In computeRegisterLiveness, the max instructions to search
was counting dbg_value instructions, which could potentially
cause an observable codegen change from the presence of debug
info.
llvm-svn: 341028
If there is an unused def, this would previously
report that the register was live. Check for uses
first so that it is reported as dead if never used.
llvm-svn: 341027
If the end of the block is reached during the scan, check
the live ins of the successors. This was already done in the
other direction if the block entry was reached.
llvm-svn: 341026
This needs to be done in the SSA fold operands
pass to be effective, so there is a bit of overlap
with SIShrinkInstructions but I don't think this
is practically avoidable.
llvm-svn: 340859