getting performance penalty
by just using normal C code when compiling for non-SIMD capable platforms.
