This commit improves the `allowPatternRollback` flag handling in the
dialect conversion driver. Previously, this flag was used to merely
detect cases that are incompatible with the new One-Shot Dialect
Conversion driver. This commit implements the driver itself: when the
flag is set to "false", all IR changes are materialized immediately,
bypassing the `IRRewrite` and `ConversionValueMapping` infrastructure.
A few selected test cases now run with both the old and the new driver.
RFC:
https://discourse.llvm.org/t/rfc-a-new-one-shot-dialect-conversion-driver/79083
Also a new pass option `ConvertToLLVMPass` to populate only patterns from the specified dialects. This is needed because the existing test cases expect that only ops from certain dialects are lowered. (E.g., "arith-to-llvm" expects that only "arith" ops are lowered but not "func" ops.)
Differential Revision: https://reviews.llvm.org/D157627
This is a resubmit of the original D157391 change, which was reverted
because it needed special handling for the async dialect. (I removed it
from this change.)
Implement ConvertToLLVMPatternInterface for more dialects: arith,
complex, cf.
Differential Revision: https://reviews.llvm.org/D157391
