Re: [patch] Fix PR tree-optimization/70884

[Eric Botcazou <ebotcazou@adacore.com>]

> Hmm, the patch looks obvious if it was the intent to allow constant
> pool replacements
> _not_ only when the whole constant pool entry may go away.  But I
> think the intent was
> to not do this otherwise it will generate worse code by forcing all
> loads from the constant pool to appear at
> function start.

Do you mean when the whole constant pool entry is scalarized as opposed to 
partially scalarized?

> So - the "real" issue may be a missing
> should_scalarize_away_bitmap/cannot_scalarize_away_bitmap
> check somewhere.

This seems to work:

Index: tree-sra.c
===================================================================
--- tree-sra.c  (revision 236195)
+++ tree-sra.c  (working copy)
@@ -2680,6 +2680,10 @@ analyze_all_variable_accesses (void)
   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
     {
       tree var = candidate (i);
+      if (constant_decl_p (var)
+         && (!bitmap_bit_p (should_scalarize_away_bitmap, i)
+             || bitmap_bit_p (cannot_scalarize_away_bitmap, i)))
+       continue;
       struct access *access;
 
       access = sort_and_splice_var_accesses (var);

but I have no idea whether this is correct or not.


Martin, are we sure to disable scalarization of constant_decl_p variables not 
covered by initialize_constant_pool_replacements that way?

-- 
Eric Botcazou