[DebugInfo] Examine all uses of isDebugValue() for debug instructions.

Because we create a new kind of debug instruction, DBG_LABEL, we need to
check all passes which use isDebugValue() to check MachineInstr is debug
instruction or not. When expelling debug instructions, we should expel
both DBG_VALUE and DBG_LABEL. So, I create a new function,
isDebugInstr(), in MachineInstr to check whether the MachineInstr is
debug instruction or not.

This patch has no new test case. I have run regression test and there is
no difference in regression test.

Differential Revision: https://reviews.llvm.org/D45342

Patch by Hsiangkai Wang.

llvm-svn: 331844
diff --git a/llvm/lib/Target/ARM/ARMHazardRecognizer.cpp b/llvm/lib/Target/ARM/ARMHazardRecognizer.cpp
index f878bf9..d5dacbe 100644
--- a/llvm/lib/Target/ARM/ARMHazardRecognizer.cpp
+++ b/llvm/lib/Target/ARM/ARMHazardRecognizer.cpp
@@ -37,7 +37,7 @@
 
   MachineInstr *MI = SU->getInstr();
 
-  if (!MI->isDebugValue()) {
+  if (!MI->isDebugInstr()) {
     // Look for special VMLA / VMLS hazards. A VMUL / VADD / VSUB following
     // a VMLA / VMLS will cause 4 cycle stall.
     const MCInstrDesc &MCID = MI->getDesc();
@@ -81,7 +81,7 @@
 
 void ARMHazardRecognizer::EmitInstruction(SUnit *SU) {
   MachineInstr *MI = SU->getInstr();
-  if (!MI->isDebugValue()) {
+  if (!MI->isDebugInstr()) {
     LastMI = MI;
     FpMLxStalls = 0;
   }