A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.

llvm-svn: 160893

Catch uses of undefined physregs that haven't been added to basic block
live-in lists. Run the verifier to pinpoint the problem.

Also run the verifier when a virtual register use is not jointly
dominated by defs.

llvm-svn: 160207

These LiveRangeCalc methods are to be used when computing a live range
from scratch.

llvm-svn: 158027

Remove the same pointers from all the other LiveRangeCalc functions,
simplifying the interface.

llvm-svn: 157941

If a value is defined by a COPY, that instuction can easily and cheaply
be found by getInstructionFromIndex(VNI->def).

This reduces the size of VNInfo from 24 to 16 bytes, and improves
llc compile time by 3%.

llvm-svn: 149763

llvm-svn: 146987

Three out of four clients prefer this interface which is consistent with
extendIntervalEndTo() and LiveRangeCalc::extend().

llvm-svn: 139604

llvm-svn: 139581

SplitKit will soon need two copies of these data structures, and the
algorithms will also be useful when LiveIntervalAnalysis becomes
independent of LiveVariables.

llvm-svn: 139572