Specifying isSSA is an extra line at best and results in invalid MI at
worst. Compute the value instead.
Differential Revision: http://reviews.llvm.org/D22722
llvm-svn: 279600
Change the syntax to use `%0.sub8` to denote a subregister.
This seems like a more natural fit to denote subregisters; I also plan
to introduce a new ":classname" syntax in upcoming patches to denote the
register class of a vreg.
Note that this commit disallows plain identifiers to start with a '.'
character. This shouldn't affect anything as external names/IR
references are all prefixed with '$'/'%', plain identifiers are only
used for instruction names, register mask names and subreg indexes.
Differential Revision: https://reviews.llvm.org/D22390
llvm-svn: 276815
Currently the MIR framework prints all its outputs (errors and actual
representation) on stderr.
This patch fixes that by printing the regular output in the output
specified with -o.
Differential Revision: http://reviews.llvm.org/D22251
llvm-svn: 275314
In case of COPY-like instruction we may be able to deduce that a certain
input is unused, based on the used lanes of the register defined by the
instruction.
This even works accross otherwise incompatible copies (no need to have
compatible lanemasks, completely unused operands are still completely
unused). It even makes sense to redo the analysis in this case since we
gained information for a case we previously stopped at because of the
incompatible masks.
llvm-svn: 268815
The DetectDeadLanes pass performs a dataflow analysis of used/defined
subregister lanes across COPY instructions and instructions that will
get lowered to copies. It detects dead definitions and uses reading
undefined values which are obscured by COPY and subregister usage.
These dead definitions cause trouble in the register coalescer which
cannot deal with definitions suddenly becoming dead after coalescing
COPY instructions.
For now the pass only adds dead and undef flags to machine operands. It
should be possible to extend it in the future to remove the dead
instructions and redo the analysis for the affected virtual
registers.
Differential Revision: http://reviews.llvm.org/D18427
llvm-svn: 267851
Matthias Braun