diff --git a/include/llvm/CodeGen/SlotIndexes.h b/include/llvm/CodeGen/SlotIndexes.h index 19bcb92f01e..774a0f5443b 100644 --- a/include/llvm/CodeGen/SlotIndexes.h +++ b/include/llvm/CodeGen/SlotIndexes.h @@ -208,6 +208,12 @@ namespace llvm { return A.lie.getPointer() == B.lie.getPointer(); } + /// isEarlierInstr - Return true if A refers to an instruction earlier than + /// B. This is equivalent to A < B && !isSameInstr(A, B). + static bool isEarlierInstr(SlotIndex A, SlotIndex B) { + return A.entry().getIndex() < B.entry().getIndex(); + } + /// Return the distance from this index to the given one. int distance(SlotIndex other) const { return other.getIndex() - getIndex(); diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp index 9dc5c219317..379025b5a9a 100644 --- a/lib/CodeGen/SplitKit.cpp +++ b/lib/CodeGen/SplitKit.cpp @@ -62,13 +62,14 @@ SlotIndex SplitAnalysis::computeLastSplitPoint(unsigned Num) { const MachineBasicBlock *MBB = MF.getBlockNumbered(Num); const MachineBasicBlock *LPad = MBB->getLandingPadSuccessor(); std::pair &LSP = LastSplitPoint[Num]; + SlotIndex MBBEnd = LIS.getMBBEndIdx(MBB); // Compute split points on the first call. The pair is independent of the // current live interval. if (!LSP.first.isValid()) { MachineBasicBlock::const_iterator FirstTerm = MBB->getFirstTerminator(); if (FirstTerm == MBB->end()) - LSP.first = LIS.getMBBEndIdx(MBB); + LSP.first = MBBEnd; else LSP.first = LIS.getInstructionIndex(FirstTerm); @@ -89,10 +90,24 @@ SlotIndex SplitAnalysis::computeLastSplitPoint(unsigned Num) { // If CurLI is live into a landing pad successor, move the last split point // back to the call that may throw. - if (LPad && LSP.second.isValid() && LIS.isLiveInToMBB(*CurLI, LPad)) - return LSP.second; - else + if (!LPad || !LSP.second || !LIS.isLiveInToMBB(*CurLI, LPad)) return LSP.first; + + // Find the value leaving MBB. + const VNInfo *VNI = CurLI->getVNInfoBefore(MBBEnd); + if (!VNI) + return LSP.first; + + // If the value leaving MBB was defined after the call in MBB, it can't + // really be live-in to the landing pad. This can happen if the landing pad + // has a PHI, and this register is undef on the exceptional edge. + // + if (!SlotIndex::isEarlierInstr(VNI->def, LSP.second) && VNI->def < MBBEnd) + return LSP.first; + + // Value is properly live-in to the landing pad. + // Only allow splits before the call. + return LSP.second; } MachineBasicBlock::iterator diff --git a/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll b/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll new file mode 100644 index 00000000000..832a8eb8144 --- /dev/null +++ b/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll @@ -0,0 +1,155 @@ +; RUN: llc < %s -disable-fp-elim +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32-S128" +target triple = "i386-apple-macosx10.7" + +; This test case has a landing pad with two predecessors, and a variable that +; is undef on the first edge while carrying the first function return value on +; the second edge. +; +; Live range splitting tries to isolate the block containing the first function +; call, and it is important that the last split point is after the function call +; so the return value can spill. +; +; + +@Exception = external unnamed_addr constant { i8*, i8* } + +declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind + +define void @f(i32* nocapture %arg, i32* nocapture %arg1, i32* nocapture %arg2, i32* nocapture %arg3, i32 %arg4, i32 %arg5) optsize ssp { +bb: + br i1 undef, label %bb6, label %bb7 + +bb6: ; preds = %bb + %tmp = select i1 false, i32 0, i32 undef + br label %bb7 + +bb7: ; preds = %bb6, %bb + %tmp8 = phi i32 [ %tmp, %bb6 ], [ 0, %bb ] + %tmp9 = shl i32 %tmp8, 2 + %tmp10 = invoke noalias i8* @_Znam(i32 undef) optsize + to label %bb11 unwind label %bb20 + +bb11: ; preds = %bb7 + %tmp12 = ptrtoint i8* %tmp10 to i32 + %tmp13 = bitcast i8* %tmp10 to i32* + %tmp14 = shl i32 %tmp8, 2 + %tmp15 = getelementptr i32* %tmp13, i32 undef + %tmp16 = getelementptr i32* %tmp13, i32 undef + %tmp17 = zext i32 %tmp9 to i64 + %tmp18 = add i64 %tmp17, -1 + %tmp19 = icmp ugt i64 %tmp18, 4294967295 + br i1 %tmp19, label %bb29, label %bb31 + +bb20: ; preds = %bb43, %bb41, %bb29, %bb7 + %tmp21 = phi i32 [ undef, %bb7 ], [ %tmp12, %bb43 ], [ %tmp12, %bb29 ], [ %tmp12, %bb41 ] + %tmp22 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) + catch i8* bitcast ({ i8*, i8* }* @Exception to i8*) + br i1 undef, label %bb23, label %bb69 + +bb23: ; preds = %bb38, %bb20 + %tmp24 = phi i32 [ %tmp12, %bb38 ], [ %tmp21, %bb20 ] + %tmp25 = icmp eq i32 %tmp24, 0 + br i1 %tmp25, label %bb28, label %bb26 + +bb26: ; preds = %bb23 + %tmp27 = inttoptr i32 %tmp24 to i8* + br label %bb28 + +bb28: ; preds = %bb26, %bb23 + ret void + +bb29: ; preds = %bb11 + invoke void @OnOverFlow() optsize + to label %bb30 unwind label %bb20 + +bb30: ; preds = %bb29 + unreachable + +bb31: ; preds = %bb11 + %tmp32 = bitcast i32* %tmp15 to i8* + %tmp33 = zext i32 %tmp8 to i64 + %tmp34 = add i64 %tmp33, -1 + %tmp35 = icmp ugt i64 %tmp34, 4294967295 + %tmp36 = icmp sgt i32 %tmp8, 0 + %tmp37 = add i32 %tmp9, -4 + br label %bb38 + +bb38: ; preds = %bb67, %bb31 + %tmp39 = phi i32 [ %tmp68, %bb67 ], [ undef, %bb31 ] + %tmp40 = icmp sgt i32 %tmp39, undef + br i1 %tmp40, label %bb41, label %bb23 + +bb41: ; preds = %bb38 + invoke void @Pjii(i32* %tmp16, i32 0, i32 %tmp8) optsize + to label %bb42 unwind label %bb20 + +bb42: ; preds = %bb41 + tail call void @llvm.memset.p0i8.i32(i8* %tmp32, i8 0, i32 %tmp9, i32 1, i1 false) nounwind + br i1 %tmp35, label %bb43, label %bb45 + +bb43: ; preds = %bb42 + invoke void @OnOverFlow() optsize + to label %bb44 unwind label %bb20 + +bb44: ; preds = %bb43 + unreachable + +bb45: ; preds = %bb57, %bb42 + %tmp46 = phi i32 [ %tmp58, %bb57 ], [ 255, %bb42 ] + %tmp47 = icmp slt i32 undef, 0 + br i1 %tmp47, label %bb48, label %bb59 + +bb48: ; preds = %bb45 + tail call void @llvm.memset.p0i8.i32(i8* %tmp32, i8 0, i32 %tmp9, i32 1, i1 false) nounwind + br i1 %tmp36, label %bb49, label %bb57 + +bb49: ; preds = %bb49, %bb48 + %tmp50 = phi i32 [ %tmp55, %bb49 ], [ 0, %bb48 ] + %tmp51 = add i32 %tmp50, undef + %tmp52 = add i32 %tmp50, undef + %tmp53 = getelementptr i32* %tmp13, i32 %tmp52 + %tmp54 = load i32* %tmp53, align 4, !tbaa !0 + %tmp55 = add i32 %tmp50, 1 + %tmp56 = icmp eq i32 %tmp55, %tmp8 + br i1 %tmp56, label %bb57, label %bb49 + +bb57: ; preds = %bb49, %bb48 + %tmp58 = add i32 %tmp46, -1 + br label %bb45 + +bb59: ; preds = %bb45 + %tmp60 = ashr i32 %tmp46, 31 + tail call void @llvm.memset.p0i8.i32(i8* null, i8 0, i32 %tmp37, i32 1, i1 false) nounwind + br i1 %tmp36, label %bb61, label %bb67 + +bb61: ; preds = %bb61, %bb59 + %tmp62 = phi i32 [ %tmp65, %bb61 ], [ 0, %bb59 ] + %tmp63 = add i32 %tmp62, %tmp14 + %tmp64 = getelementptr i32* %tmp13, i32 %tmp63 + store i32 0, i32* %tmp64, align 4, !tbaa !0 + %tmp65 = add i32 %tmp62, 1 + %tmp66 = icmp eq i32 %tmp65, %tmp8 + br i1 %tmp66, label %bb67, label %bb61 + +bb67: ; preds = %bb61, %bb59 + %tmp68 = add i32 %tmp39, -1 + br label %bb38 + +bb69: ; preds = %bb20 + resume { i8*, i32 } %tmp22 +} + +declare i32 @__gxx_personality_v0(...) + +declare noalias i8* @_Znam(i32) optsize + +declare void @Pjii(i32*, i32, i32) optsize + +declare i32 @llvm.eh.typeid.for(i8*) nounwind readnone + +declare void @OnOverFlow() noreturn optsize ssp align 2 + +!0 = metadata !{metadata !"int", metadata !1} +!1 = metadata !{metadata !"omnipotent char", metadata !2} +!2 = metadata !{metadata !"Simple C/C++ TBAA", null}