Add splitCriticalEdgesFrom API.

Author: atrick

include/swift/SILOptimizer/Utils/CFG.h

@@ -76,6 +76,10 @@ SILBasicBlock *splitIfCriticalEdge(SILBasicBlock *From, SILBasicBlock *To,
                                    DominanceInfo *DT = nullptr,
                                    SILLoopInfo *LI = nullptr);
 
+/// Splits all critical edges originating from `fromBB`.
+bool splitCriticalEdgesFrom(SILBasicBlock *fromBB, DominanceInfo *DT = nullptr,
+                            SILLoopInfo *LI = nullptr);
+
 /// \brief Splits the edges between two basic blocks.
 ///
 /// Updates dominance information and loop information if not null.

lib/SILOptimizer/Utils/CFG.cpp

@@ -411,6 +411,16 @@ SILBasicBlock *swift::splitCriticalEdge(TermInst *T, unsigned EdgeIdx,
   return splitEdge(T, EdgeIdx, DT, LI);
 }
 
+bool swift::splitCriticalEdgesFrom(SILBasicBlock *fromBB, DominanceInfo *DT,
+                                   SILLoopInfo *LI) {
+  bool Changed = false;
+  for (unsigned idx = 0, e = fromBB->getSuccessors().size(); idx != e; ++idx) {
+    auto *NewBB = splitCriticalEdge(fromBB->getTerminator(), idx, DT, LI);
+    Changed |= (NewBB != nullptr);
+  }
+  return Changed;
+}
+
 bool swift::hasCriticalEdges(SILFunction &F, bool OnlyNonCondBr) {
   for (SILBasicBlock &BB : F) {
     // Only consider critical edges for terminators that don't support block