Re: inserting prefetch instructions in ssa

["Daniel Berlin" <dberlin at dberlin dot org>]

On 4/4/07, George Caragea <george@cs.umd.edu> wrote:
> Hi all,
> I've been trying to add a pass in GCC 4.0.2 which is targeted for a
> MIPS-like architecture (with small changes). The purpose of the pass is
> to add prefetch instructions for some array references.
>
> After I identify a MODIFY_EXPR which is a read from an array location,
> I'm having trouble getting gcc to insert a prefetch instruction for it.
> I've been trying to follow the same pattern as in
> tree-ssa-loop-prefetch.c, which I got from the gcc-svn version. However,
> it doesn't work, and Im not sure if it's because of the differences in
> versions, or because I'm doing something wrong.
>
> The output I get when I compile a program is:
> ===
> In force_gimple_operand_bsi, inserting statements: D.1109_4 = &B[i_8];
> The prefetch instr generated is: __builtin_prefetch (D.1109_4, 0);
> done inserting
> XMTS.simple32.c:6: internal compiler error: tree check: expected
> ssa_name, have var_decl in verify_ssa, at tree-ssa.c:679

You need to mark these variables for renaming.
In 4.3 you'd just use mark_new_vars_for_renaming.
I don't remember what you use in 4.0 (in general, it is never a good
idea to do new work against anything but the development version of
gcc)