TMS320F2806: Compiler validation for optimization level 4

Please consider this example.

C:\examples>type f1.c
int gets_inlined();

int main()
{
    return gets_inlined();
}

C:\examples>type f2.c
int gets_inlined()
{
    return 0x1234;
}

C:\examples>cl2000 f1.c f2.c -z -o no_opt.out
[f1.c]
[f2.c]
<Linking>

C:\examples>dis2000 no_opt.out > no_opt_dis.txt

The first two commands show the source files.  The third command builds those files into a program.  (Because it uses the linker default memory ranges, it is nearly certain to not run on your system.)  The fourth command disassembles the program into the file no_opt_dis.txt.  Inspect that file and search for the function main ...

00000118        _main:
00000118   7640   LCR          0x00011b
00000119   011b
0000011a   0006   LRETR        
0000011b        _gets_inlined:
0000011b   28a9   MOV          AL, #0x1234
0000011c   1234
0000011d   0006   LRETR        

The LCR instruction performs a call.  The operand is the address of the called function.  In this case, it calls the function gets_inlined at address 0x11b.  The function gets_inlined returns the value 0x1234 in the low half of the accumulator.  

Build again, but with optimization level 4.  Then disassemble into the file opt4_dis.txt.  

C:\examples>cl2000 --opt_level=4 f1.c f2.c -z -o opt4.out
[f1.c]
[f2.c]
<Linking>

C:\examples>dis2000 opt4.out > opt4_dis.txt

Inspect opt4_dis.txt and search for the function main ...

0000010e        _main:
0000010e   28a9   MOV          AL, #0x1234
0000010f   1234
00000110   0006   LRETR 

Now main doesn't call any functions, and it returns the value 0x1234.

Thanks and regards,

-George