[llvm] [X86, SimplifyCFG] Support hoisting load/store with conditional faulting (Part II) (PR #108812)

[Shengchen Kan via llvm-commits]

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@@ -1663,18 +1663,29 @@ static bool areIdenticalUpToCommutativity(const Instruction *I1,
 static void hoistConditionalLoadsStores(
     BranchInst *BI,
     SmallVectorImpl<Instruction *> &SpeculatedConditionalLoadsStores,
-    bool Invert) {
+    std::optional<bool> Invert) {
   auto &Context = BI->getParent()->getContext();
   auto *VCondTy = FixedVectorType::get(Type::getInt1Ty(Context), 1);
   auto *Cond = BI->getOperand(0);
   // Construct the condition if needed.
   BasicBlock *BB = BI->getParent();
-  IRBuilder<> Builder(SpeculatedConditionalLoadsStores.back());
-  Value *Mask = Builder.CreateBitCast(
-      Invert ? Builder.CreateXor(Cond, ConstantInt::getTrue(Context)) : Cond,
-      VCondTy);
+  IRBuilder<> Builder(Invert ? SpeculatedConditionalLoadsStores.back() : BI);
+  Value *Mask = nullptr;
+  Value *Mask0 = nullptr;
+  Value *Mask1 = nullptr;
+  if (Invert) {
+    Mask = Builder.CreateBitCast(
+        *Invert ? Builder.CreateXor(Cond, ConstantInt::getTrue(Context)) : Cond,
+        VCondTy);
+  } else {
+    Mask0 = Builder.CreateBitCast(
+        Builder.CreateXor(Cond, ConstantInt::getTrue(Context)), VCondTy);
+    Mask1 = Builder.CreateBitCast(Cond, VCondTy);
+  }
   for (auto *I : SpeculatedConditionalLoadsStores) {
-    IRBuilder<> Builder(I);
+    IRBuilder<> Builder(Invert ? I : BI);
+    if (!Invert)
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KanRobert wrote:

`if (!Mask)`  looks better?

https://github.com/llvm/llvm-project/pull/108812