[PATCH] Fix PR85574

[Richard Biener]

On Thu, 3 Jan 2019, Richard Biener wrote:

> On Thu, 3 Jan 2019, Richard Sandiford wrote:
> 
> > Richard Biener <rguenther@suse.de> writes:
> > > The following rectifies a change during hash-map intruction which
> > > changed the uncprop operand_equal_p based hash to a pointer-based
> > > hash_map.  That assumes pointer equality between constants which
> > > does not hold since different (but compatible) typed constants
> > > can appear in the IL.  For SSA names the equivalence holds, of course.
> > >
> > > Fixing this should increase the number of eliminated const-copies
> > > on edges during out-of-SSA.  It also happens to fix the LTO
> > > bootstrap miscompare of cc1 and friends, but I can't really
> > > explain that.
> > >
> > > [LTO] bootstrapped and tested on x86_64-unknown-linux-gnu, applied
> > > to trunk.
> > >
> > > Richard.
> > >
> > > 2019-01-03  Jan Hubicka  <hubicka@ucw.cz>
> > >
> > > 	PR tree-optimization/85574
> > > 	* tree-ssa-uncprop.c (struct equiv_hash_elt): Remove unused
> > > 	structure.
> > > 	(struct ssa_equip_hash_traits): Declare.
> > > 	(val_ssa_equiv): Use custom hash traits using operand_equal_p.
> > >
> > > Index: gcc/tree-ssa-uncprop.c
> > > ===================================================================
> > > --- gcc/tree-ssa-uncprop.c	(revision 267549)
> > > +++ gcc/tree-ssa-uncprop.c	(working copy)
> > > @@ -268,21 +268,24 @@ associate_equivalences_with_edges (void)
> > >     so with each value we have a list of SSA_NAMEs that have the
> > >     same value.  */
> > >  
> > > -
> > > -/* Main structure for recording equivalences into our hash table.  */
> > > -struct equiv_hash_elt
> > > -{
> > > -  /* The value/key of this entry.  */
> > > -  tree value;
> > > -
> > > -  /* List of SSA_NAMEs which have the same value/key.  */
> > > -  vec<tree> equivalences;
> > > +/* Traits for the hash_map to record the value to SSA name equivalences
> > > +   mapping.  */
> > > +struct ssa_equip_hash_traits : default_hash_traits <tree>
> > > +{
> > > +  static inline hashval_t hash (value_type value)
> > > +    { return iterative_hash_expr (value, 0); }
> > > +  static inline bool equal (value_type existing, value_type candidate)
> > > +    { return operand_equal_p (existing, candidate, 0); }
> > >  };
> > 
> > FWIW, this is a dup of tree_operand_hash.
> 
> Indeed.  Testing patch to do the obvious replacement.

Bootstrapped and tested on x86_64-unknown-linux-gnu.

Richard.

2019-01-07  Richard Biener  <rguenther@suse.de>

	* tree-ssa-uncprop.c (ssa_equip_hash_traits): Remove in favor
	of tree_operand_hash.

Index: gcc/tree-ssa-uncprop.c
===================================================================
--- gcc/tree-ssa-uncprop.c	(revision 267553)
+++ gcc/tree-ssa-uncprop.c	(working copy)
@@ -268,19 +268,7 @@ associate_equivalences_with_edges (void)
    so with each value we have a list of SSA_NAMEs that have the
    same value.  */
 
-/* Traits for the hash_map to record the value to SSA name equivalences
-   mapping.  */
-struct ssa_equip_hash_traits : default_hash_traits <tree>
-{
-  static inline hashval_t hash (value_type value)
-    { return iterative_hash_expr (value, 0); }
-  static inline bool equal (value_type existing, value_type candidate)
-    { return operand_equal_p (existing, candidate, 0); }
-};
-
-typedef hash_map<tree, auto_vec<tree>,
-		 simple_hashmap_traits <ssa_equip_hash_traits,
-					auto_vec <tree> > > val_ssa_equiv_t;
+typedef hash_map<tree_operand_hash, auto_vec<tree> > val_ssa_equiv_t;
 
 /* Global hash table implementing a mapping from invariant values
    to a list of SSA_NAMEs which have the same value.  We might be