Revert to simpler (and we hope faster) TAGGEDP

Suggested by Mattias Engdegård (bug#80021#17).
* src/lisp.h (lisp_h_FIXNUMP, lisp_h_TAGGEDP):
Go back to the simpler (X&7) == TAG approach for checking object tags.
This reverses my commit ccdb08ef4ed8f96e79aa06cf5e806c9c487d58ad
“Improve performance of CONSP, FIXNUMP, etc.”
dated 2018-08-25 13:39:18 -0700,
though it keeps the TAGGEDP function the older commit introduced.
Although the older commit improved performance on its circa 2010
platform, when I ran today’s ‘make -C lisp compile-always’
benchmark on Ubuntu 25.10 which uses gcc (Ubuntu 15.2.0-4ubuntu4)
on an circa-2021 Intel Xeon W-1350, this patch makes the
‘make -C lisp compile-always’ benchmark 3.1% faster.  Although the
patch unfortunately also makes the Emacs text segment 0.6% larger,
in this case speed and simplicity beat text size in importance.

1 files changed, 2 insertions, 8 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 968ea4c4086..f278bd32110 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -394,10 +394,7 @@ typedef EMACS_INT Lisp_Word;
 #define lisp_h_CONSP(x) TAGGEDP (x, Lisp_Cons)
 #define lisp_h_BASE_EQ(x, y) (XLI (x) == XLI (y))
 
-#define lisp_h_FIXNUMP(x) \
-   (! (((unsigned) (XLI (x) >> (USE_LSB_TAG ? 0 : FIXNUM_BITS)) \
-        - (unsigned) (Lisp_Int0 >> !USE_LSB_TAG)) \
-       & ((1 << INTTYPEBITS) - 1)))
+#define lisp_h_FIXNUMP(x) ((XTYPE (x) & (Lisp_Int0 | ~Lisp_Int1)) == Lisp_Int0)
 #define lisp_h_FLOATP(x) TAGGEDP (x, Lisp_Float)
 #define lisp_h_NILP(x)  BASE_EQ (x, Qnil)
 #define lisp_h_SYMBOL_CONSTANT_P(sym) \
@@ -405,10 +402,7 @@ typedef EMACS_INT Lisp_Word;
 #define lisp_h_SYMBOL_TRAPPED_WRITE_P(sym) (XSYMBOL (sym)->u.s.trapped_write)
 #define lisp_h_SYMBOL_WITH_POS_P(x) PSEUDOVECTORP (x, PVEC_SYMBOL_WITH_POS)
 #define lisp_h_BARE_SYMBOL_P(x) TAGGEDP (x, Lisp_Symbol)
-#define lisp_h_TAGGEDP(a, tag) \
-   (! (((unsigned) (XLI (a) >> (USE_LSB_TAG ? 0 : VALBITS)) \
-        - (unsigned) (tag)) \
-       & ((1 << GCTYPEBITS) - 1)))
+#define lisp_h_TAGGEDP(a, tag) (XTYPE (a) == (tag))
 #define lisp_h_VECTORLIKEP(x) TAGGEDP (x, Lisp_Vectorlike)
 #define lisp_h_XCAR(c) XCONS (c)->u.s.car
 #define lisp_h_XCDR(c) XCONS (c)->u.s.u.cdr