[IR] Introduce helpers to skip debug instructions (NFC)

This patch introduces two helpers to make it easier to ignore debug
intrinsics:

- Instruction::getNextNonDebugInstruction()

This is just like Instruction::getNextNode(), except that it skips debug
info.

- skipDebugInfo(BasicBlock::iterator)

A free function which advances a BasicBlock iterator past any debug
info. This is a no-op when the iterator already points to a non-debug
instruction.

Part of: llvm.org/PR37728
Related to: https://reviews.llvm.org/D47874

Differential Revision: https://reviews.llvm.org/D48305

llvm-svn: 335083

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index c103de4..005a772 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -479,3 +479,9 @@ Optional<uint64_t> BasicBlock::getIrrLoopHeaderWeight() const {
   }
   return Optional<uint64_t>();
 }
+
+BasicBlock::iterator llvm::skipDebugInfo(BasicBlock::iterator It) {
+  while (isa<DbgInfoIntrinsic>(It))
+    ++It;
+  return It;
+}