Remove transfer insns if possible

git-svn-id: svn://svn.cc65.org/cc65/trunk@795 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/src/cc65/coptind.c b/src/cc65/coptind.c
index 4fbad2bbcc8628791da27e805e2a149e25919a20..0987d37db61ebc4c129d24e9b53ed5f0f4557473 100644 (file)
--- a/src/cc65/coptind.c
+++ b/src/cc65/coptind.c
@@ -681,7 +681,8 @@ unsigned OptDuplicateLoads (CodeSeg* S)
     while (I < CS_GetEntryCount (S)) {
 
        unsigned char Use, Chg;
-
+       CodeEntry* N;
+                                    
        /* Get next entry */
                CodeEntry* E = CS_GetEntry (S, I);
 
@@ -858,7 +859,7 @@ unsigned OptDuplicateLoads (CodeSeg* S)
 
            case OP65_LDA:
                if (IsKnownImm (E)) {
-                   CodeEntry* N = CS_GetNextEntry (S, I);
+                   N = CS_GetNextEntry (S, I);
                    if (RegA >= 0 && RegA == E->Num && N && (N->Info & OF_FBRA) == 0) {
                        Delete = 1;
                    } else {
@@ -872,7 +873,7 @@ unsigned OptDuplicateLoads (CodeSeg* S)
 
            case OP65_LDX:
                if (IsKnownImm (E)) {
-                   CodeEntry* N = CS_GetNextEntry (S, I);
+                   N = CS_GetNextEntry (S, I);
                            if (RegX >= 0 && RegX == E->Num && N && (N->Info & OF_FBRA) == 0) {
                        Delete = 1;
                    } else {
@@ -886,7 +887,7 @@ unsigned OptDuplicateLoads (CodeSeg* S)
 
            case OP65_LDY:
                if (IsKnownImm (E)) {
-                   CodeEntry* N = CS_GetNextEntry (S, I);
+                   N = CS_GetNextEntry (S, I);
                            if (RegY >= 0 && RegY == E->Num && N && (N->Info & OF_FBRA) == 0) {
                        Delete = 1;
                    } else {
@@ -1001,11 +1002,23 @@ unsigned OptDuplicateLoads (CodeSeg* S)
                break;
 
            case OP65_TAX:
-               RegX = RegA;
+               N = CS_GetNextEntry (S, I);
+               if (RegA >= 0 && RegA == RegX && N && (N->Info & OF_FBRA) == 0) {
+                   /* Value is identical and not followed by a branch */
+                   Delete = 1;
+               } else {
+                   RegX = RegA;
+               }
                break;
 
            case OP65_TAY:
-               RegY = RegA;
+               N = CS_GetNextEntry (S, I);
+                       if (RegA >= 0 && RegA == RegY && N && (N->Info & OF_FBRA) == 0) {
+                   /* Value is identical and not followed by a branch */
+                   Delete = 1;
+               } else {
+                   RegY = RegA;
+               }
                break;
 
            case OP65_TRB:
@@ -1019,14 +1032,26 @@ unsigned OptDuplicateLoads (CodeSeg* S)
                break;
 
            case OP65_TXA:
-               RegA = RegX;
+               N = CS_GetNextEntry (S, I);
+                       if (RegX >= 0 && RegX == RegA && N && (N->Info & OF_FBRA) == 0) {
+                   /* Value is identical and not followed by a branch */
+                   Delete = 1;
+               } else {
+                   RegA = RegX;
+               }
                break;
 
            case OP65_TXS:
                break;
 
            case OP65_TYA:
-               RegA = RegY;
+               N = CS_GetNextEntry (S, I);
+                       if (RegY >= 0 && RegY == RegA && N && (N->Info & OF_FBRA) == 0) {
+                   /* Value is identical and not followed by a branch */
+                   Delete = 1;
+               } else {
+                   RegA = RegY;
+               }
                break;
 
            default: