Default build: disable-native?

[jodavies]

Due to the issue of #704 cropping up (again), I wonder if it makes sense to not enable march native for the default build? Actually on my system (AMD Zen4) I would tentatively suggest that it makes tform ~1% slower?

test	default/--disable-native
trace	1.02 ± 0.02
mincer	1.02 ± 0.00
minceex	1.00 ± 0.00
mass-fact	1.02 ± 0.00
forcer	1.01 ± 0.00
forcer-exp	1.01 ± 0.01
mbox1l	0.98 ± 0.03
color	1.02 ± 0.01
chromatic	1.00 ± 0.00

[tueda]

Somehow, I got similar results... -march=native is slower than the default (-march=x86_64 or something like that)??
(CPU=16, Alder Lake, gcc-15.2, flint-3.3.1 (configure option: --host=$(gcc -dumpmachine)), Ubuntu 25.04 on Docker; host: Ubuntu 20.04):

Running trace Benchmark 1: /form/build/sources/tform Time (mean ± σ): 1.402 s ± 0.064 s [User: 21.222 s, System: 0.192 s] Range (min … max): 1.249 s … 1.537 s 60 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 1.372 s ± 0.076 s [User: 20.730 s, System: 0.192 s] Range (min … max): 1.222 s … 1.539 s 60 runs Summary /form/build-disable-native/sources/tform ran 1.02 ± 0.07 times faster than /form/build/sources/tform Running minceex Benchmark 1: /form/build/sources/tform Time (mean ± σ): 48.559 s ± 0.266 s [User: 539.331 s, System: 1.533 s] Range (min … max): 48.065 s … 48.992 s 12 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 47.921 s ± 0.198 s [User: 532.118 s, System: 1.544 s] Range (min … max): 47.668 s … 48.420 s 12 runs Summary /form/build-disable-native/sources/tform ran 1.01 ± 0.01 times faster than /form/build/sources/tform Running forcer Benchmark 1: /form/build/sources/tform Time (mean ± σ): 163.715 s ± 1.036 s [User: 826.400 s, System: 20.714 s] Range (min … max): 162.511 s … 165.165 s 6 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 163.140 s ± 0.758 s [User: 831.020 s, System: 20.810 s] Range (min … max): 162.092 s … 164.003 s 6 runs Summary /form/build-disable-native/sources/tform ran 1.00 ± 0.01 times faster than /form/build/sources/tform Running forcer-exp Benchmark 1: /form/build/sources/tform Time (mean ± σ): 87.863 s ± 0.540 s [User: 553.178 s, System: 19.795 s] Range (min … max): 86.800 s … 88.742 s 8 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 86.217 s ± 0.542 s [User: 549.549 s, System: 20.428 s] Range (min … max): 85.342 s … 87.199 s 8 runs Summary /form/build-disable-native/sources/tform ran 1.02 ± 0.01 times faster than /form/build/sources/tform Running mbox1l Benchmark 1: /form/build/sources/tform Time (mean ± σ): 12.944 s ± 0.260 s [User: 82.939 s, System: 0.543 s] Range (min … max): 12.495 s … 13.542 s 30 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 12.869 s ± 0.309 s [User: 83.262 s, System: 0.520 s] Range (min … max): 12.070 s … 13.437 s 30 runs Summary /form/build-disable-native/sources/tform ran 1.01 ± 0.03 times faster than /form/build/sources/tform Running color Benchmark 1: /form/build/sources/tform Time (mean ± σ): 11.961 s ± 0.261 s [User: 139.446 s, System: 1.493 s] Range (min … max): 11.465 s … 12.678 s 30 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 11.526 s ± 0.232 s [User: 134.363 s, System: 1.464 s] Range (min … max): 11.166 s … 12.183 s 30 runs Summary /form/build-disable-native/sources/tform ran 1.04 ± 0.03 times faster than /form/build/sources/tform Running chromatic Benchmark 1: /form/build/sources/tform Time (mean ± σ): 80.767 s ± 0.654 s [User: 813.736 s, System: 2.251 s] Range (min … max): 79.928 s … 81.815 s 8 runs Benchmark 2: /form/build-disable-native/sources/tform Time (mean ± σ): 79.725 s ± 0.328 s [User: 829.202 s, System: 2.260 s] Range (min … max): 79.281 s … 80.105 s 8 runs Summary /form/build-disable-native/sources/tform ran 1.01 ± 0.01 times faster than /form/build/sources/tform