Move widenable branch formation into makeGuardControlFlowExplicit helper

This is mostly NFC, but I removed the setting of the guard's calling convention onto the WC call.  Why?  Because it was untested, and was producing an ill defined output as the declaration's convention wasn't been changed leaving a mismatch which is UB.

3 files changed, 16 insertions, 17 deletions

diff --git a/llvm/lib/Transforms/Scalar/LowerGuardIntrinsic.cpp b/llvm/lib/Transforms/Scalar/LowerGuardIntrinsic.cpp
index f8aa2802cce..45f5929e3b9 100644
--- a/llvm/lib/Transforms/Scalar/LowerGuardIntrinsic.cpp
+++ b/llvm/lib/Transforms/Scalar/LowerGuardIntrinsic.cpp
@@ -61,7 +61,7 @@ static bool lowerGuardIntrinsic(Function &F) {
   DeoptIntrinsic->setCallingConv(GuardDecl->getCallingConv());
 
   for (auto *CI : ToLower) {
-    makeGuardControlFlowExplicit(DeoptIntrinsic, CI);
+    makeGuardControlFlowExplicit(DeoptIntrinsic, CI, false);
     CI->eraseFromParent();
   }
 
diff --git a/llvm/lib/Transforms/Scalar/MakeGuardsExplicit.cpp b/llvm/lib/Transforms/Scalar/MakeGuardsExplicit.cpp
index fd8a3643cff..0e3fcf0eb77 100644
--- a/llvm/lib/Transforms/Scalar/MakeGuardsExplicit.cpp
+++ b/llvm/lib/Transforms/Scalar/MakeGuardsExplicit.cpp
@@ -58,22 +58,9 @@ struct MakeGuardsExplicitLegacyPass : public FunctionPass {
 static void turnToExplicitForm(CallInst *Guard, Function *DeoptIntrinsic) {
   // Replace the guard with an explicit branch (just like in GuardWidening).
   BasicBlock *BB = Guard->getParent();
-  makeGuardControlFlowExplicit(DeoptIntrinsic, Guard);
-  BranchInst *ExplicitGuard = cast<BranchInst>(BB->getTerminator());
-  assert(ExplicitGuard->isConditional() && "Must be!");
+  makeGuardControlFlowExplicit(DeoptIntrinsic, Guard, true);
+  assert(isWidenableBranch(BB->getTerminator()) && "should hold");
 
-  // We want the guard to be expressed as explicit control flow, but still be
-  // widenable. For that, we add Widenable Condition intrinsic call to the
-  // guard's condition.
-  IRBuilder<> B(ExplicitGuard);
-  auto *WidenableCondition =
-      B.CreateIntrinsic(Intrinsic::experimental_widenable_condition,
-                        {}, {}, nullptr, "widenable_cond");
-  WidenableCondition->setCallingConv(Guard->getCallingConv());
-  auto *NewCond =
-      B.CreateAnd(ExplicitGuard->getCondition(), WidenableCondition);
-  NewCond->setName("exiplicit_guard_cond");
-  ExplicitGuard->setCondition(NewCond);
   Guard->eraseFromParent();
 }
 
diff --git a/llvm/lib/Transforms/Utils/GuardUtils.cpp b/llvm/lib/Transforms/Utils/GuardUtils.cpp
index 37fca0d129b..b8c4c764e74 100644
--- a/llvm/lib/Transforms/Utils/GuardUtils.cpp
+++ b/llvm/lib/Transforms/Utils/GuardUtils.cpp
@@ -26,7 +26,7 @@ static cl::opt<uint32_t> PredicatePassBranchWeight(
              "reciprocal of this value (default = 1 << 20)"));
 
 void llvm::makeGuardControlFlowExplicit(Function *DeoptIntrinsic,
-                                        CallInst *Guard) {
+                                        CallInst *Guard, bool UseWC) {
   OperandBundleDef DeoptOB(*Guard->getOperandBundle(LLVMContext::OB_deopt));
   SmallVector<Value *, 4> Args(std::next(Guard->arg_begin()), Guard->arg_end());
 
@@ -62,6 +62,18 @@ void llvm::makeGuardControlFlowExplicit(Function *DeoptIntrinsic,
 
   DeoptCall->setCallingConv(Guard->getCallingConv());
   DeoptBlockTerm->eraseFromParent();
+
+  if (UseWC) {
+    // We want the guard to be expressed as explicit control flow, but still be
+    // widenable. For that, we add Widenable Condition intrinsic call to the
+    // guard's condition.
+    IRBuilder<> B(CheckBI);
+    auto *WC = B.CreateIntrinsic(Intrinsic::experimental_widenable_condition,
+                                 {}, {}, nullptr, "widenable_cond");
+    CheckBI->setCondition(B.CreateAnd(CheckBI->getCondition(), WC,
+                                      "exiplicit_guard_cond"));
+    assert(isWidenableBranch(CheckBI) && "sanity check");
+  }
 }