From 5591f1109b45a482bdaea3d3e44a80212a188edd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny@quansight.com>
Date: Mon, 28 Jul 2025 21:33:18 +0200
Subject: [PATCH 1/2] BLD: provide explicit control over cpu-baseline detection
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Add a new `cpu-baseline-detect` feature flag that can be used to more
precisely control the use of CPU baseline detection.  This can be used
by packages to more precisely control used SIMD code independently
of compiler flags specified.  The option follows typical feature
semantics -- with `auto` preserving the current behavior of enabling
when relevant compiler flags are found, `enabled` forcing it on
based on the implicit compiler defaults, and `disabled` forcing it off.

Signed-off-by: Michał Górny <mgorny@quansight.com>
---
 meson.options         |  2 ++
 meson_cpu/meson.build | 22 ++++++++++++----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/meson.options b/meson.options
index b09992fe9b91..f17f9901664a 100644
--- a/meson.options
+++ b/meson.options
@@ -28,6 +28,8 @@ option('disable-optimization', type: 'boolean', value: false,
         description: 'Disable CPU optimized code (dispatch,simd,unroll...)')
 option('cpu-baseline', type: 'string', value: 'min',
         description: 'Minimal set of required CPU features')
+option('cpu-baseline-detect', type: 'feature', value: 'auto',
+        description: 'Detect CPU baseline from the compiler flags')
 option('cpu-dispatch', type: 'string', value: 'max -xop -fma4',
         description: 'Dispatched set of additional CPU features')
 option('test-simd', type: 'array',
diff --git a/meson_cpu/meson.build b/meson_cpu/meson.build
index e5b6d0fbe7be..1c4c6eecb308 100644
--- a/meson_cpu/meson.build
+++ b/meson_cpu/meson.build
@@ -46,20 +46,22 @@ if get_option('disable-optimization')
   CPU_CONF_BASELINE = 'none'
   CPU_CONF_DISPATCH = 'none'
 else
-  baseline_detect = false
+  baseline_detect = get_option('cpu-baseline-detect').enabled()
   c_args = get_option('c_args')
-  foreach arg : c_args
-    foreach carch : ['-march', '-mcpu', '-xhost', '/QxHost']
-      if arg.contains(carch)
-        message('Appending option "detect" to "cpu-baseline" due to detecting global architecture c_arg "' + arg + '"')
-        baseline_detect = true
+  if get_option('cpu-baseline-detect').auto()
+    foreach arg : c_args
+      foreach carch : ['-march', '-mcpu', '-xhost', '/QxHost']
+        if arg.contains(carch)
+          message('Appending option "detect" to "cpu-baseline" due to detecting global architecture c_arg "' + arg + '"')
+          baseline_detect = true
+          break
+        endif
+      endforeach
+      if baseline_detect
         break
       endif
     endforeach
-    if baseline_detect
-      break
-    endif
-  endforeach
+  endif
   # The required minimal set of required CPU features.
   CPU_CONF_BASELINE = get_option('cpu-baseline')
   if baseline_detect