[NFC][RemoveDIs] Provide an iterator-taking split-block method

As per the stack of patches this is attached to, allow users of
BasicBlock::splitBasicBlock to provide an iterator for a position, instead
of just an instruction pointer. This is to fit with my proposal for how to
get rid of debug intrinsics [0]. There are other call-sites that would need
to change, but this is sufficient for a stage2clang self host and some
other C++ projects to build identical binaries, in the context of the whole
remove-DIs project.

[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939

Differential Revision: https://reviews.llvm.org/D152545

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
index 475b460..769a4e9 100644
--- a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
@@ -610,7 +610,7 @@ static bool unswitchTrivialBranch(Loop &L, BranchInst &BI, DominatorTree &DT,
     UnswitchedBB = LoopExitBB;
   } else {
     UnswitchedBB =
-        SplitBlock(LoopExitBB, &LoopExitBB->front(), &DT, &LI, MSSAU);
+        SplitBlock(LoopExitBB, LoopExitBB->begin(), &DT, &LI, MSSAU, "", false);
   }
 
   if (MSSAU && VerifyMemorySSA)
@@ -883,7 +883,7 @@ static bool unswitchTrivialSwitch(Loop &L, SwitchInst &SI, DominatorTree &DT,
       rewritePHINodesForUnswitchedExitBlock(*DefaultExitBB, *ParentBB, *OldPH);
     } else {
       auto *SplitBB =
-          SplitBlock(DefaultExitBB, &DefaultExitBB->front(), &DT, &LI, MSSAU);
+          SplitBlock(DefaultExitBB, DefaultExitBB->begin(), &DT, &LI, MSSAU);
       rewritePHINodesForExitAndUnswitchedBlocks(*DefaultExitBB, *SplitBB,
                                                 *ParentBB, *OldPH,
                                                 /*FullUnswitch*/ true);
@@ -910,7 +910,7 @@ static bool unswitchTrivialSwitch(Loop &L, SwitchInst &SI, DominatorTree &DT,
     BasicBlock *&SplitExitBB = SplitExitBBMap[ExitBB];
     if (!SplitExitBB) {
       // If this is the first time we see this, do the split and remember it.
-      SplitExitBB = SplitBlock(ExitBB, &ExitBB->front(), &DT, &LI, MSSAU);
+      SplitExitBB = SplitBlock(ExitBB, ExitBB->begin(), &DT, &LI, MSSAU);
       rewritePHINodesForExitAndUnswitchedBlocks(*ExitBB, *SplitExitBB,
                                                 *ParentBB, *OldPH,
                                                 /*FullUnswitch*/ true);
@@ -1211,7 +1211,7 @@ static BasicBlock *buildClonedLoopBlocks(
     // place to merge the CFG, so split the exit first. This is always safe to
     // do because there cannot be any non-loop predecessors of a loop exit in
     // loop simplified form.
-    auto *MergeBB = SplitBlock(ExitBB, &ExitBB->front(), &DT, &LI, MSSAU);
+    auto *MergeBB = SplitBlock(ExitBB, ExitBB->begin(), &DT, &LI, MSSAU);
 
     // Rearrange the names to make it easier to write test cases by having the
     // exit block carry the suffix rather than the merge block carrying the