Fix a bad prologue / epilogue codegen bug where the compiler would emit illegal

vpush instructions to save / restore VFP / NEON registers like this:
vpush {d8,d10,d11}
vpop {d8,d10,d11}

vpush and vpop do not allow gaps in the register list.
rdar://8728956


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121197 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 132 insertions, 68 deletions

diff --git a/lib/Target/ARM/ARMFrameInfo.cpp b/lib/Target/ARM/ARMFrameInfo.cpp
index be1bd5542ba..d4aa3eb504a 100644
--- a/lib/Target/ARM/ARMFrameInfo.cpp
+++ b/lib/Target/ARM/ARMFrameInfo.cpp
@@ -500,7 +500,7 @@ int ARMFrameInfo::getFrameIndexOffset(const MachineFunction &MF, int FI) const {
 void ARMFrameInfo::emitPushInst(MachineBasicBlock &MBB,
                                 MachineBasicBlock::iterator MI,
                                 const std::vector<CalleeSavedInfo> &CSI,
-                                unsigned Opc,
+                                unsigned Opc, bool NoGap,
                                 bool(*Func)(unsigned, bool)) const {
   MachineFunction &MF = *MBB.getParent();
   const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
@@ -509,31 +509,90 @@ void ARMFrameInfo::emitPushInst(MachineBasicBlock &MBB,
   if (MI != MBB.end()) DL = MI->getDebugLoc();
 
   SmallVector<std::pair<unsigned,bool>, 4> Regs;
-  for (unsigned i = CSI.size(); i != 0; --i) {
-    unsigned Reg = CSI[i-1].getReg();
-    if (!(Func)(Reg, STI.isTargetDarwin())) continue;
-
-    // Add the callee-saved register as live-in unless it's LR and
-    // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress
-    // then it's already added to the function and entry block live-in sets.
-    bool isKill = true;
-    if (Reg == ARM::LR) {
-      if (MF.getFrameInfo()->isReturnAddressTaken() &&
-          MF.getRegInfo().isLiveIn(Reg))
-        isKill = false;
-    }
+  unsigned i = CSI.size();
+  while (i != 0) {
+    unsigned LastReg = 0;
+    for (; i != 0; --i) {
+      unsigned Reg = CSI[i-1].getReg();
+      if (!(Func)(Reg, STI.isTargetDarwin())) continue;
+
+      // Add the callee-saved register as live-in unless it's LR and
+      // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress
+      // then it's already added to the function and entry block live-in sets.
+      bool isKill = true;
+      if (Reg == ARM::LR) {
+        if (MF.getFrameInfo()->isReturnAddressTaken() &&
+            MF.getRegInfo().isLiveIn(Reg))
+          isKill = false;
+      }
+
+      if (isKill)
+        MBB.addLiveIn(Reg);
 
-    if (isKill)
-      MBB.addLiveIn(Reg);
+      if (NoGap && LastReg) {
+        if (LastReg != Reg-1)
+          break;
+      }
+      LastReg = Reg;
+      Regs.push_back(std::make_pair(Reg, isKill));
+    }
 
-    Regs.push_back(std::make_pair(Reg, isKill));
+    if (!Regs.empty()) {
+      MachineInstrBuilder MIB =
+        AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(Opc),ARM::SP)
+                       .addReg(ARM::SP));
+      for (unsigned i = 0, e = Regs.size(); i < e; ++i)
+        MIB.addReg(Regs[i].first, getKillRegState(Regs[i].second));
+      Regs.clear();
+    }
   }
+}
+
+void ARMFrameInfo::emitPopInst(MachineBasicBlock &MBB,
+                               MachineBasicBlock::iterator MI,
+                               const std::vector<CalleeSavedInfo> &CSI,
+                               unsigned Opc, bool isVarArg, bool NoGap,
+                               bool(*Func)(unsigned, bool)) const {
+  MachineFunction &MF = *MBB.getParent();
+  const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+  DebugLoc DL = MI->getDebugLoc();
+
+  SmallVector<unsigned, 4> Regs;
+  unsigned i = CSI.size();
+  while (i != 0) {
+    unsigned LastReg = 0;
+    bool DeleteRet = false;
+    for (; i != 0; --i) {
+      unsigned Reg = CSI[i-1].getReg();
+      if (!(Func)(Reg, STI.isTargetDarwin())) continue;
+
+      if (Reg == ARM::LR && !isVarArg) {
+        Reg = ARM::PC;
+        Opc = AFI->isThumbFunction() ? ARM::t2LDMIA_RET : ARM::LDMIA_RET;
+        // Fold the return instruction into the LDM.
+        DeleteRet = true;
+      }
+
+      if (NoGap && LastReg) {
+        if (LastReg != Reg-1)
+          break;
+      }
+      LastReg = Reg;
+      Regs.push_back(Reg);
+    }
 
-  if (!Regs.empty()) {
-    MachineInstrBuilder MIB = AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(Opc),
-                                                     ARM::SP).addReg(ARM::SP));
-    for (unsigned i = 0, e = Regs.size(); i < e; ++i)
-      MIB.addReg(Regs[i].first, getKillRegState(Regs[i].second));
+    if (!Regs.empty()) {
+      MachineInstrBuilder MIB =
+        AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(Opc), ARM::SP)
+                       .addReg(ARM::SP));
+      for (unsigned i = 0, e = Regs.size(); i < e; ++i)
+        MIB.addReg(Regs[i], getDefRegState(true));
+      if (DeleteRet)
+        MI->eraseFromParent();
+      MI = MIB;
+      Regs.clear();
+    }
   }
 }
 
@@ -550,49 +609,13 @@ bool ARMFrameInfo::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
 
   unsigned PushOpc = AFI->isThumbFunction() ? ARM::t2STMDB_UPD : ARM::STMDB_UPD;
   unsigned FltOpc = ARM::VSTMDDB_UPD;
-  emitPushInst(MBB, MI, CSI, PushOpc, &isARMArea1Register);
-  emitPushInst(MBB, MI, CSI, PushOpc, &isARMArea2Register);
-  emitPushInst(MBB, MI, CSI, FltOpc, &isARMArea3Register);
+  emitPushInst(MBB, MI, CSI, PushOpc, false, &isARMArea1Register);
+  emitPushInst(MBB, MI, CSI, PushOpc, false, &isARMArea2Register);
+  emitPushInst(MBB, MI, CSI, FltOpc,  true,  &isARMArea3Register);
 
   return true;
 }
 
-void ARMFrameInfo::emitPopInst(MachineBasicBlock &MBB,
-                               MachineBasicBlock::iterator MI,
-                               const std::vector<CalleeSavedInfo> &CSI,
-                               unsigned Opc, bool isVarArg,
-                               bool(*Func)(unsigned, bool)) const {
-  MachineFunction &MF = *MBB.getParent();
-  const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  DebugLoc DL = MI->getDebugLoc();
-
-  bool DeleteRet = false;
-  SmallVector<unsigned, 4> Regs;
-  for (unsigned i = CSI.size(); i != 0; --i) {
-    unsigned Reg = CSI[i-1].getReg();
-    if (!(Func)(Reg, STI.isTargetDarwin())) continue;
-
-    if (Reg == ARM::LR && !isVarArg) {
-      Reg = ARM::PC;
-      Opc = AFI->isThumbFunction() ? ARM::t2LDMIA_RET : ARM::LDMIA_RET;
-      // Fold the return instruction into the LDM.
-      DeleteRet = true;
-    }
-
-    Regs.push_back(Reg);
-  }
-
-  if (!Regs.empty()) {
-    MachineInstrBuilder MIB = AddDefaultPred(BuildMI(MBB, MI, DL, TII.get(Opc),
-                                                     ARM::SP).addReg(ARM::SP));
-    for (unsigned i = 0, e = Regs.size(); i < e; ++i)
-      MIB.addReg(Regs[i], getDefRegState(true));
-    if (DeleteRet)
-      MI->eraseFromParent();
-  }
-}
-
 bool ARMFrameInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
                                                MachineBasicBlock::iterator MI,
                                        const std::vector<CalleeSavedInfo> &CSI,
@@ -607,9 +630,9 @@ bool ARMFrameInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
 
   unsigned PopOpc = AFI->isThumbFunction() ? ARM::t2LDMIA_UPD : ARM::LDMIA_UPD;
   unsigned FltOpc = ARM::VLDMDIA_UPD;
-  emitPopInst(MBB, MI, CSI, FltOpc, isVarArg, &isARMArea3Register);
-  emitPopInst(MBB, MI, CSI, PopOpc, isVarArg, &isARMArea2Register);
-  emitPopInst(MBB, MI, CSI, PopOpc, isVarArg, &isARMArea1Register);
+  emitPopInst(MBB, MI, CSI, FltOpc, isVarArg, true,  &isARMArea3Register);
+  emitPopInst(MBB, MI, CSI, PopOpc, isVarArg, false, &isARMArea2Register);
+  emitPopInst(MBB, MI, CSI, PopOpc, isVarArg, false, &isARMArea1Register);
 
   return true;
 }
diff --git a/lib/Target/ARM/ARMFrameInfo.h b/lib/Target/ARM/ARMFrameInfo.h
index 886f7492ab5..2ff77b4b49f 100644
--- a/lib/Target/ARM/ARMFrameInfo.h
+++ b/lib/Target/ARM/ARMFrameInfo.h
@@ -58,12 +58,13 @@ public:
                                             RegScavenger *RS) const;
 
  private:
-  void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
-                   const std::vector<CalleeSavedInfo> &CSI, unsigned Opc,
-                   bool isVarArg, bool(*Func)(unsigned, bool)) const;
   void emitPushInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
                     const std::vector<CalleeSavedInfo> &CSI, unsigned Opc,
-                    bool(*Func)(unsigned, bool)) const;
+                    bool NoGap, bool(*Func)(unsigned, bool)) const;
+  void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
+                   const std::vector<CalleeSavedInfo> &CSI, unsigned Opc,
+                   bool isVarArg, bool NoGap,
+                   bool(*Func)(unsigned, bool)) const;
 };
 
 } // End llvm namespace
diff --git a/test/CodeGen/ARM/2010-12-07-PEIBug.ll b/test/CodeGen/ARM/2010-12-07-PEIBug.ll
new file mode 100644
index 00000000000..c65952be3c6
--- /dev/null
+++ b/test/CodeGen/ARM/2010-12-07-PEIBug.ll
@@ -0,0 +1,40 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 -mcpu=cortex-a8 | FileCheck %s
+; rdar://8728956
+
+define hidden void @foo() nounwind ssp {
+entry:
+; CHECK: foo:
+; CHECK: push {r7, lr}
+; CHECK-NEXT: mov r7, sp
+; CHECK-NEXT: vpush {d8}
+; CHECK-NEXT: vpush {d10, d11}
+  %tmp40 = load <4 x i8>* undef
+  %tmp41 = extractelement <4 x i8> %tmp40, i32 2
+  %conv42 = zext i8 %tmp41 to i32
+  %conv43 = sitofp i32 %conv42 to float
+  %div44 = fdiv float %conv43, 2.560000e+02
+  %vecinit45 = insertelement <4 x float> undef, float %div44, i32 2
+  %vecinit46 = insertelement <4 x float> %vecinit45, float 1.000000e+00, i32 3
+  store <4 x float> %vecinit46, <4 x float>* undef
+  br i1 undef, label %if.then105, label %if.else109
+
+if.then105:                                       ; preds = %entry
+  br label %if.end114
+
+if.else109:                                       ; preds = %entry
+  br label %if.end114
+
+if.end114:                                        ; preds = %if.else109, %if.then105
+  %call185 = call float @bar()
+  %vecinit186 = insertelement <4 x float> undef, float %call185, i32 1
+  %call189 = call float @bar()
+  %vecinit190 = insertelement <4 x float> %vecinit186, float %call189, i32 2
+  %vecinit191 = insertelement <4 x float> %vecinit190, float 1.000000e+00, i32 3
+  store <4 x float> %vecinit191, <4 x float>* undef
+; CHECK: vpop {d10, d11}
+; CHECK-NEXT: vpop {d8}
+; CHECK-NEXT: pop {r7, pc}
+  ret void
+}
+
+declare hidden float @bar() nounwind readnone ssp