eliminate need of flex
[fw/sdcc] / src / SDCCopt.c
index a884ab9a457aad15cd7dff9ee515485386816b5c..94ee6e187b5d0231dc418575b510578387eb20cd 100644 (file)
@@ -106,28 +106,30 @@ cnvToFcall (iCode * ic, eBBlock * ebp)
     {
 
       /* first one */
-      if (IS_REGPARM (func->args->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
        {
          newic = newiCode (SEND, IC_LEFT (ic), NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
        }
       else
        {
          newic = newiCode ('=', NULL, IC_LEFT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
        }
 
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
 
       /* second one */
-      if (IS_REGPARM (func->args->next->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
        {
-         newic = newiCode (SEND, IC_LEFT (ic), NULL);
+         newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
        }
       else
        {
          newic = newiCode ('=', NULL, IC_RIGHT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args->next);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type)->next);
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
@@ -137,30 +139,34 @@ cnvToFcall (iCode * ic, eBBlock * ebp)
     {
 
       /* push right */
-      if (IS_REGPARM (func->args->next->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
        {
          newic = newiCode (SEND, right, NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
        }
       else
        {
          newic = newiCode (IPUSH, right, NULL);
          newic->parmPush = 1;
-         bytesPushed+=4;
+         //bytesPushed+=4;
+         bytesPushed += getSize(operandType(right));
        }
 
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
 
       /* insert push left */
-      if (IS_REGPARM (func->args->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
        {
          newic = newiCode (SEND, left, NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
        }
       else
        {
          newic = newiCode (IPUSH, left, NULL);
          newic->parmPush = 1;
-         bytesPushed+=4;
+         //bytesPushed+=4;
+         bytesPushed += getSize(operandType(left));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
@@ -170,6 +176,23 @@ cnvToFcall (iCode * ic, eBBlock * ebp)
   IC_RESULT (newic) = IC_RESULT (ic);
   newic->lineno = lineno;
   newic->parmBytes+=bytesPushed;
+  ebp->hasFcall = 1;
+  if (currFunc)
+    FUNC_HASFCALL (currFunc->type) = 1;
+    
+  if(TARGET_IS_PIC16) {
+       /* normally these functions aren't marked external, so we can use their
+        * _extern field to marked as already added to symbol table */
+
+       if(!SPEC_EXTR(func->etype)) {
+           memmap *seg = SPEC_OCLS(OP_SYMBOL(IC_LEFT(newic))->etype);
+               
+               SPEC_EXTR(func->etype) = 1;
+               seg = SPEC_OCLS( func->etype );
+               addSet(&seg->syms, func);
+       }
+  }
+
   addiCodeToeBBlock (ebp, newic, ip);
 }
 
@@ -180,10 +203,11 @@ static void
 cnvToFloatCast (iCode * ic, eBBlock * ebp)
 {
   iCode *ip, *newic;
-  symbol *func;
+  symbol *func = NULL;
   sym_link *type = operandType (IC_RIGHT (ic));
   int linenno = ic->lineno;
   int bwd, su;
+  int bytesPushed=0;
 
   ip = ic->next;
   /* remove it from the iCode */
@@ -207,12 +231,15 @@ found:
   if (!options.float_rent)
     {
       /* first one */
-      if (IS_REGPARM (func->args->etype))
-       newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+       if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) 
+           {
+               newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+               newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
+           }
       else
        {
          newic = newiCode ('=', NULL, IC_RIGHT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = linenno;
@@ -221,12 +248,15 @@ found:
   else
     {
       /* push the left */
-      if (IS_REGPARM (func->args->etype))
-       newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+       if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
+           newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+           newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
+       }
       else
        {
          newic = newiCode (IPUSH, IC_RIGHT (ic), NULL);
          newic->parmPush = 1;
+         bytesPushed += getSize(operandType(IC_RIGHT(ic)));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = linenno;
@@ -236,9 +266,26 @@ found:
   /* make the call */
   newic = newiCode (CALL, operandFromSymbol (func), NULL);
   IC_RESULT (newic) = IC_RESULT (ic);
+  newic->parmBytes+=bytesPushed;
+  ebp->hasFcall = 1;
+  if (currFunc)
+    FUNC_HASFCALL (currFunc->type) = 1;
+
+  if(TARGET_IS_PIC16) {
+       /* normally these functions aren't marked external, so we can use their
+        * _extern field to marked as already added to symbol table */
+
+       if(!SPEC_EXTR(func->etype)) {
+           memmap *seg = SPEC_OCLS(OP_SYMBOL(IC_LEFT(newic))->etype);
+               
+               SPEC_EXTR(func->etype) = 1;
+               seg = SPEC_OCLS( func->etype );
+               addSet(&seg->syms, func);
+       }
+  }
+
   addiCodeToeBBlock (ebp, newic, ip);
   newic->lineno = linenno;
-
 }
 
 /*-----------------------------------------------------------------*/
@@ -248,10 +295,11 @@ static void
 cnvFromFloatCast (iCode * ic, eBBlock * ebp)
 {
   iCode *ip, *newic;
-  symbol *func;
+  symbol *func = NULL;
   sym_link *type = operandType (IC_LEFT (ic));
   int lineno = ic->lineno;
   int bwd, su;
+  int bytesPushed=0;
 
   ip = ic->next;
   /* remove it from the iCode */
@@ -276,12 +324,14 @@ found:
   if (!options.float_rent)
     {
       /* first one */
-      if (IS_REGPARM (func->args->etype))
-       newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+       if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
+           newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+           newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
+       }
       else
        {
          newic = newiCode ('=', NULL, IC_RIGHT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
@@ -291,12 +341,15 @@ found:
     {
 
       /* push the left */
-      if (IS_REGPARM (func->args->etype))
-       newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+       if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
+           newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+           newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
+       }
       else
        {
          newic = newiCode (IPUSH, IC_RIGHT (ic), NULL);
          newic->parmPush = 1;
+         bytesPushed += getSize(operandType(IC_RIGHT(ic)));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
@@ -306,11 +359,30 @@ found:
   /* make the call */
   newic = newiCode (CALL, operandFromSymbol (func), NULL);
   IC_RESULT (newic) = IC_RESULT (ic);
+  newic->parmBytes+=bytesPushed;
+  ebp->hasFcall = 1;
+  if (currFunc)
+    FUNC_HASFCALL (currFunc->type) = 1;
+
+  if(TARGET_IS_PIC16) {
+       /* normally these functions aren't marked external, so we can use their
+        * _extern field to marked as already added to symbol table */
+
+       if(!SPEC_EXTR(func->etype)) {
+           memmap *seg = SPEC_OCLS(OP_SYMBOL(IC_LEFT(newic))->etype);
+               
+               SPEC_EXTR(func->etype) = 1;
+               seg = SPEC_OCLS( func->etype );
+               addSet(&seg->syms, func);
+       }
+  }
+
   addiCodeToeBBlock (ebp, newic, ip);
   newic->lineno = lineno;
-
 }
 
+extern operand *geniCodeRValue (operand *, bool);
+
 /*-----------------------------------------------------------------*/
 /* convilong - converts int or long mults or divs to fcalls        */
 /*-----------------------------------------------------------------*/
@@ -325,8 +397,34 @@ convilong (iCode * ic, eBBlock * ebp, sym_link * type, int op)
   int su;
   int bytesPushed=0;
 
-  remiCodeFromeBBlock (ebp, ic);
-
+  // Easy special case which avoids function call: modulo by a literal power 
+  // of two can be replaced by a bitwise AND.
+  if (op == '%' && isOperandLiteral(IC_RIGHT(ic)))
+  {
+      unsigned litVal = (unsigned)(operandLitValue(IC_RIGHT(ic)));
+      
+      // See if literal value is a power of 2.
+      while (litVal && !(litVal & 1))
+      {
+         litVal >>= 1;
+      }
+      if (litVal)
+      {
+         // discard first high bit set.
+         litVal >>= 1;
+      }
+         
+      if (!litVal)
+      {
+         ic->op = BITWISEAND;
+         IC_RIGHT(ic) = operandFromLit(operandLitValue(IC_RIGHT(ic)) - 1);
+         return;
+      }
+  }
+    
+  remiCodeFromeBBlock (ebp, ic);    
+    
+    
   /* depending on the type */
   for (bwd = 0; bwd < 3; bwd++)
     {
@@ -360,23 +458,27 @@ found:
   if (!options.intlong_rent)
     {
       /* first one */
-      if (IS_REGPARM (func->args->etype))
-       newic = newiCode (SEND, IC_LEFT (ic), NULL);
+       if (IS_REGPARM (FUNC_ARGS(func->type)->etype)) {
+           newic = newiCode (SEND, IC_LEFT (ic), NULL);
+           newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
+       }
       else
        {
          newic = newiCode ('=', NULL, IC_LEFT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type));
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
 
       /* second one */
-      if (IS_REGPARM (func->args->next->etype))
-       newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+      if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype)) {
+         newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
+      }
       else
        {
          newic = newiCode ('=', NULL, IC_RIGHT (ic));
-         IC_RESULT (newic) = operandFromValue (func->args->next);
+         IC_RESULT (newic) = operandFromValue (FUNC_ARGS(func->type)->next);
        }
       addiCodeToeBBlock (ebp, newic, ip);
       newic->lineno = lineno;
@@ -386,9 +488,10 @@ found:
     {
       /* compiled as reentrant then push */
       /* push right */
-      if (IS_REGPARM (func->args->next->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->next->etype))
         {
           newic = newiCode (SEND, IC_RIGHT (ic), NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->next->etype);
         }
       else
        {
@@ -401,9 +504,10 @@ found:
       newic->lineno = lineno;
 
       /* insert push left */
-      if (IS_REGPARM (func->args->etype))
+      if (IS_REGPARM (FUNC_ARGS(func->type)->etype))
         {
           newic = newiCode (SEND, IC_LEFT (ic), NULL);
+         newic->argreg = SPEC_ARGREG(FUNC_ARGS(func->type)->etype);
         }
       else
        {
@@ -422,6 +526,23 @@ found:
   IC_RESULT (newic) = IC_RESULT (ic);
   newic->lineno = lineno;
   newic->parmBytes+=bytesPushed; // to clear the stack after the call
+  ebp->hasFcall = 1;
+  if (currFunc)
+    FUNC_HASFCALL (currFunc->type) = 1;
+
+  if(TARGET_IS_PIC16) {
+       /* normally these functions aren't marked external, so we can use their
+        * _extern field to marked as already added to symbol table */
+
+       if(!SPEC_EXTR(func->etype)) {
+           memmap *seg = SPEC_OCLS(OP_SYMBOL(IC_LEFT(newic))->etype);
+               
+               SPEC_EXTR(func->etype) = 1;
+               seg = SPEC_OCLS( func->etype );
+               addSet(&seg->syms, func);
+       }
+  }
+
   addiCodeToeBBlock (ebp, newic, ip);
 }
 
@@ -464,10 +585,21 @@ convertToFcall (eBBlock ** ebbs, int count)
          /* if long / int mult or divide or mod */
          if (ic->op == '*' || ic->op == '/' || ic->op == '%')
            {
-             sym_link *type = operandType (IC_LEFT (ic));
-             if (IS_INTEGRAL (type) && getSize (type) > port->support.muldiv)
+             sym_link *leftType = operandType (IC_LEFT (ic));
+
+             if (IS_INTEGRAL (leftType) && getSize (leftType) > port->support.muldiv)
                 {
-                  convilong (ic, ebbs[i], type, ic->op);
+                  sym_link *rightType = operandType (IC_RIGHT (ic));
+
+                  if (port->hasNativeMulFor != NULL &&
+                      port->hasNativeMulFor (ic, leftType, rightType))
+                    {
+                      /* Leave as native */
+                    }
+                  else
+                    {
+                      convilong (ic, ebbs[i], leftType, ic->op);
+                    }
                 }
            }
           
@@ -484,6 +616,31 @@ convertToFcall (eBBlock ** ebbs, int count)
     }
 }
 
+/*-----------------------------------------------------------------*/
+/* isLocalWithoutDef - return 1 if sym might be used without a     */
+/*                     defining iCode                              */
+/*-----------------------------------------------------------------*/
+static int
+isLocalWithoutDef (symbol * sym)
+{
+  if (!IS_AUTO (sym))
+    return 0;
+  
+  if (IS_VOLATILE (sym->type))
+    return 0;
+  
+  if (sym->_isparm)
+    return 0;
+  
+  if (IS_AGGREGATE (sym->type))
+    return 0;
+  
+  if (sym->addrtaken)
+    return 0;
+  
+  return !sym->defs;
+}
+
 /*-----------------------------------------------------------------*/
 /* replaceRegEqv - replace all local variables with their reqv     */
 /*-----------------------------------------------------------------*/
@@ -492,6 +649,12 @@ replaceRegEqv (eBBlock ** ebbs, int count)
 {
   int i;
 
+  /* Update the symbols' def bitvector so we know if there is   */
+  /* a defining iCode or not. Only replace a local variable     */
+  /* with its register equivalent if there is a defining iCode; */
+  /* otherwise, the port's register allocater may choke.        */
+  cseAllBlocks (ebbs, count, TRUE);
+
   for (i = 0; i < count; i++)
     {
 
@@ -505,7 +668,17 @@ replaceRegEqv (eBBlock ** ebbs, int count)
 
          if (ic->op == IFX)
            {
-
+             if (IC_COND (ic) &&
+                 IS_TRUE_SYMOP (IC_COND (ic)) &&
+                  isLocalWithoutDef (OP_SYMBOL (IC_COND (ic))))
+               {
+                 werrorfl (ic->filename, ic->lineno,
+                         W_LOCAL_NOINIT,
+                         OP_SYMBOL (IC_COND (ic))->name);
+                 OP_REQV (IC_COND (ic)) = NULL;
+                 OP_SYMBOL (IC_COND (ic))->allocreq = 1;
+               }
+             
              if (IS_TRUE_SYMOP (IC_COND (ic)) &&
                  OP_REQV (IC_COND (ic)))
                IC_COND (ic) = opFromOpWithDU (OP_REQV (IC_COND (ic)),
@@ -515,8 +688,20 @@ replaceRegEqv (eBBlock ** ebbs, int count)
              continue;
            }
 
+         
          if (ic->op == JUMPTABLE)
            {
+             if (IC_JTCOND (ic) &&
+                 IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
+                  isLocalWithoutDef (OP_SYMBOL (IC_JTCOND (ic))))
+               {
+                 werrorfl (ic->filename, ic->lineno,
+                         W_LOCAL_NOINIT,
+                         OP_SYMBOL (IC_JTCOND (ic))->name);
+                 OP_REQV (IC_JTCOND (ic)) = NULL;
+                 OP_SYMBOL (IC_JTCOND (ic))->allocreq = 1;
+               }
+             
              if (IS_TRUE_SYMOP (IC_JTCOND (ic)) &&
                  OP_REQV (IC_JTCOND (ic)))
                IC_JTCOND (ic) = opFromOpWithDU (OP_REQV (IC_JTCOND (ic)),
@@ -549,6 +734,17 @@ replaceRegEqv (eBBlock ** ebbs, int count)
                                          OP_SYMBOL (IC_RESULT (ic))->uses);
            }
 
+         if (IC_RIGHT (ic) &&
+             IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
+             isLocalWithoutDef (OP_SYMBOL (IC_RIGHT (ic))))
+           {
+             werrorfl (ic->filename, ic->lineno,
+                       W_LOCAL_NOINIT,
+                       OP_SYMBOL (IC_RIGHT (ic))->name);
+             OP_REQV (IC_RIGHT (ic)) = NULL;
+             OP_SYMBOL (IC_RIGHT (ic))->allocreq = 1;
+           }
+         
          if (IC_RIGHT (ic) &&
              IS_TRUE_SYMOP (IC_RIGHT (ic)) &&
              OP_REQV (IC_RIGHT (ic)))
@@ -559,6 +755,17 @@ replaceRegEqv (eBBlock ** ebbs, int count)
              IC_RIGHT (ic)->isaddr = 0;
            }
 
+         if (IC_LEFT (ic) &&
+             IS_TRUE_SYMOP (IC_LEFT (ic)) &&
+             isLocalWithoutDef (OP_SYMBOL (IC_LEFT (ic))))
+           {
+             werrorfl (ic->filename, ic->lineno,
+                       W_LOCAL_NOINIT,
+                       OP_SYMBOL (IC_LEFT (ic))->name);
+             OP_REQV (IC_LEFT (ic)) = NULL;
+             OP_SYMBOL (IC_LEFT (ic))->allocreq = 1;
+           }
+            
          if (IC_LEFT (ic) &&
              IS_TRUE_SYMOP (IC_LEFT (ic)) &&
              OP_REQV (IC_LEFT (ic)))
@@ -572,6 +779,51 @@ replaceRegEqv (eBBlock ** ebbs, int count)
     }
 }
 
+/*-----------------------------------------------------------------*/
+/* findReqv - search for a register equivalent                     */
+/*-----------------------------------------------------------------*/
+operand *
+findReqv (symbol * prereqv, eBBlock ** ebbs, int count)
+{
+  int i;
+  iCode * ic;
+  
+  /* for all blocks do */
+  for (i=0; i<count; i++)
+    {
+      /* for all instructions in the block do */
+      for (ic = ebbs[i]->sch; ic; ic = ic->next)
+       {
+         if (ic->op == IFX)
+           {
+             if (IS_ITEMP (IC_COND (ic))
+                 && OP_SYMBOL (IC_COND (ic))->prereqv == prereqv)
+               return IC_COND (ic);
+           }
+         else if (ic->op == JUMPTABLE)
+           {
+             if (IS_ITEMP (IC_JTCOND (ic))
+                 && OP_SYMBOL (IC_JTCOND (ic))->prereqv == prereqv)
+               return IC_JTCOND (ic);
+           }
+         else
+           {
+             if (IS_ITEMP (IC_LEFT (ic))
+                 && OP_SYMBOL (IC_LEFT (ic))->prereqv == prereqv)
+               return IC_LEFT (ic);
+             if (IS_ITEMP (IC_RIGHT (ic))
+                 && OP_SYMBOL (IC_RIGHT (ic))->prereqv == prereqv)
+               return IC_RIGHT (ic);
+             if (IS_ITEMP (IC_RESULT (ic))
+                 && OP_SYMBOL (IC_RESULT (ic))->prereqv == prereqv)
+               return IC_RESULT (ic);
+           }
+       }
+    }
+  
+  return NULL;
+}
+
 /*-----------------------------------------------------------------*/
 /* killDeadCode - eliminates dead assignments                      */
 /*-----------------------------------------------------------------*/
@@ -613,9 +865,16 @@ killDeadCode (eBBlock ** ebbs, int count)
 
              if (SKIP_IC (ic) ||
                  ic->op == IFX ||
-                 ic->op == RETURN)
+                 ic->op == RETURN ||
+                  ic->op == DUMMY_READ_VOLATILE ||
+                  ic->op == CRITICAL ||
+                  ic->op == ENDCRITICAL)
                continue;
 
+             /* Since both IFX & JUMPTABLE (in SKIP_IC) have been tested for */
+             /* it is now safe to assume IC_LEFT, IC_RIGHT, & IC_RESULT are  */
+             /* valid. */
+
              /* if the result is volatile then continue */
              if (IC_RESULT (ic) && isOperandVolatile (IC_RESULT (ic), FALSE))
                continue;
@@ -623,6 +882,10 @@ killDeadCode (eBBlock ** ebbs, int count)
              /* if the result is a temp & isaddr then skip */
              if (IC_RESULT (ic) && POINTER_SET (ic))
                continue;
+              
+              if (POINTER_GET (ic) && IS_VOLATILE (operandType (IC_LEFT (ic))->next)
+                 && !SPIL_LOC (IC_RESULT (ic)))
+                continue;
 
              /* if the result is used in the remainder of the */
              /* block then skip */
@@ -659,17 +922,45 @@ killDeadCode (eBBlock ** ebbs, int count)
                    continue;
 
                  kill = 1;
-               }
+                }
 
            kill:
              /* kill this one if required */
              if (kill)
                {
+                 bool volLeft = IS_SYMOP (IC_LEFT (ic))
+                                && isOperandVolatile (IC_LEFT (ic), FALSE);
+                 bool volRight = IS_SYMOP (IC_RIGHT (ic)) 
+                                 && isOperandVolatile (IC_RIGHT (ic), FALSE);
+
+                 /* a dead address-of operation should die, even if volatile */
+                 if (ic->op == ADDRESS_OF)
+                   volLeft = FALSE;
+
+                 if (ic->next && ic->seqPoint == ic->next->seqPoint
+                     && (ic->next->op == '+' || ic->next->op == '-'))
+                   {
+                     if (isOperandEqual (IC_LEFT(ic), IC_LEFT(ic->next))
+                         || isOperandEqual (IC_LEFT(ic), IC_RIGHT(ic->next)))
+                       volLeft = FALSE;
+                     if (isOperandEqual (IC_RIGHT(ic), IC_LEFT(ic->next))
+                         || isOperandEqual (IC_RIGHT(ic), IC_RIGHT(ic->next)))
+                       volRight = FALSE;
+                   }
+                 
+                 if (POINTER_GET (ic) && IS_VOLATILE (operandType (IC_LEFT (ic))->next))
+                   {
+                     if (SPIL_LOC (IC_RESULT (ic)))
+                       {
+                         IC_RESULT (ic) = newiTempFromOp (IC_RESULT (ic));
+                         SPIL_LOC (IC_RESULT (ic)) = NULL;
+                       }
+                     continue;
+                   }
+                 
                  change = 1;
                  gchange++;
-                 /* eliminate this */
-                 remiCodeFromeBBlock (ebbs[i], ic);
-
+                 
                  /* now delete from defUseSet */
                  deleteItemIf (&ebbs[i]->outExprs, ifDiCodeIsX, ic);
                  bitVectUnSetBit (ebbs[i]->outDefs, ic->key);
@@ -677,12 +968,56 @@ killDeadCode (eBBlock ** ebbs, int count)
                  /* and defset of the block */
                  bitVectUnSetBit (ebbs[i]->defSet, ic->key);
 
-                 /* for the left & right remove the usage */
-                 if (IS_SYMOP (IC_LEFT (ic)))
-                   bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
+                 /* If this is the last of a register equivalent, */
+                 /* look for a successor register equivalent. */
+                 bitVectUnSetBit (OP_DEFS (IC_RESULT (ic)), ic->key);
+                 if (IS_ITEMP (IC_RESULT (ic))
+                     && OP_SYMBOL (IC_RESULT (ic))->isreqv
+                     && bitVectIsZero (OP_DEFS (IC_RESULT (ic))))
+                   {
+                     symbol * resultsym = OP_SYMBOL (IC_RESULT (ic));
+                     symbol * prereqv = resultsym->prereqv;
+                     
+                     if (OP_SYMBOL (prereqv->reqv) == resultsym)
+                       {
+                         operand * newreqv;
+
+                         IC_RESULT (ic) = NULL;
+                         newreqv = findReqv (prereqv, ebbs, count);
+                         if (newreqv)
+                           {
+                             prereqv->reqv = newreqv;
+                           }
+                       }
+                   }
+
+                 /* delete the result */
+                 IC_RESULT (ic) = NULL;
+                 
+                 if (volLeft || volRight)
+                   {
+                     /* something is volatile, so keep the iCode */
+                     /* and change the operator instead */
+                     ic->op = DUMMY_READ_VOLATILE;
+
+                     /* keep only the volatile operands */      
+                     if (!volLeft)
+                       IC_LEFT (ic) = NULL;
+                     if (!volRight)
+                       IC_RIGHT (ic) = NULL;
+                   }
+                 else
+                   {
+                     /* nothing is volatile, eliminate the iCode */
+                     remiCodeFromeBBlock (ebbs[i], ic);
+
+                     /* for the left & right remove the usage */
+                     if (IS_SYMOP (IC_LEFT (ic)))
+                       bitVectUnSetBit (OP_USES (IC_LEFT (ic)), ic->key);
 
-                 if (IS_SYMOP (IC_RIGHT (ic)))
-                   bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
+                     if (IS_SYMOP (IC_RIGHT (ic)))
+                       bitVectUnSetBit (OP_USES (IC_RIGHT (ic)), ic->key);
+                   }
                }
 
            }                   /* end of all instructions */
@@ -748,6 +1083,76 @@ discardDeadParamReceives (eBBlock ** ebbs, int count)
     }
 }
 
+/*-----------------------------------------------------------------*/
+/* optimizeCastCast - remove unneeded intermediate casts.          */
+/* Integer promotion may cast (un)signed char to int and then      */
+/* recast the int to (un)signed long. If the signedness of the     */
+/* char and long are the same, the cast can be safely performed in */
+/* a single step.                                                  */
+/*-----------------------------------------------------------------*/
+static void 
+optimizeCastCast (eBBlock ** ebbs, int count)
+{
+  int i;
+  iCode *ic;
+  iCode *uic;
+  sym_link * type1;
+  sym_link * type2;
+  sym_link * type3;
+  symbol * sym;
+
+  for (i = 0; i < count; i++)
+    {
+      for (ic = ebbs[i]->sch; ic; ic = ic->next)
+       {
+         
+         if (ic->op == CAST && IC_RESULT (ic) && IS_ITEMP (IC_RESULT (ic)))
+           {
+             type1 = operandType (IC_RIGHT (ic));
+             type2 = operandType (IC_RESULT (ic));
+
+             /* Look only for a cast from an integer type to an */
+             /* integer type that has no loss of bits */
+             if (!IS_INTEGRAL (type1) || !IS_INTEGRAL (type2))
+               continue;
+             if (getSize (type2) < getSize (type1))
+               continue;
+             
+             /* There must be only one use of this first result */
+             if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) != 1)
+               continue;
+             
+             /* This use must be a second cast */
+             uic = hTabItemWithKey (iCodehTab,
+                       bitVectFirstBit (OP_USES (IC_RESULT (ic))));
+             if (!uic || uic->op != CAST)
+               continue;
+  
+             /* It must be a cast to another integer type that */
+             /* has no loss of bits */
+             type3 = operandType (IC_RESULT (uic));
+             if (!IS_INTEGRAL (type3))
+                continue;
+             if (getSize (type3) < getSize (type2))
+                continue;
+             
+             /* The signedness between the first and last types */
+             /* must match */
+             if (SPEC_USIGN (type3) != SPEC_USIGN (type1))
+                continue;
+
+             /* Change the first cast to a simple assignment and */
+             /* let the second cast do all the work */
+             ic->op = '=';
+             IC_LEFT (ic) = NULL;
+             sym = OP_SYMBOL (IC_RESULT (ic));
+             sym->type = copyLinkChain (type1);
+             sym->etype = getSpec (sym->type);
+           }
+       }
+    }
+}
+
 /*-----------------------------------------------------------------*/
 /* eBBlockFromiCode - creates extended basic blocks from iCode     */
 /*                    will return an array of eBBlock pointers     */
@@ -779,6 +1184,12 @@ eBBlockFromiCode (iCode * ic)
   ebbs = iCodeBreakDown (ic, &count);
   saveCount = count;
 
+  /* hash the iCode keys so that we can quickly index */
+  /* them in the rest of the optimization steps */
+  setToNull ((void *) &iCodehTab);
+  iCodehTab = newHashTable (iCodeKey);
+  hashiCodeKeys (ebbs, count);
+  
   /* compute the control flow */
   computeControlFlow (ebbs, count, 0);
 
@@ -799,8 +1210,10 @@ eBBlockFromiCode (iCode * ic)
   if (options.dump_raw)
     dumpEbbsToFileExt (DUMP_RAW1, ebbs, count);
 
+  optimizeCastCast (ebbs, saveCount);
+    
   /* do common subexpression elimination for each block */
-  change = cseAllBlocks (ebbs, saveCount);
+  change = cseAllBlocks (ebbs, saveCount, FALSE);
 
   /* dumpraw if asked for */
   if (options.dump_raw)
@@ -816,10 +1229,15 @@ eBBlockFromiCode (iCode * ic)
   /* global common subexpression elimination  */
   if (optimize.global_cse)
     {
-      change += cseAllBlocks (ebbs, saveCount);
+      change += cseAllBlocks (ebbs, saveCount, FALSE);
       if (options.dump_gcse)
        dumpEbbsToFileExt (DUMP_GCSE, ebbs, saveCount);
     }
+  else
+    {
+      // compute the dataflow only
+      assert(cseAllBlocks (ebbs, saveCount, TRUE)==0);
+    }
   /* kill dead code */
   kchange = killDeadCode (ebbs, saveCount);
 
@@ -841,7 +1259,7 @@ eBBlockFromiCode (iCode * ic)
   if (lchange || kchange)
     {
       computeDataFlow (ebbs, saveCount);
-      change += cseAllBlocks (ebbs, saveCount);
+      change += cseAllBlocks (ebbs, saveCount, FALSE);
       if (options.dump_loop)
        dumpEbbsToFileExt (DUMP_LOOPG, ebbs, count);
 
@@ -859,18 +1277,36 @@ eBBlockFromiCode (iCode * ic)
   /* sort it back by block number */
   qsort (ebbs, saveCount, sizeof (eBBlock *), bbNumCompare);
 
+  if (!options.lessPedantic) {
+    // this is a good place to check missing return values
+    if (currFunc) {
+      // the user is on his own with naked functions...
+      if (!IS_VOID(currFunc->etype)
+       && !FUNC_ISNAKED(currFunc->type)) {
+       eBBlock *bp;
+       // make sure all predecessors of the last block end in a return
+       for (bp=setFirstItem(ebbs[saveCount-1]->predList); 
+            bp; 
+            bp=setNextItem(ebbs[saveCount-1]->predList)) {
+         if (bp->ech->op != RETURN) {
+           werrorfl (bp->ech->filename, bp->ech->lineno,
+                     W_VOID_FUNC, currFunc->name);
+         }
+       }
+      }
+    }
+  }
+
   /* if cyclomatic info requested then print it */
   if (options.cyclomatic)
     printCyclomatic (ebbs, saveCount);
 
-
   /* convert operations with support routines
      written in C to function calls : Iam doing
      this at this point since I want all the
      operations to be as they are for optimzations */
   convertToFcall (ebbs, count);
 
-
   /* compute the live ranges */
   computeLiveRanges (ebbs, count);
 
@@ -886,10 +1322,9 @@ eBBlockFromiCode (iCode * ic)
   port->assignRegisters (ebbs, count);
 
   /* throw away blocks */
-  setToNull ((void **) &graphEdges);
+  setToNull ((void *) &graphEdges);
   ebbs = NULL;
-
-
+  
   return NULL;
 }