对于你第一个程序，我用的编译器的编译信息如下，不过我的PICC 9.65是没有激活的，只能用于Lite模式，不能对代码进行优化。

Build E:PIC_projectsc_test est for device 16F877A
Using driver D:Program FilesHI-TECH SoftwarePICCPRO9.65inpicc.exe

Make: The target "E:PIC_projectsc_test est.p1" is out of date.
Executing: "D:Program FilesHI-TECH SoftwarePICCPRO9.65inpicc.exe" --pass1 E:PIC_projectsc_test est.c -q --chip=16F877A -P --runtime=default --opt=default -D__DEBUG=1 -g --asmlist "--errformat=Error   [%n] %f; %l.%c %s" "--msgformat=Advisory[%n] %s" "--warnformat=Warning [%n] %f; %l.%c %s"
Executing: "D:Program FilesHI-TECH SoftwarePICCPRO9.65inpicc.exe" -otest.cof -mtest.map --summary=default --output=default test.p1 --chip=16F877A -P --runtime=default --opt=default -D__DEBUG=1 -g --asmlist "--errformat=Error   [%n] %f; %l.%c %s" "--msgformat=Advisory[%n] %s" "--warnformat=Warning [%n] %f; %l.%c %s"
HI-TECH C PRO for the PIC10/12/16 MCU family (Lite)  V9.65PL1
Copyright (C) 1984-2009 HI-TECH SOFTWARE
(1273) Omniscient Code Generation not available in Lite mode (warning)

Memory Summary:
    Program space        used    1Ah (    26) of  2000h words   (  0.3%)
    Data space           used     4h (     4) of   170h bytes   (  1.1%)
    EEPROM space         used     0h (     0) of   100h bytes   (  0.0%)
    Configuration bits   used     1h (     1) of     1h word    (100.0%)
    ID Location space    used     0h (     0) of     4h bytes   (  0.0%)

Running this compiler in PRO mode, with Omniscient Code Generation enabled,
produces code which is typically 52% smaller than in Lite mode.
The HI-TECH C PRO compiler output for this code could be 13 words smaller.
See http://microchip.htsoft.com/portal/pic_pro for more information.

Loaded E:PIC_projectsc_test est.cof.

********** Build successful! **********


并没有你所说的警告信息。
而且可以创建变量……见下图：


(原文件名:picc.jpg)