[NFC] Instruction: introduce replaceSuccessorWith() function, use it
Summary:
There is `Instruction::getNumSuccessors()`, `Instruction::getSuccessor()`
and `Instruction::setSuccessor()`, but no function to replace every
specified `BasicBlock*` successor with some other specified `BasicBlock*`.
I've found one place where it should clearly be used.
Reviewers: chandlerc, craig.topper, spatel, danielcdh
Reviewed By: craig.topper
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61010
llvm-svn: 359994
diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h
index 499c816..6a9a74b 100644
--- a/llvm/include/llvm/IR/Instruction.h
+++ b/llvm/include/llvm/IR/Instruction.h
@@ -665,6 +665,10 @@
/// instruction must be a terminator.
void setSuccessor(unsigned Idx, BasicBlock *BB);
+ /// Replace specified successor OldBB to point at the provided block.
+ /// This instruction must be a terminator.
+ void replaceSuccessorWith(BasicBlock *OldBB, BasicBlock *NewBB);
+
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static bool classof(const Value *V) {
return V->getValueID() >= Value::InstructionVal;
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index f15bd60..42a7a1c 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -675,6 +675,13 @@
llvm_unreachable("not a terminator");
}
+void Instruction::replaceSuccessorWith(BasicBlock *OldBB, BasicBlock *NewBB) {
+ for (unsigned Idx = 0, NumSuccessors = Instruction::getNumSuccessors();
+ Idx != NumSuccessors; ++Idx)
+ if (getSuccessor(Idx) == OldBB)
+ setSuccessor(Idx, NewBB);
+}
+
Instruction *Instruction::cloneImpl() const {
llvm_unreachable("Subclass of Instruction failed to implement cloneImpl");
}
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index b076e6ff..194cb5d 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -443,9 +443,7 @@
if (!LoopMD)
LoopMD = TI->getMetadata(LoopMDKind);
TI->setMetadata(LoopMDKind, nullptr);
- for (unsigned Op = 0, e = TI->getNumSuccessors(); Op != e; ++Op)
- if (TI->getSuccessor(Op) == Header)
- TI->setSuccessor(Op, BEBlock);
+ TI->replaceSuccessorWith(Header, BEBlock);
}
BEBlock->getTerminator()->setMetadata(LoopMDKind, LoopMD);