[gcc r14-2040] Bogus and missed folding on vector compares

[Richard Biener]

https://gcc.gnu.org/g:6b32400e19a702137fd11571d199f725add0daf6

commit r14-2040-g6b32400e19a702137fd11571d199f725add0daf6
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jun 23 10:15:27 2023 +0200

    Bogus and missed folding on vector compares
    
    fold_binary tries to transform (double)float1 CMP (double)float2
    into float1 CMP float2 but ends up using TYPE_PRECISION on the
    argument types.  For vector types that compares the number of
    lanes which should be always equal (so it's harmless as to
    not generating wrong code).  The following instead properly
    uses element_precision.
    
    The same happens in the corresponding match.pd pattern.
    
            * fold-const.cc (fold_binary_loc): Use element_precision
            when trying (double)float1 CMP (double)float2 to
            float1 CMP float2 simplification.
            * match.pd: Likewise.

Diff:
---
 gcc/fold-const.cc | 4 ++--
 gcc/match.pd      | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index 3aa6851acd5..b05b3ae16e9 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -12564,10 +12564,10 @@ fold_binary_loc (location_t loc, enum tree_code code, tree type,
 	tree targ1 = strip_float_extensions (arg1);
 	tree newtype = TREE_TYPE (targ0);
 
-	if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype))
+	if (element_precision (TREE_TYPE (targ1)) > element_precision (newtype))
 	  newtype = TREE_TYPE (targ1);
 
-	if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0)))
+	if (element_precision (newtype) < element_precision (TREE_TYPE (arg0)))
 	  return fold_build2_loc (loc, code, type,
 			      fold_convert_loc (loc, newtype, targ0),
 			      fold_convert_loc (loc, newtype, targ1));
diff --git a/gcc/match.pd b/gcc/match.pd
index 2dd23826034..85d562a531d 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6034,10 +6034,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	     type1 = double_type_node;
 	 }
       tree newtype
-        = (TYPE_PRECISION (TREE_TYPE (@00)) > TYPE_PRECISION (type1)
+        = (element_precision (TREE_TYPE (@00)) > element_precision (type1)
 	   ? TREE_TYPE (@00) : type1);
      }
-     (if (TYPE_PRECISION (TREE_TYPE (@0)) > TYPE_PRECISION (newtype))
+     (if (element_precision (TREE_TYPE (@0)) > element_precision (newtype))
       (cmp (convert:newtype @00) (convert:newtype @10))))))))