python / python/cpython

Simplify `_Py_uop_sym_is_const`

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#133,342 2 comments 0 reactions 1 assignee View on GitHub

@tomasr8 is already working on this.

Since May 8, 2025.

interpreter-core topic-JIT type-feature
Dominant language
Python
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Description

Feature or enhancement

Proposal:

_Py_uop_sym_is_const and _Py_uop_sym_get_const are almost identical. The only difference AFAICS is the return type:

https://github.com/python/cpython/blob/1550c30fd5f2f2902bbcbf64165ae904ebcf7e81/Python/optimizer_symbols.c#L106-L122
https://github.com/python/cpython/blob/1550c30fd5f2f2902bbcbf64165ae904ebcf7e81/Python/optimizer_symbols.c#L131-L148

We could simplify _Py_uop_sym_is_const by calling _Py_uop_sym_get_const and checking if the return is NULL:

diff --git a/Python/optimizer_symbols.c b/Python/optimizer_symbols.c
index e8a4f87031..1f58a3279e 100644
--- a/Python/optimizer_symbols.c
+++ b/Python/optimizer_symbols.c
@@ -106,19 +106,8 @@ _Py_uop_sym_is_not_null(JitOptSymbol *sym) {
 bool
 _Py_uop_sym_is_const(JitOptContext *ctx, JitOptSymbol *sym)
 {
-    if (sym->tag == JIT_SYM_KNOWN_VALUE_TAG) {
-        return true;
-    }
-    if (sym->tag == JIT_SYM_TRUTHINESS_TAG) {
-        JitOptSymbol *value = allocation_base(ctx) + sym->truthiness.value;
-        int truthiness = _Py_uop_sym_truthiness(ctx, value);
-        if (truthiness < 0) {
-            return false;
-        }
-        make_const(sym, (truthiness ^ sym->truthiness.invert) ? Py_True : Py_False);
-        return true;
-    }
-    return false;
+    PyObject *res = _Py_uop_sym_get_const(ctx, sym);
+    return res == NULL ? false : true;
 }
 
 bool
Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs
  • gh-133884

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