diff --git a/src/mesa/shader/arbprogparse.c b/src/mesa/shader/arbprogparse.c
index b306900..10f0a1b 100644
--- a/src/mesa/shader/arbprogparse.c
+++ b/src/mesa/shader/arbprogparse.c
@@ -2691,6 +2691,8 @@
    /* Record the position in the program string for debugging */
    fp->StringPos = Program->Position;
 
+   fp->Data = NULL;
+
    /* OP_ALU_INST or OP_TEX_INST */
    instClass = *(*inst)++;
 
@@ -3113,6 +3115,8 @@
    /* Record the position in the program string for debugging */
    vp->StringPos = Program->Position;
 
+   vp->Data = NULL;
+
    vp->SrcReg[0].RelAddr = vp->SrcReg[1].RelAddr = vp->SrcReg[2].RelAddr = 0;
 
    for (a = 0; a < 4; a++) {
@@ -3706,6 +3710,7 @@
 	 Program->Position = parse_position (&inst);
       */
       Program->FPInstructions[Program->Base.NumInstructions].StringPos = Program->Position;
+      Program->FPInstructions[Program->Base.NumInstructions].Data = NULL;
    }
    else {
       Program->VPInstructions =
@@ -3718,6 +3723,7 @@
 	 Program->Position = parse_position (&inst);
       */
       Program->VPInstructions[Program->Base.NumInstructions].StringPos = Program->Position;
+      Program->VPInstructions[Program->Base.NumInstructions].Data = NULL;
    }
 
    /* increment Program->Base.NumInstructions */