This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: ssa bootstrap problem on x86 (cmpstrsi_1 pattern)
>>>>> "Joern" == Joern Rennecke <amylaar@cygnus.co.uk> writes:
>> The only reason clobbers appear this early in the compiler is
>> that GCC generates machine-specific code very early. There is
>> no operation
Joern> That is not true. When gcc synthesizes a move that is
Joern> wider than the widest one available in the machine
Joern> description, it first clobbers the destination, then does a
Joern> series of moves into SUBREGs of the destination.
But, again, isn't that a machine-specific issue? These moves could be
represented directly as a SET and then resolved to an operation
involving SUBREGs and CLOBBERs later.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com