[gcc r13-4989] generic-match-head: Don't assume GENERIC folding is done only early [PR108237]

[gcc r13-4989] generic-match-head: Don't assume GENERIC folding is done only early [PR108237]

[Jakub Jelinek]

https://gcc.gnu.org/g:345dffd0d4ebff7e705dfff1a8a72017a167120a

commit r13-4989-g345dffd0d4ebff7e705dfff1a8a72017a167120a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Jan 4 10:54:38 2023 +0100

    generic-match-head: Don't assume GENERIC folding is done only early [PR108237]
    
    We ICE on the following testcase, because a valid V2DImode
    != comparison is folded into an unsupported V2DImode > comparison.
    The match.pd pattern which does this looks like:
    /* Transform comparisons of the form (X & Y) CMP 0 to X CMP2 Z
       where ~Y + 1 == pow2 and Z = ~Y.  */
    (for cst (VECTOR_CST INTEGER_CST)
     (for cmp (eq ne)
          icmp (le gt)
      (simplify
       (cmp (bit_and:c@2 @0 cst@1) integer_zerop)
        (with { tree csts = bitmask_inv_cst_vector_p (@1); }
         (if (csts && (VECTOR_TYPE_P (TREE_TYPE (@1)) || single_use (@2)))
          (with { auto optab = VECTOR_TYPE_P (TREE_TYPE (@1))
                             ? optab_vector : optab_default;
                  tree utype = unsigned_type_for (TREE_TYPE (@1)); }
           (if (target_supports_op_p (utype, icmp, optab)
                || (optimize_vectors_before_lowering_p ()
                    && (!target_supports_op_p (type, cmp, optab)
                        || !target_supports_op_p (type, BIT_AND_EXPR, optab))))
            (if (TYPE_UNSIGNED (TREE_TYPE (@1)))
             (icmp @0 { csts; })
             (icmp (view_convert:utype @0) { csts; })))))))))
    and that optimize_vectors_before_lowering_p () guarded stuff there
    already deals with this problem, not trying to fold a supported comparison
    into a non-supported one.  The reason it doesn't work in this case is that
    it isn't GIMPLE folding which does this, but GENERIC folding done during
    forwprop4 - forward_propagate_into_comparison -> forward_propagate_into_comparison_1
    -> combine_cond_expr_cond -> fold_binary_loc -> generic_simplify
    and we simply assumed that GENERIC folding happens only before
    gimplification.
    
    The following patch fixes that by checking cfun properties instead of
    always returning true in those cases.
    
    2023-01-04  Jakub Jelinek  <jakub@redhat.com>
    
            PR middle-end/108237
            * generic-match-head.cc: Include tree-pass.h.
            (canonicalize_math_p, optimize_vectors_before_lowering_p): Define
            to false if cfun and cfun->curr_properties has PROP_gimple_opt_math
            resp. PROP_gimple_lvec property set.
    
            * gcc.c-torture/compile/pr108237.c: New test.

Diff:
---
 gcc/generic-match-head.cc                      |  5 +++--
 gcc/testsuite/gcc.c-torture/compile/pr108237.c | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc
index a3672bf7341..f011204c5be 100644
--- a/gcc/generic-match-head.cc
+++ b/gcc/generic-match-head.cc
@@ -40,6 +40,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tm.h"
 #include "tree-eh.h"
 #include "langhooks.h"
+#include "tree-pass.h"
 
 /* Routine to determine if the types T1 and T2 are effectively
    the same for GENERIC.  If T1 or T2 is not a type, the test
@@ -71,7 +72,7 @@ single_use (tree t ATTRIBUTE_UNUSED)
 static inline bool
 canonicalize_math_p ()
 {
-  return true;
+  return !cfun || (cfun->curr_properties & PROP_gimple_opt_math) == 0;
 }
 
 /* Return true if math operations that are beneficial only after
@@ -90,7 +91,7 @@ canonicalize_math_after_vectorization_p ()
 static inline bool
 optimize_vectors_before_lowering_p ()
 {
-  return true;
+  return !cfun || (cfun->curr_properties & PROP_gimple_lvec) == 0;
 }
 
 /* Return true if successive divisions can be optimized.
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr108237.c b/gcc/testsuite/gcc.c-torture/compile/pr108237.c
new file mode 100644
index 00000000000..52b7f9d177f
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr108237.c
@@ -0,0 +1,14 @@
+/* PR middle-end/108237 */
+
+typedef unsigned char __attribute__((__vector_size__ (1))) U;
+typedef unsigned long long __attribute__((__vector_size__ (16))) V;
+
+U u;
+V v;
+
+V
+foo (void)
+{
+  V w = v != ((unsigned char) ((unsigned char) u == u) & v);
+  return w;
+}