[LLVMdev] Question About the LLVM IR unnamed values!

[Jin Huang]

Hi.

I found that, in all the LLVM IR I get from the source C file.  the unnamed
values all created by the "load" instruction. eg:



; Function Attrs: nounwind uwtable
define i32 @add(i32 %x, i32 %y) #0 {
entry:
  %x.addr = alloca i32, align 4
  %y.addr = alloca i32, align 4
  %c = alloca i32, align 4
  store i32 %x, i32* %x.addr, align 4
  store i32 %y, i32* %y.addr, align 4
*  %0 = load i32* %x.addr, align 4*
*  %1 = load i32* %y.addr, align 4*
  %add = add nsw i32 %0, %1
  store i32 %add, i32* %c, align 4
  %2 = load i32* %c, align 4
  ret i32 %2
}

; Function Attrs: nounwind uwtable
define i32 @main() #0 {
entry:
  %retval = alloca i32, align 4
  %a = alloca i32, align 4
  %b = alloca i32, align 4
  %d = alloca i32, align 4
  %f = alloca i32, align 4
  %g = alloca i32, align 4
  %e = alloca i32, align 4
  store i32 0, i32* %retval
  store i32 8, i32* %a, align 4
  store i32 9, i32* %b, align 4
 * %0 = load i32* %a, align 4*
*  %1 = load i32* %b, align 4*
  %add = add nsw i32 %0, %1
  store i32 %add, i32* %d, align 4
*  %2 = load i32* %a, align 4*
*  %3 = load i32* %d, align 4*
  %add1 = add nsw i32 %2, %3
  store i32 %add1, i32* %f, align 4
*  %4 = load i32* %f, align 4*
*  %5 = load i32* %b, align 4*
  %add2 = add nsw i32 %4, %5
  store i32 %add2, i32* %g, align 4
*  %6 = load i32* %d, align 4*
*  %7 = load i32* %b, align 4*
  %call = call i32 @add(i32 %6, i32 %7)
  store i32 %call, i32* %e, align 4
  %call3 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str, i32 0, i32 0), i32* %a)
  %call4 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str1, i32 0, i32 0), i32* %b)
  %call5 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str2, i32 0, i32 0), i32* %e)
  %call6 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str, i32 0, i32 0), i32* %d)
  %call7 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str, i32 0, i32 0), i32* %g)
  %call8 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x
i8]* @.str, i32 0, i32 0), i32* %f)
  ret i32 0
}
​
the "add" instructions all have names like "%add", "%add1",etc.But the
"load" instruction all use "%n". ​

​is that means the unnamed instructions like "%0 %1" all created by the
"load" instructions? ​is there any other type instructions can create
unnamed values?

Thanks!


-- 
Kind Regards!
-Jin Huang
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