Phase 1 of refactoring the MachineRegisterInfo iterators to make them suitable

for use with C++11 range-based for-loops.

The gist of phase 1 is to remove the skipInstruction() and skipBundle()
methods from these iterators, instead splitting each iterator into a version
that walks operands, a version that walks instructions, and a version that
walks bundles.  This has the result of making some "clever" loops in lib/CodeGen
more verbose, but also makes their iterator invalidation characteristics much
more obvious to the casual reader. (Making them concise again in the future is a
good motivating case for a pre-incrementing range adapter!)

Phase 2 of this undertaking with consist of removing the getOperand() method,
and changing operator*() of the operand-walker to return a MachineOperand&.  At
that point, it should be possible to add range views for them that work as one
might expect.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203757 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index 64e6da51e4..13ea1a58e0 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -939,8 +939,11 @@ void RegisterCoalescer::updateRegDefsUses(unsigned SrcReg,
   LiveInterval *DstInt = DstIsPhys ? 0 : &LIS->getInterval(DstReg);
 
   SmallPtrSet<MachineInstr*, 8> Visited;
-  for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(SrcReg);
-       MachineInstr *UseMI = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       I = MRI->reg_instr_begin(SrcReg), E = MRI->reg_instr_end();
+       I != E; ) {
+    MachineInstr *UseMI = &*(I++);
+
     // Each instruction can only be rewritten once because sub-register
     // composition is not always idempotent. When SrcReg != DstReg, rewriting
     // the UseMI operands removes them from the SrcReg use-def chain, but when