codegen-units=1, debug=true, varying lto

lto = "fat"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	2:31	90.8207MiB	7.3374MiB
["-Z", "gcc-ld=lld"]	2:31	91.9731MiB	7.3332MiB
linker = "clang"	2:32	90.8207MiB	7.3375MiB
linker = "clang"; fuse-ld="mold"	2:31	92.1107MiB	7.3334MiB

lto = "thin"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	1:33	96.9630MiB	8.1695MiB
["-Z", "gcc-ld=lld"]	1:32	98.3889MiB	8.1777MiB
linker = "clang"	1:33	96.9631MiB	8.1695MiB
linker = "clang"; fuse-ld="mold"	1:32	98.6903MiB	8.1797MiB

lto = false

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	1:32	113.5656MiB	8.0601MiB
["-Z", "gcc-ld=lld"]	1:30	115.1210MiB	8.1122MiB
linker = "clang"	1:32	113.5656MiB	8.0602MiB
linker = "clang"; fuse-ld="mold"	1:31	115.4679MiB	8.0663MiB

lto = "off"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	1:33	113.5666MiB	8.0601MiB
["-Z", "gcc-ld=lld"]	1:31	115.1231MiB	8.1122MiB
linker = "clang"	1:32	113.5667MiB	8.0602MiB
linker = "clang"; fuse-ld="mold"	1:31	115.4697MiB	8.0662MiB

codegen-units=8, debug=true, varying lto

lto = "fat"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	2:21	104.9842MiB	7.6304MiB
["-Z", "gcc-ld=lld"]	2:19	106.1436MiB	7.6264MiB
linker = "clang"	2:21	104.9882MiB	7.6344MiB
linker = "clang"; fuse-ld="mold"	2:19	106.2864MiB	7.6325MiB

lto = "thin"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	1:12	134.1112MiB	9.0445MiB
["-Z", "gcc-ld=lld"]	1:09	136.1897MiB	9.0660MiB
linker = "clang"	1:12	134.1113MiB	9.0446MiB
linker = "clang"; fuse-ld="mold"	1:09	136.4466MiB	9.0494MiB

lto = false

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	1:14	158.1049MiB	9.0328MiB
["-Z", "gcc-ld=lld"]	1:11	159.9998MiB	9.1129MiB
linker = "clang"	1:14	158.1050MiB	9.0328MiB
linker = "clang"; fuse-ld="mold"	1:12	160.3123MiB	9.0428MiB

lto = "off"

Flags	Clean build time	Pre-strip size	Post-strip size
(default)	0:57	145.9463MiB	9.4586MiB
["-Z", "gcc-ld=lld"]	0:54	148.6021MiB	9.6001MiB
linker = "clang"	0:57	145.9464MiB	9.4587MiB
linker = "clang"; fuse-ld="mold"	0:55	148.8842MiB	9.4668MiB

---

mold appears to be similar but not faster than lld.

With the caveat that this is not a proper benchmark since:

• I didn’t measure link time alone.
• I didn’t bother running each case multiple times picking the fastest run (since I perceived the differences to be insignificant).

And a side note, lto = false appears to be practically useless.