[PATCH] D19061: [ARM] Add support for the X asm constraint

[silviu.baranga@arm.com via llvm-commits]

sbaranga added a comment.

Thanks, James!

The current implementation will only perform the lowering part (and force this to a register by converting to "r" or "w") if the operand is not a basic block, function, or integer constant - so this should cover some of those use cases.

It is true that GCC would be more efficient in some cases (one example would be FP constants), but we would still fit into the definition of "no constraint whatsoever" and therefore correct - which is an improvement from the current situation, where we'll simply crash on this constraint.

We can still improve our handling of this constraint, but that would be something that is target independent and outside the scope of this patch.

Thanks,
Silviu


http://reviews.llvm.org/D19061