3 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
4c82a9e7d0 Detect and handle COPY in many places.
This code is transitional, it will soon be possible to eliminate
isExtractSubreg, isInsertSubreg, and isMoveInstr in most places.

llvm-svn: 107547
2010-07-03 00:04:37 +00:00
Bob Wilson
01abf8fc2f Besides removing phi cycles that reduce to a single value, also remove dead
phi cycles.  Adjust a few tests to keep dead instructions from being optimized
away.  This (together with my previous change for phi cycles) fixes Apple
radar 7627077.

llvm-svn: 96057
2010-02-13 00:31:44 +00:00
Bob Wilson
0827e040e0 Add a new pass on machine instructions to optimize away PHI cycles that
reduce down to a single value.  InstCombine already does this transformation
but DAG legalization may introduce new opportunities.  This has turned out to
be important for ARM where 64-bit values are split up during type legalization:
InstCombine is not able to remove the PHI cycles on the 64-bit values but
the separate 32-bit values can be optimized.  I measured the compile time 
impact of this (running llc on 176.gcc) and it was not significant.

llvm-svn: 95951
2010-02-12 01:30:21 +00:00