X32 project status update

From: H.J. Lu
Date: Sat May 21 2011 - 11:02:23 EST


Hi,

This is the x32 project status update:

https://sites.google.com/site/x32abi/

With the latest x32 kernel semctl bug fix, C, C++ and Fortran
test results on GCC x32 branch only show one serious bug:

FAIL: gcc.c-torture/execute/builtins/strcspn.c execution, -O1

It is due to the combine issue:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49088

I am planning to prepare merging GCC x32 branch with trunk
followed by glibc and gdb patches.

The current x32 implementation uses DImode for Pmode.
I chose it because:

1. x32 process is running in 64bit mode. Hardware pointer
in x32 is 64bit.
2. x86 backend maps Pmode to hardware pointer mode.
Use SImode for Pmode requires extra changes in x86 bakend.
3. 32bit base/index are supported in x32 when they are
generated by middle-end via ptr_mode which is 32bit.

But I'd like to keep the option open to switch Pmode to
SImode later if it can provide better performance and/or
reduce the code size.

GCC x32 branch is available at:

svn://gcc.gnu.org/svn/gcc/branches/x32

Majority of changes are in x86 backend and there are also
some middle-end changes. I appreciate any feedbacks.

Thanks.

--
H.J.
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