From 523c656e254769c455c5519739cf097dcd2260c7 Mon Sep 17 00:00:00 2001 From: Matt Davis Date: Fri, 23 Feb 2018 17:38:27 +0000 Subject: [Debug] Add dbg.value intrinsics for PHIs created during LCSSA. Summary: This patch is an enhancement to propagate dbg.value information when Phis are created on behalf of LCSSA. I noticed a case where a value carried across a loop was reported as . Specifically this case: ``` int bar(int x, int y) { return x + y; } int foo(int size) { int val = 0; for (int i = 0; i < size; ++i) { val = bar(val, i); // Both val and i are correct } return val; // } ``` In the above case, after all of the interesting computation completes our value is reported as "optimized out." This change will add a dbg.value to correct this. This patch also moves the dbg.value insertion routine from LoopRotation.cpp into Local.cpp, so that we can share it in both places (LoopRotation and LCSSA). Reviewers: mzolotukhin, aprantl, vsk, davide Reviewed By: aprantl, vsk Subscribers: dberlin, llvm-commits Differential Revision: https://reviews.llvm.org/D42551 llvm-svn: 325926 --- llvm/lib/Transforms/Utils/Local.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'llvm/lib/Transforms/Utils/Local.cpp') diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 7573fc3..fa059a1 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -1365,14 +1365,17 @@ void llvm::insertDebugValuesForPHIs(BasicBlock *BB, // propagate the info through the new PHI. LLVMContext &C = BB->getContext(); for (auto PHI : InsertedPHIs) { + BasicBlock *Parent = PHI->getParent(); + // Avoid inserting an intrinsic into an EH block. + if (Parent->getFirstNonPHI()->isEHPad()) + continue; + auto PhiMAV = MetadataAsValue::get(C, ValueAsMetadata::get(PHI)); for (auto VI : PHI->operand_values()) { auto V = DbgValueMap.find(VI); if (V != DbgValueMap.end()) { auto *DbgII = cast(V->second); Instruction *NewDbgII = DbgII->clone(); - auto PhiMAV = MetadataAsValue::get(C, ValueAsMetadata::get(PHI)); NewDbgII->setOperand(0, PhiMAV); - BasicBlock *Parent = PHI->getParent(); auto InsertionPt = Parent->getFirstInsertionPt(); assert(InsertionPt != Parent->end() && "Ill-formed basic block"); NewDbgII->insertBefore(&*InsertionPt); -- cgit v1.1