On Jan 28, 2008, at 8:29 PM, Chris Lattner wrote: > > On Jan 28, 2008, at 6:21 PM, Dale Johannesen wrote: > >> Author: johannes >> Date: Mon Jan 28 20:21:21 2008 >> New Revision: 46485 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=46485&view=rev >> Log: >> Handle 'X' constraint in asm's better. > > Hey Dale, > > Can this be done in llvm-gcc? It seems better to only expose > 'simplified' constraints to the llvm code generator. This means the > target hooks would become wonderful macros in i386.h for example, but > that seems tolerable.
Sure, but you'd have to reimplement it in clang (etc). I think it's better to have it in one place. (If you're thinking we don't need to support this in clang eventually, I don't believe it, alas.) > It also might be possible to iterate over the constraint letters > somehow in GCC, which would make it possible to implement this in a > target independent way. In llvm you mean maybe? Could be, I didn't look at that closely. I know there are some collisions between targets of machine-dependent constraint letters, but the semantics can't be too different or reload would screw up; it might be doable. That said, I'm not particularly happy with the implementation I wound up with, not neat-looking at all and there's probably cases that aren't handled the same as gcc. I don't think there's a silver bullet though. _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
