Re: [COMMITTED] path solver: Solve PHI imports first for ranges.

[Richard Biener <richard.guenther@gmail.com>]

On November 12, 2021 8:46:25 PM GMT+01:00, Aldy Hernandez via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>PHIs must be resolved first while solving ranges in a block,
>regardless of where they appear in the import bitmap.  We went through
>a similar exercise for the relational code, but missed these.

Must not all stmts be resolved in program order (for optimality at least)? 

>Tested on x86-64 & ppc64le Linux.
>
>gcc/ChangeLog:
>
>	PR tree-optimization/103202
>	* gimple-range-path.cc
>	(path_range_query::compute_ranges_in_block): Solve PHI imports first.
>---
> gcc/gimple-range-path.cc | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
>diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc
>index b9aceaf2565..71b290434cb 100644
>--- a/gcc/gimple-range-path.cc
>+++ b/gcc/gimple-range-path.cc
>@@ -365,12 +365,23 @@ path_range_query::compute_ranges_in_block (basic_block bb)
> 	clear_cache (name);
>     }
> 
>-  // Solve imports defined in this block.
>+  // Solve imports defined in this block, starting with the PHIs...
>+  for (gphi_iterator iter = gsi_start_phis (bb); !gsi_end_p (iter);
>+       gsi_next (&iter))
>+    {
>+      gphi *phi = iter.phi ();
>+      tree name = gimple_phi_result (phi);
>+
>+      if (import_p (name) && range_defined_in_block (r, name, bb))
>+	set_cache (r, name);
>+    }
>+  // ...and then the rest of the imports.
>   EXECUTE_IF_SET_IN_BITMAP (m_imports, 0, i, bi)
>     {
>       tree name = ssa_name (i);
> 
>-      if (range_defined_in_block (r, name, bb))
>+      if (gimple_code (SSA_NAME_DEF_STMT (name)) != GIMPLE_PHI
>+	  && range_defined_in_block (r, name, bb))
> 	set_cache (r, name);
>     }
>