Question on scalar replacement

[Richard Kenner]

I'm compiling the Ada RTS file a-colire.adb.

In .t32.sra, I see 

Scalar replacements:
T.47.P_BOUNDS -> SR.196
FRAME.64.M12b -> SR.198
T.47.P_ARRAY -> SR.195

The first and last seem OK, but there is no assignment to SR.198 in the
.t32 file but instead, the assignment

<L10>:;
  FRAME.64.M12b = system__secondary_stack__ss_mark ();

from the .t31 file is still present.

There is no documenation in the front of tree-sra.c (again, I thought that
such documentation was supposed to be a required criteria for the tree-ssa
merge), so I can't know what exactly what this optimization is doing wrong.

What should I be looking at?

Also, when is the missing documentation supposed to be added?