Drop support for 32bit x86 linux and windows (#13650)

* Drop support for 32bit x86 linux and windows

Going into Qiskit 2.0 we decided to drop support for windows 32 bit and
linux i686 platforms. Right now the maintainence burden for continuing
to support these platforms is becoming increasingly high, as we're
increasing writing low level rust code to improve performance where we
have to limit ourselves to continue to ensure 32bit platforms work. The
user base for these platforms is quite small small; in the last 150 there
were only 7 downloads for i686 out of 221,992 total downloads from PyPI
(there is no metadata field in PyPI's database to differentiate between
windows 32bit and 64bit if the CPU is 64bit capable it uses AMD64 for
the CPU field), 5 downloads where the CPU type was: "x86" (I'm not sure
which platform uses that string, linux uses x86_64 for 64bit intel, but
i686, i586, i486, etc for 32bit systems), and 35 downloads were armv7l
which is not an official supported platform but is 32bit and you could
build from source (this is typically raspberry pi users). When combining
this with the lack of wider ecosystem support for 32bit platforms,
numpy, scipy, etc all have dropped 32bit support already, keeping support
for 32bit platforms is no longer tenable. This commit updates the
wheel building configuration to drop the 32bit platform builds and adds
a release note documenting the change in status for these platforms in
2.0.

A separate Qiskit/documentation PR will be opened to update our platform
support documentation here:

https://docs.quantum.ibm.com/guides/install-qiskit#operating-system-support

closer to the final 2.0 release to remove the 32bit platforms from the
list. Although we likely should update that page to have a subsection
for 2.x and 1.x while both are supported.

* Update releasenotes/notes/64-bit-only-4132f330ec7804b3.yaml

.github/workflows/wheels-build.yml

@@ -27,15 +27,6 @@ on:
         default: "default"
         required: false
 
-      wheels-32bit:
-        description: >-
-          The action to take for Tier 1 wheels.
-          Choose from 'default', 'build' or 'skip'.
-          This builds multiple artifacts, which all match 'wheels-32bit-*'.
-        type: string
-        default: "default"
-        required: false
-
       wheels-linux-s390x:
         description: >-
           The action to take for Linux s390x wheels.
@@ -133,33 +124,6 @@ jobs:
           path: ./wheelhouse/*.whl
           name: ${{ inputs.artifact-prefix }}wheels-tier-1-${{ matrix.os }}
 
-  wheels-32bit:
-    name: "Wheels / 32bit"
-    if: (inputs.wheels-32bit == 'default' && inputs.default-action || inputs.wheels-32bit) == 'build'
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-          - ubuntu-latest
-          - windows-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: ${{ inputs.python-version }}
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          components: llvm-tools-preview
-      - name: Build wheels
-        uses: pypa/[email protected]
-        env:
-          CIBW_SKIP: 'pp* cp36-* cp37-* cp38-* *musllinux* *amd64 *x86_64'
-      - uses: actions/upload-artifact@v4
-        with:
-          path: ./wheelhouse/*.whl
-          name: ${{ inputs.artifact-prefix }}wheels-32bit-${{ matrix.os }}
-
   wheels-linux-s390x:
     name: "Wheels / Linux s390x"
     if: (inputs.wheels-linux-s390x == 'default' && inputs.default-action || inputs.wheels-linux-s390x) == 'build'

.github/workflows/wheels.yml

@@ -12,7 +12,6 @@ jobs:
       artifact-prefix: "deploy-core-"
       default-action: "skip"
       wheels-tier-1: "build"
-      wheels-32bit: "build"
       sdist: "build"
   upload-core:
     name: Deploy core
@@ -39,7 +38,6 @@ jobs:
       artifact-prefix: "deploy-others-"
       default-action: "build"
       wheels-tier-1: "skip"
-      wheels-32bit: "skip"
       sdist: "skip"
   upload-others:
     name: Deploy other

releasenotes/notes/64-bit-only-4132f330ec7804b3.yaml

@@ -0,0 +1,16 @@
+---
+upgrade:
+  - |
+    Qiskit no longer supports Linux i686 and 32 bit Windows. Starting in Qiskit
+    2.0 a 64 bit platform is needed to run Qiskit. The user base for 32bit
+    architectures is relatively small and as Qiskit continues to focus on
+    improving performance to handle the increased scale in the complexity
+    of quantum computing hardware maintaining support for 32 bit platforms
+    is proving increasingly difficult. This coupled with the larger
+    scientific/numeric Python community's trend away from 32 bit platform
+    support maintaining support for 32bit platforms is no longer viable.
+    Qiskit 1.x will still continue to support 32 bit platforms, but starting
+    in this 2.0.0 release Qiskit no longer supports these platforms, will
+    not publish pre-compiled binaries for these platforms any longer, and
+    there is no longer any guarantee of being able to build from source on
+    32 bit platforms.