[gcc r12-1826] Lower for loops before lowering cond in genmatch

[Andrew Pinski <pinskia@gcc.gnu.org>]

https://gcc.gnu.org/g:2afe882858699bb6c13f8502f4f6e862a126d4ef

commit r12-1826-g2afe882858699bb6c13f8502f4f6e862a126d4ef
Author: Andrew Pinski <apinski@marvell.com>
Date:   Sat Jun 12 18:58:03 2021 -0700

    Lower for loops before lowering cond in genmatch
    
    While converting some fold_cond_expr_with_comparison
    to match, I found that I wanted to use "for cnd (cond vec_cond)"
    but that was not causing the lowering of cond to happen.
    What was happening was the lowering of the for loop
    was happening after the lowering of the cond. So
    swapping was the correct thing to do but it also
    means we need to copy for_subst_vec in lower_cond.
    
    OK?  Bootstrapped and tested on x86_64-linux-gnu with no regressions.
    
    gcc/ChangeLog:
    
            * genmatch.c (lower_cond): Copy for_subst_vec
            for the simplify also.
            (lower): Swap the order for lower_for and lower_cond.

Diff:
---
 gcc/genmatch.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/gcc/genmatch.c b/gcc/genmatch.c
index 4d476720c9e..970a2ebba68 100644
--- a/gcc/genmatch.c
+++ b/gcc/genmatch.c
@@ -1306,6 +1306,7 @@ lower_cond (simplify *s, vec<simplify *>& simplifiers)
     {
       simplify *ns = new simplify (s->kind, s->id, matchers[i], s->result,
 				   s->for_vec, s->capture_ids);
+      ns->for_subst_vec.safe_splice (s->for_subst_vec);
       simplifiers.safe_push (ns);
     }
 }
@@ -1543,24 +1544,27 @@ static void
 lower (vec<simplify *>& simplifiers, bool gimple)
 {
   auto_vec<simplify *> out_simplifiers;
-  for (unsigned i = 0; i < simplifiers.length (); ++i)
-    lower_opt (simplifiers[i], out_simplifiers);
+  for (auto s: simplifiers)
+    lower_opt (s, out_simplifiers);
 
   simplifiers.truncate (0);
-  for (unsigned i = 0; i < out_simplifiers.length (); ++i)
-    lower_commutative (out_simplifiers[i], simplifiers);
+  for (auto s: out_simplifiers)
+    lower_commutative (s, simplifiers);
 
+  /* Lower for needs to happen before lowering cond
+     to support (for cnd (cond vec_cond)).  This is
+     safe as substitution delay does not happen for
+     cond or vec_cond. */
   out_simplifiers.truncate (0);
-  if (gimple)
-    for (unsigned i = 0; i < simplifiers.length (); ++i)
-      lower_cond (simplifiers[i], out_simplifiers);
-  else
-    out_simplifiers.safe_splice (simplifiers);
-
+  for (auto s: simplifiers)
+    lower_for (s, out_simplifiers);
 
   simplifiers.truncate (0);
-  for (unsigned i = 0; i < out_simplifiers.length (); ++i)
-    lower_for (out_simplifiers[i], simplifiers);
+  if (gimple)
+    for (auto s: out_simplifiers)
+      lower_cond (s, simplifiers);
+  else
+    simplifiers.safe_splice (out_simplifiers);
 }