diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/Local.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/Local.cpp | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 1153f3cbd15..82fb765842d 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -2529,6 +2529,47 @@ void llvm::dropDebugUsers(Instruction &I) { DII->eraseFromParent(); } +void llvm::hoistAllInstructionsInto(BasicBlock *DomBlock, Instruction *InsertPt, + BasicBlock *BB) { + // Since we are moving the instructions out of its basic block, we do not + // retain their original debug locations (DILocations) and debug intrinsic + // instructions (dbg.values). + // + // Doing so would degrade the debugging experience and adversely affect the + // accuracy of profiling information. + // + // Currently, when hoisting the instructions, we take the following actions: + // - Remove their dbg.values. + // - Set their debug locations to the values from the insertion point. + // + // As per PR39141 (comment #8), the more fundamental reason why the dbg.values + // need to be deleted, is because there will not be any instructions with a + // DILocation in either branch left after performing the transformation. We + // can only insert a dbg.value after the two branches are joined again. + // + // See PR38762, PR39243 for more details. + // + // TODO: Extend llvm.dbg.value to take more than one SSA Value (PR39141) to + // encode predicated DIExpressions that yield different results on different + // code paths. + for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE;) { + Instruction *I = &*II; + I->dropUnknownNonDebugMetadata(); + if (I->isUsedByMetadata()) + dropDebugUsers(*I); + if (isa<DbgVariableIntrinsic>(I)) { + // Remove DbgInfo Intrinsics. + II = I->eraseFromParent(); + continue; + } + I->setDebugLoc(InsertPt->getDebugLoc()); + ++II; + } + DomBlock->getInstList().splice(InsertPt->getIterator(), BB->getInstList(), + BB->begin(), + BB->getTerminator()->getIterator()); +} + namespace { /// A potential constituent of a bitreverse or bswap expression. See |
