diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/TypePromotion.cpp | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/TypePromotion.cpp b/llvm/lib/CodeGen/TypePromotion.cpp index d78589c4a05..000cd366dd6 100644 --- a/llvm/lib/CodeGen/TypePromotion.cpp +++ b/llvm/lib/CodeGen/TypePromotion.cpp @@ -46,7 +46,7 @@ using namespace llvm; static cl::opt<bool> -DisablePromotion("disable-type-promotion", cl::Hidden, cl::init(true), +DisablePromotion("disable-type-promotion", cl::Hidden, cl::init(false), cl::desc("Disable type promotion pass")); // The goal of this pass is to enable more efficient code generation for @@ -902,16 +902,34 @@ bool TypePromotion::TryToPromote(Value *V, unsigned PromotedWidth) { for (auto *I : CurrentVisited) I->dump(); ); + + // Check that promoting this at the IR level is most likely beneficial. It's + // more likely if we're operating over multiple blocks and handling wrapping + // instructions. unsigned ToPromote = 0; + unsigned NonFreeArgs = 0; + SmallPtrSet<BasicBlock*, 4> Blocks; for (auto *V : CurrentVisited) { - if (Sources.count(V)) + if (auto *I = dyn_cast<Instruction>(V)) + Blocks.insert(I->getParent()); + + if (Sources.count(V)) { + if (auto *Arg = dyn_cast<Argument>(V)) { + if (!Arg->hasZExtAttr() && !Arg->hasSExtAttr()) + ++NonFreeArgs; + } continue; + } + if (Sinks.count(cast<Instruction>(V))) continue; + ++ToPromote; } - if (ToPromote < 2) + // DAG optimisations should be able to handle these cases better, especially + // for function arguments. + if (ToPromote < 2 || (Blocks.size() == 1 && (NonFreeArgs > SafeWrap.size()))) return false; Promoter->Mutate(OrigTy, PromotedWidth, CurrentVisited, Sources, Sinks, |
