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Re: [csl-sol210] Patch to disable ldd and std for 32-bit SPARC
- From: Richard Henderson <rth at redhat dot com>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 19 May 2005 17:10:16 -0700
- Subject: Re: [csl-sol210] Patch to disable ldd and std for 32-bit SPARC
- References: <Pine.LNX.email@example.com>
On Thu, May 19, 2005 at 10:09:24PM +0000, Joseph S. Myers wrote:
> This patch, for csl-sol210-3_4-branch (which is now being used more
> generally for the Solaris 10 compiler on SPARC as well as AMD64), adds
> a command-line option to disable use of the SPARC ldd and std
> instructions with integer operands. This is for use with large bodies
> of legacy code which has inadequately aligned 64-bit values.
I think the option is mis-named and specifies the wrong thing.
It should instead specify that long long implies only 32-bit
If the compiler can prove (or generate for itself) larger alignment,
then it should still be allowed to use ldd/std.
Further, by not properly telling the optimizers about the real
alignment, you risk emitting wrong-code for some corner cases.