From: Vibhav Pant <vibhavp@gmail.com>
Date: Tue, 4 Oct 2022 19:31:50 +0000 (+0530)
Subject: Add comment explaining gcc_jit_context_new_bitcast usage.
X-Git-Tag: emacs-29.0.90~1856^2~9
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=219cbccb9ac1d25df5534b60c0c6a6071b2303ed;p=emacs.git

Add comment explaining gcc_jit_context_new_bitcast usage.
---

diff --git a/src/comp.c b/src/comp.c
index 794501f11b0..b7541c5d9f7 100644
--- a/src/comp.c
+++ b/src/comp.c
@@ -1179,6 +1179,11 @@ emit_coerce (gcc_jit_type *new_type, gcc_jit_rvalue *obj)
 
   gcc_jit_rvalue *tmp = obj;
 
+  /* `gcc_jit_context_new_bitcast` requires that the types being converted
+     between have the same layout and as such, doesn't allow converting
+     between an arbitrarily sized integer/boolean and a pointer. Casting it
+     to a uintptr/void* is still necessary, to ensure that it can be bitcast
+     into a (void *)/uintptr respectively.  */
   if (old_is_ptr != new_is_ptr)
     {
       if (old_is_ptr)