vendor/llvm/llvm-trunk-r306956

1 files changed, 20 insertions, 4 deletions

diff --git a/lib/Target/PowerPC/PPCTLSDynamicCall.cpp b/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
index 31c50785c2ee5..5f8085f4626e2 100644
--- a/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
+++ b/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
@@ -52,6 +52,7 @@ namespace {
 protected:
     bool processBlock(MachineBasicBlock &MBB) {
       bool Changed = false;
+      bool NeedFence = true;
       bool Is64Bit = MBB.getParent()->getSubtarget<PPCSubtarget>().isPPC64();
 
       for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end();
@@ -62,6 +63,16 @@ protected:
             MI.getOpcode() != PPC::ADDItlsldLADDR &&
             MI.getOpcode() != PPC::ADDItlsgdLADDR32 &&
             MI.getOpcode() != PPC::ADDItlsldLADDR32) {
+
+          // Although we create ADJCALLSTACKDOWN and ADJCALLSTACKUP
+          // as scheduling fences, we skip creating fences if we already
+          // have existing ADJCALLSTACKDOWN/UP to avoid nesting,
+          // which causes verification error with -verify-machineinstrs.
+          if (MI.getOpcode() == PPC::ADJCALLSTACKDOWN)
+            NeedFence = false;
+          else if (MI.getOpcode() == PPC::ADJCALLSTACKUP)
+            NeedFence = true;
+
           ++I;
           continue;
         }
@@ -96,11 +107,15 @@ protected:
           break;
         }
 
-        // Don't really need to save data to the stack - the clobbered
+        // We create ADJCALLSTACKUP and ADJCALLSTACKDOWN around _tls_get_addr
+        // as schduling fence to avoid it is scheduled before
+        // mflr in the prologue and the address in LR is clobbered (PR25839).
+        // We don't really need to save data to the stack - the clobbered
         // registers are already saved when the SDNode (e.g. PPCaddiTlsgdLAddr)
         // gets translated to the pseudo instruction (e.g. ADDItlsgdLADDR).
-        BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKDOWN)).addImm(0)
-                                                            .addImm(0);
+        if (NeedFence)
+          BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKDOWN)).addImm(0)
+                                                              .addImm(0);
 
         // Expand into two ops built prior to the existing instruction.
         MachineInstr *Addi = BuildMI(MBB, I, DL, TII->get(Opc1), GPR3)
@@ -116,7 +131,8 @@ protected:
                               .addReg(GPR3));
         Call->addOperand(MI.getOperand(3));
 
-        BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKUP)).addImm(0).addImm(0);
+        if (NeedFence)
+          BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKUP)).addImm(0).addImm(0);
 
         BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), OutReg)
           .addReg(GPR3);