[tree-ssa] bootstrap comparison failure on ppc and ppc64

[Andrew MacLeod]

On Tue, 2003-07-29 at 07:52, Diego Novillo wrote:
> 
> Jeff, Andrew,
> 
> One of these three patches is causing a comparison failure on ppc and
> ppc64.  I'm going to try Andrew's fix from this morning to see if it has
> any effect.
> 
> 

I dont think any of these changes actually turn on the PHI as constant
code, so neither my patch nor most of these *ought* to affect anything
:-). Famous last words eh :-)

The likely things I see that affect code are you disabling must-alias
and the change to move_outgoing_edges.  

Im sure glad my big patch last night wasn't in this list :-)

Andrew

> Diego.
> 
> --- gcc.prev/gcc/ChangeLog.tree-ssa     2003-07-28 00:04:32.000000000 -0400
> +++ gcc/gcc/ChangeLog.tree-ssa  2003-07-29 00:05:38.000000000 -0400
> @@ -1,3 +1,34 @@
> +2003-07-28  Diego Novillo  <dnovillo@redhat.com>
> +
> +       * opts.c (decode_options): Disable must-alias optimization.
> +
> +2003-07-28  Andrew MacLeod  <amacleod@redhat.com>
> +
> +       * tree-ssa.c (struct _elim_graph): Add varray for constant copies.
> +       (new_elim_graph): Initialize constant copy array..
> +       (eliminate_build): Push constant copies onto stack instead of emitting.
> +       (eliminate_phi): Emit any pending constant copies.
> +
> +2003-07-28  Jeff Law  <law@redhat.com>
> +
> +       * tree-ssa-dom.c (optimize_block): If a PHI has a single argument
> +       that is a constant, then that creates a useful equivalence.
> +       Propagate constant values into PHI nodes.
> +
> +       * tree-flow-inline.h (may_propagate_copy): Allow RHS to be a
> +       constant.
> +
> +       * tree-dfa.c (compute_immediate_uses_for): Do not assume that
> +       PHI arguments are SSA_NAMEs.
> +       * tree-ssa-dce.c (process_worklist): Likewise.
> +       * tree-ssa-copyprop.c (copyprop_phi): Likewise.  Use may_propagate_copy.
> +       * tree-ssa-ccp.c (visit_phi_node): Do not assume that PHI arguments
> +       are SSA_NAMEs.  Create a suitable value if a PHI argument is a
> +       constant.
> +
> +       * tree-cfg.c (move_outgoing_edges): Correctly handle case where
> +       an edge already exists from BB1 to BB2's successor.
> +
>