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Patch for Re: out of date docs? (alpha/64bit vs. 32bit vs. cross)
- From: Gerald Pfeifer <gerald at pfeifer dot com>
- To: Ian Lance Taylor <iant at google dot com>, Rainer Orth <ro at TechFak dot Uni-Bielefeld dot DE>
- Cc: Jay <jay dot krell at cornell dot edu>, gcc at gcc dot gnu dot org
- Date: Sun, 2 Nov 2008 21:19:25 +0100 (CET)
- Subject: Patch for Re: out of date docs? (alpha/64bit vs. 32bit vs. cross)
- References: <COL101-W65504D1937E5287C54170E62C0@phx.gbl> <m3abcz84cr.fsf@google.com>
On Mon, 20 Oct 2008, Ian Lance Taylor wrote:
>> http://gcc.gnu.org/install/specific.html#alpha-dec-osf
>>
>> "Note that since the Alpha is a 64-bit architecture, cross-compilers from 32-bit machines will not generate code as efficient as that generated when the compiler is running on a 64-bit machine because many optimizations that depend on being able to represent a word on the target in an integral value on the host cannot be performed. Building cross-compilers on the Alpha for 32-bit machines has only been tested in a few cases and may not work properly. "
>>
>> This is false lately, eh?
>> Can it be amended to note what versions it was possibly true for and what versions it is definitely false for?
>> In particular, I /assume/ it is false for any version that uses gmp.
> I believe that this is false these days. I believe that it has been
> false since a cross-compiler to the alpha required a 64-bit
> HOST_WIDE_INT, which was in gcc 3.4.
Does this mean you (or Rainer) would approve the following documentation
update? ;-)
Gerald
2008-11-02 Gerald Pfeifer <gerald@pfeifer.com>
* doc/install.texi (alpha*-dec-osf*): Remove note on 32-bit
hosted cross-compilers generating less efficient code.
Index: doc/install.texi
===================================================================
--- doc/install.texi (revision 141527)
+++ doc/install.texi (working copy)
@@ -2746,14 +2746,6 @@
new version of DEC Unix, you should rebuild GCC to pick up the new version
stamp.
-Note that since the Alpha is a 64-bit architecture, cross-compilers from
-32-bit machines will not generate code as efficient as that generated
-when the compiler is running on a 64-bit machine because many
-optimizations that depend on being able to represent a word on the
-target in an integral value on the host cannot be performed. Building
-cross-compilers on the Alpha for 32-bit machines has only been tested in
-a few cases and may not work properly.
-
@samp{make compare} may fail on old versions of DEC Unix unless you add
@option{-save-temps} to @code{BOOT_CFLAGS}. On these systems, the name
of the assembler input file is stored in the object file, and that makes