Add GetPrevLabelInstr and GetBlockStartInstr

Author: Penguinwizzard

lib/Backend/IR.cpp

@@ -2851,6 +2851,42 @@ Instr::GetPrevRealInstrOrLabel() const
     return instr;
 }
 
+///----------------------------------------------------------------------------
+///
+/// Instr::GetPrevLabelInstr
+///
+///----------------------------------------------------------------------------
+IR::LabelInstr *
+Instr::GetPrevLabelInstr() const
+{
+    IR::Instr *instr = this->m_prev;
+
+    while (!instr->IsLabelInstr())
+    {
+        instr = instr->m_prev;
+        AssertMsg(instr, "GetPrevLabelInstr() failed...");
+    }
+    return instr->AsLabelInstr();
+}
+
+///----------------------------------------------------------------------------
+///
+/// Instr::GetPrevLabelInstr
+///
+///----------------------------------------------------------------------------
+IR::Instr *
+Instr::GetBlockStartInstr() const
+{
+    IR::Instr *instr = this->m_prev;
+
+    while (!instr->StartsBasicBlock())
+    {
+        instr = instr->m_prev;
+        AssertMsg(instr, "GetBlockStartInstr() failed...");
+    }
+    return instr;
+}
+
 ///----------------------------------------------------------------------------
 ///
 /// Instr::GetInsertBeforeByteCodeUsesInstr

lib/Backend/IR.h

@@ -295,6 +295,8 @@ class Instr
     IR::Instr *     GetNextBranchOrLabel() const;
     IR::Instr *     GetPrevRealInstr() const;
     IR::Instr *     GetPrevRealInstrOrLabel() const;
+    IR::LabelInstr *GetPrevLabelInstr() const;
+    IR::Instr *     GetBlockStartInstr() const;
     IR::Instr *     GetInsertBeforeByteCodeUsesInstr();
     IR::ByteCodeUsesInstr * GetFirstByteCodeUsesInstrBackward();
     bool            IsByteCodeUsesInstrFor(IR::Instr * instr) const;