diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp index e951d98c0c8..37b97830716 100644 --- a/lib/Transforms/Scalar/CodeGenPrepare.cpp +++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp @@ -594,15 +594,12 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) { return false; Value *V = RI->getReturnValue(); - if (!V) - return false; - - PHINode *PN = dyn_cast(V); - if (!PN) + PHINode *PN = V ? dyn_cast(V) : NULL; + if (V && !PN) return false; BasicBlock *BB = RI->getParent(); - if (PN->getParent() != BB) + if (PN && PN->getParent() != BB) return false; // It's not safe to eliminate the sign / zero extension of the return value. @@ -612,21 +609,44 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) { if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt)) return false; - // Make sure there are no instructions between PHI and return. - BasicBlock::iterator BI = PN; - do { ++BI; } while (isa(BI)); - if (&*BI != RI) - return false; + // Make sure there are no instructions between the PHI and return, or that the + // return is the first instruction in the block. + if (PN) { + BasicBlock::iterator BI = BB->begin(); + do { ++BI; } while (isa(BI)); + if (&*BI != RI) + return false; + } else { + if (&*BB->begin() != RI) + return false; + } /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail /// call. SmallVector TailCalls; - for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) { - CallInst *CI = dyn_cast(PN->getIncomingValue(I)); - // Make sure the phi value is indeed produced by the tail call. - if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) && - TLI->mayBeEmittedAsTailCall(CI)) - TailCalls.push_back(CI); + if (PN) { + for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) { + CallInst *CI = dyn_cast(PN->getIncomingValue(I)); + // Make sure the phi value is indeed produced by the tail call. + if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) && + TLI->mayBeEmittedAsTailCall(CI)) + TailCalls.push_back(CI); + } + } else { + SmallPtrSet VisitedBBs; + for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) { + if (!VisitedBBs.insert(*PI)) + continue; + + BasicBlock::InstListType &InstList = (*PI)->getInstList(); + BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin(); + BasicBlock::InstListType::reverse_iterator RE = InstList.rend(); + if (++RI == RE) + continue; + CallInst *CI = dyn_cast(&*RI); + if (CI && CI->getType()->isVoidTy() && TLI->mayBeEmittedAsTailCall(CI)) + TailCalls.push_back(CI); + } } bool Changed = false; diff --git a/test/CodeGen/X86/tailcall-returndup-void.ll b/test/CodeGen/X86/tailcall-returndup-void.ll new file mode 100644 index 00000000000..c1d631225ec --- /dev/null +++ b/test/CodeGen/X86/tailcall-returndup-void.ll @@ -0,0 +1,37 @@ +; RUN: llc < %s -march=x86-64 | FileCheck %s +; CHECK: rBM_info +; CHECK-NOT: ret + +@sES_closure = external global [0 x i64] +declare cc10 void @sEH_info(i64* noalias nocapture, i64* noalias nocapture, i64* noalias nocapture, i64, i64, i64) align 8 + +define cc10 void @rBM_info(i64* noalias nocapture %Base_Arg, i64* noalias nocapture %Sp_Arg, i64* noalias nocapture %Hp_Arg, i64 %R1_Arg, i64 %R2_Arg, i64 %R3_Arg) nounwind align 8 { +c263: + %ln265 = getelementptr inbounds i64* %Sp_Arg, i64 -2 + %ln266 = ptrtoint i64* %ln265 to i64 + %ln268 = icmp ult i64 %ln266, %R3_Arg + br i1 %ln268, label %c26a, label %n26p + +n26p: ; preds = %c263 + br i1 icmp ne (i64 and (i64 ptrtoint ([0 x i64]* @sES_closure to i64), i64 7), i64 0), label %c1ZP.i, label %n1ZQ.i + +n1ZQ.i: ; preds = %n26p + %ln1ZT.i = load i64* getelementptr inbounds ([0 x i64]* @sES_closure, i64 0, i64 0), align 8 + %ln1ZU.i = inttoptr i64 %ln1ZT.i to void (i64*, i64*, i64*, i64, i64, i64)* + tail call cc10 void %ln1ZU.i(i64* %Base_Arg, i64* %Sp_Arg, i64* %Hp_Arg, i64 ptrtoint ([0 x i64]* @sES_closure to i64), i64 ptrtoint ([0 x i64]* @sES_closure to i64), i64 %R3_Arg) nounwind + br label %rBL_info.exit + +c1ZP.i: ; preds = %n26p + tail call cc10 void @sEH_info(i64* %Base_Arg, i64* %Sp_Arg, i64* %Hp_Arg, i64 ptrtoint ([0 x i64]* @sES_closure to i64), i64 ptrtoint ([0 x i64]* @sES_closure to i64), i64 %R3_Arg) nounwind + br label %rBL_info.exit + +rBL_info.exit: ; preds = %c1ZP.i, %n1ZQ.i + ret void + +c26a: ; preds = %c263 + %ln27h = getelementptr inbounds i64* %Base_Arg, i64 -2 + %ln27j = load i64* %ln27h, align 8 + %ln27k = inttoptr i64 %ln27j to void (i64*, i64*, i64*, i64, i64, i64)* + tail call cc10 void %ln27k(i64* %Base_Arg, i64* %Sp_Arg, i64* %Hp_Arg, i64 %R1_Arg, i64 %R2_Arg, i64 %R3_Arg) nounwind + ret void +}