This way of using getNextOperandForReg() was unlikely to work as
intended. We don't give any guarantees about the order of operands in
the use-def chains, so looking only at operands following a given
operand in the chain doesn't make sense.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161542 91177308-0d34-0410-b5e6-96231b3b80d8
This cleans up the method used to find trip counts in order to form CTR loops on PPC.
This refactoring allows the pass to find loops which have a constant trip count but also
happen to end with a comparison to zero. This also adds explicit FIXMEs to mark two different
classes of loops that are currently ignored.
In addition, we now search through all potential induction operations instead of just the first.
Also, we check the predicate code on the conditional branch and abort the transformation if the
code is not EQ or NE, and we then make sure that the branch to be transformed matches the
condition register defined by the comparison (multiple possible comparisons will be considered).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158607 91177308-0d34-0410-b5e6-96231b3b80d8
The code which tests for an induction operation cannot assume that any
ADDI instruction will have a register operand because the operand could
also be a frame index; for example:
%vreg16<def> = ADDI8 <fi#0>, 0; G8RC:%vreg16
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158205 91177308-0d34-0410-b5e6-96231b3b80d8
This pass is derived from the Hexagon HardwareLoops pass. The only significant enhancement over the Hexagon
pass is that PPCCTRLoops will also attempt to delete the replaced add and compare operations if they are
no longer otherwise used. Also, invalid preheader DebugLoc is not used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158204 91177308-0d34-0410-b5e6-96231b3b80d8
