Re: [PATCH 1/3] Speedup iterative_hash_template_arg

[Jason Merrill]

On 10/2/24 7:49 AM, Richard Biener wrote:

Using iterative_hash_object is expensive compared to using
iterative_hash_hashval_t which is fit for integer sized values.
The following reduces the number of perf cycles spent in
iterative_hash_template_arg and iterative_hash combined by 20%.

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

OK for trunk?

OK.

Thanks,
Richard.

gcc/cp/
        * pt.cc (iterative_hash_template_arg): Avoid using
        iterative_hash_object.
---
  gcc/cp/pt.cc | 6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 43468e5f62e..04f0a1d5fff 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -1751,7 +1751,7 @@ hashval_t
  iterative_hash_template_arg (tree arg, hashval_t val)
  {
    if (arg == NULL_TREE)
-    return iterative_hash_object (arg, val);
+    return iterative_hash_hashval_t (0, val);

if (!TYPE_P (arg))

      /* Strip nop-like things, but not the same as STRIP_NOPS.  */
@@ -1762,7 +1762,7 @@ iterative_hash_template_arg (tree arg, hashval_t val)

enum tree_code code = TREE_CODE (arg); - val = iterative_hash_object (code, val);

+  val = iterative_hash_hashval_t (code, val);

switch (code)

      {
@@ -1777,7 +1777,7 @@ iterative_hash_template_arg (tree arg, hashval_t val)
        return val;

case IDENTIFIER_NODE:

-      return iterative_hash_object (IDENTIFIER_HASH_VALUE (arg), val);
+      return iterative_hash_hashval_t (IDENTIFIER_HASH_VALUE (arg), val);

case TREE_VEC:

        for (tree elt : tree_vec_range (arg))