From: sandeep <sandeep@4a8a32a2-be11-0410-ad9d-d568d2c75423>
Date: Mon, 15 Oct 2001 02:03:11 +0000 (+0000)
Subject: A fix for bug #467035 - this is a fairly major shift in
X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=246fcc4a5bdc6d66ae39b4325ad7e9cd1055b15e;p=fw%2Fsdcc

A fix for bug #467035 - this is a fairly major shift in
CSE processing. Previously when an operation was performed
before with the same operands then the result of the previous
operand replaced the result of the current operation entirely.
This was buggy , the current solution looks like a much cleaner
way to do things. Replace the current iCode with the an assignment
of the previous icode's result, we nolonger have to replace the
operands because the assignment exists, will have to watch for
performance regressions


git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@1399 4a8a32a2-be11-0410-ad9d-d568d2c75423
---

diff --git a/src/SDCCcse.c b/src/SDCCcse.c
index f3c27a55..cdc20e1e 100644
--- a/src/SDCCcse.c
+++ b/src/SDCCcse.c
@@ -1513,15 +1513,9 @@ cseBBlock (eBBlock * ebb, int computeOnly,
 	  if (pdic && compareType (operandType (IC_RESULT (pdic)),
 				 operandType (IC_RESULT (ic))) != 1)
 	    pdic = NULL;
-
-	  // TODO: this must go, a weak fix for bug #467035
-	  if (pdic && (pdic->level > ic->level)) {
-	    // pdic was inside an inner loop
-	    pdic = NULL;
-	  }
-	  
 	}
 
+#if 0 
       /* if found then eliminate this and add to */
       /* to cseSet an element containing result */
       /* of this with previous opcode           */
@@ -1578,7 +1572,22 @@ cseBBlock (eBBlock * ebb, int computeOnly,
 	  defic = ic;
 
 	}
+#else
+      /* Alternate code */
+      if (pdic && IS_ITEMP(IC_RESULT(ic))) {
+	  /* if previous definition found change this to an assignment */
+	  ic->op = '=';
+	  IC_RIGHT(ic) = operandFromOperand(IC_RESULT(pdic));
+	  SET_ISADDR(IC_RESULT(ic),0);
+	  SET_ISADDR(IC_RIGHT (ic),0);	  
+      }
 
+      if (!(POINTER_SET (ic)) && IC_RESULT (ic)) {
+	  deleteItemIf (&cseSet, ifDefSymIsX, IC_RESULT (ic));
+	  addSetHead (&cseSet, newCseDef (IC_RESULT (ic), ic));
+      }
+      defic = ic;
+#endif
       /* if assignment to a parameter which is not
          mine and type is a pointer then delete
          pointerGets to take care of aliasing */