Index: lib/Transforms/Scalar/GVNHoist.cpp =================================================================== --- lib/Transforms/Scalar/GVNHoist.cpp +++ lib/Transforms/Scalar/GVNHoist.cpp @@ -795,8 +795,8 @@ for (auto IDFB : IDFBlocks) { // TODO: Prune out useless CHI insertions. for (unsigned i = 0; i < V.size(); ++i) { CHIArg C = {VN, nullptr, nullptr}; - if (DT->dominates(IDFB, V[i]->getParent())) { // Ignore spurious PDFs. - // InValue[V[i]->getParent()].push_back(std::make_pair(VN, V[i])); + // Ignore spurious PDFs. + if (DT->properlyDominates(IDFB, V[i]->getParent())) { OutValue[IDFB].push_back(C); DEBUG(dbgs() << "\nInsertion a CHI for BB: " << IDFB->getName() << ", for Insn: " << *V[i]); Index: test/Transforms/GVNHoist/pr35222-hoist-load.ll =================================================================== --- /dev/null +++ test/Transforms/GVNHoist/pr35222-hoist-load.ll @@ -0,0 +1,25 @@ +; RUN: opt -S -gvn-hoist < %s | FileCheck %s +; CHECK: load +; CHECK: load +; Check that the load is not hoisted because the call can potentially +; modify the global + +target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64" + +@heap = external global i32, align 4 + +define i32 @build_tree() unnamed_addr { +entry: + br label %do.body + +do.body: ; preds = %do.body, %entry + %tmp9 = load i32, i32* @heap, align 4 + %cmp = call i1 @pqdownheap(i32 %tmp9) + br i1 %cmp, label %do.body, label %do.end + +do.end: ; preds = %do.body + %tmp20 = load i32, i32* @heap, align 4 + ret i32 %tmp20 +} + +declare i1 @pqdownheap(i32)