backengineering · gmh5225 · Aug 2, 2026 · Aug 2, 2026 · Aug 2, 2026
diff --git a/.github/workflows/issue176-regression.yml b/.github/workflows/issue176-regression.yml
@@ -0,0 +1,232 @@
+name: issue176-regression
+
+permissions:
+  actions: read
+  contents: read
+
+on:
+  workflow_run:
+    workflows:
+      - windows-llvm-msvc-build
+      - android-llvm-msvc-build
+    types: [completed]
+  workflow_dispatch:
+    inputs:
+      commit:
+        description: 'Commit SHA to test (defaults to the triggering ref)'
+        required: false
+      platform:
+        description: 'Which platform artifacts to test'
+        type: choice
+        options:
+          - all
+          - windows
+          - linux
+        default: all
+
+concurrency:
+  group: issue176-regression-${{ github.event.workflow_run.head_sha || github.sha }}-${{ github.event_name }}
+  cancel-in-progress: true
+
+jobs:
+  plan:
+    if: >
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'workflow_run' &&
+       github.event.workflow_run.conclusion == 'success')
+    runs-on: ubuntu-latest
+    outputs:
+      commit: ${{ steps.plan.outputs.commit }}
+      run_windows: ${{ steps.plan.outputs.run_windows }}
+      run_linux: ${{ steps.plan.outputs.run_linux }}
+      windows_run_id: ${{ steps.plan.outputs.windows_run_id }}
+      linux_run_id: ${{ steps.plan.outputs.linux_run_id }}
+    steps:
+      - name: Plan verification jobs
+        id: plan
+        env:
+          EVENT_NAME: ${{ github.event_name }}
+          WORKFLOW_NAME: ${{ github.event.workflow_run.name || '' }}
+          WORKFLOW_RUN_ID: ${{ github.event.workflow_run.id || '' }}
+          HEAD_SHA: ${{ github.event.workflow_run.head_sha || github.sha }}
+          INPUT_COMMIT: ${{ github.event.inputs.commit || '' }}
+          INPUT_PLATFORM: ${{ github.event.inputs.platform || 'all' }}
+        run: |
+          set -euo pipefail
+
+          commit="$HEAD_SHA"
+          if [ "$EVENT_NAME" = "workflow_dispatch" ] && [ -n "$INPUT_COMMIT" ]; then
+            commit="$INPUT_COMMIT"
+          fi
+
+          run_windows=false
+          run_linux=false
+          windows_run_id=
+          linux_run_id=
+
+          if [ "$EVENT_NAME" = "workflow_run" ]; then
+            case "$WORKFLOW_NAME" in
+              windows-llvm-msvc-build)
+                run_windows=true
+                windows_run_id="$WORKFLOW_RUN_ID"
+                ;;
+              android-llvm-msvc-build)
+                run_linux=true
+                linux_run_id="$WORKFLOW_RUN_ID"
+                ;;
+            esac
+          else
+            case "$INPUT_PLATFORM" in
+              all)
+                run_windows=true
+                run_linux=true
+                ;;
+              windows) run_windows=true ;;
+              linux) run_linux=true ;;
+            esac
+          fi
+
+          {
+            echo "commit=$commit"
+            echo "run_windows=$run_windows"
+            echo "run_linux=$run_linux"
+            echo "windows_run_id=$windows_run_id"
+            echo "linux_run_id=$linux_run_id"
+          } >> "$GITHUB_OUTPUT"
+
+  find-windows-run:
+    needs: plan
+    if: needs.plan.outputs.run_windows == 'true'
+    runs-on: ubuntu-latest
+    outputs:
+      run_id: ${{ steps.find.outputs.run_id }}
+    steps:
+      - name: Resolve Windows build run id
+        id: find
+        uses: actions/github-script@v7
+        env:
+          COMMIT: ${{ needs.plan.outputs.commit }}
+          RUN_ID: ${{ needs.plan.outputs.windows_run_id }}
+        with:
+          script: |
+            if (process.env.RUN_ID) {
+              core.setOutput('run_id', process.env.RUN_ID);
+              return;
+            }
+            const commit = process.env.COMMIT;
+            const { data } = await github.rest.actions.listWorkflowRuns({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              workflow_id: 'windows-llvm-msvc-build.yml',
+              head_sha: commit,
+              status: 'success',
+              per_page: 5,
+            });
+            const run = data.workflow_runs.find(r => r.conclusion === 'success');
+            if (!run) {
+              core.setFailed(`No successful windows-llvm-msvc-build run for ${commit}`);
+              return;
+            }
+            core.setOutput('run_id', String(run.id));
+
+  find-linux-run:
+    needs: plan
+    if: needs.plan.outputs.run_linux == 'true'
+    runs-on: ubuntu-latest
+    outputs:
+      run_id: ${{ steps.find.outputs.run_id }}
+    steps:
+      - name: Resolve Linux build run id
+        id: find
+        uses: actions/github-script@v7
+        env:
+          COMMIT: ${{ needs.plan.outputs.commit }}
+          RUN_ID: ${{ needs.plan.outputs.linux_run_id }}
+        with:
+          script: |
+            if (process.env.RUN_ID) {
+              core.setOutput('run_id', process.env.RUN_ID);
+              return;
+            }
+            const commit = process.env.COMMIT;
+            const { data } = await github.rest.actions.listWorkflowRuns({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              workflow_id: 'android-llvm-msvc-build.yml',
+              head_sha: commit,
+              status: 'success',
+              per_page: 5,
+            });
+            const run = data.workflow_runs.find(r => r.conclusion === 'success');
+            if (!run) {
+              core.setFailed(`No successful android-llvm-msvc-build run for ${commit}`);
+              return;
+            }
+            core.setOutput('run_id', String(run.id));
+
+  test-windows:
+    needs: [plan, find-windows-run]
+    if: needs.plan.outputs.run_windows == 'true'
+    runs-on: windows-2022
+    steps:
+      - name: Checkout test inputs
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.plan.outputs.commit }}
+
+      - name: Download Windows PR build artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: windows-llvm-msvc
+          run-id: ${{ needs.find-windows-run.outputs.run_id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          path: artifacts/windows
+
+      - name: Extract install prefix
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          Set-Location artifacts/windows
+          $first = Get-ChildItem -Filter 'windows-llvm-msvc.zip.*' | Sort-Object Name | Select-Object -First 1
+          if (-not $first) { throw 'windows-llvm-msvc zip parts not found' }
+          7z x $first.Name
+
+      - name: Verify issue #176 on Windows binary
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          & .github/workflows/scripts/verify-issue176.ps1 `
+            -InstallPrefix "$PWD/artifacts/windows/install" `
+            -RepoRoot "$PWD"
+
+  test-linux:
+    needs: [plan, find-linux-run]
+    if: needs.plan.outputs.run_linux == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout test inputs
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ needs.plan.outputs.commit }}
+
+      - name: Install 7z
+        run: sudo apt-get update && sudo apt-get install -y p7zip-full
+
+      - name: Download Linux PR build artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: android-llvm-msvc
+          run-id: ${{ needs.find-linux-run.outputs.run_id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          path: artifacts/linux
+
+      - name: Extract install prefix
+        run: |
+          set -euo pipefail
+          cd artifacts/linux
+          7z x android-llvm-msvc.zip
+
+      - name: Verify issue #176 on Linux binary
+        run: |
+          chmod +x .github/workflows/scripts/verify-issue176.sh
+          .github/workflows/scripts/verify-issue176.sh "$PWD/artifacts/linux/install" "$PWD"
diff --git a/.github/workflows/scripts/verify-issue176.ps1 b/.github/workflows/scripts/verify-issue176.ps1
@@ -0,0 +1,66 @@
+# Regression checks for llvm-msvc issue #176 (32-bit Linux ISel crash).
+param(
+  [Parameter(Mandatory = $true)][string]$InstallPrefix,
+  [Parameter(Mandatory = $true)][string]$RepoRoot
+)
+
+$ErrorActionPreference = 'Stop'
+
+$Bin = Join-Path $InstallPrefix 'bin'
+$Clang = Join-Path $Bin 'clang++.exe'
+$Llc = Join-Path $Bin 'llc.exe'
+$TestLl = Join-Path $RepoRoot 'llvm\test\CodeGen\X86\issue176-abort-i686-linux.ll'
+
+foreach ($tool in @($Clang, $Llc)) {
+  if (-not (Test-Path $tool)) {
+    throw "Missing tool: $tool"
+  }
+}
+
+if (-not (Test-Path $TestLl)) {
+  throw "Missing test IR: $TestLl"
+}
+
+$Tmp = Join-Path $env:RUNNER_TEMP "issue176-$PID"
+New-Item -ItemType Directory -Path $Tmp -Force | Out-Null
+
+function Run([scriptblock]$Block, [string]$Label) {
+  Write-Host ">>> $Label"
+  & $Block
+  if ($LASTEXITCODE -ne 0) {
+    throw "Command failed: $Label (exit $LASTEXITCODE)"
+  }
+}
+
+Run { & $Clang --version } 'clang++ --version'
+Run { & $Llc --version } 'llc --version'
+
+$Cpp = Join-Path $Tmp 'issue176.cpp'
+$Obj = Join-Path $Tmp 'issue176.o'
+Set-Content -Path $Cpp -Value 'void f() { __builtin_abort(); }' -NoNewline
+
+Run {
+  & $Clang --target=i686-pc-linux-gnu -O1 -c $Cpp -o $Obj
+} 'clang++ i686-linux __builtin_abort @ -O1'
+
+if (-not (Test-Path $Obj) -or (Get-Item $Obj).Length -eq 0) {
+  throw "Object file was not produced: $Obj"
+}
+
+$Triples = @(
+  'i686-pc-linux-gnu',
+  'i686-unknown-linux-gnu',
+  'i686-linux-android'
+)
+
+foreach ($Triple in $Triples) {
+  $Asm = Join-Path $Tmp ("issue176-" + ($Triple -replace '[^a-zA-Z0-9]', '_') + '.s')
+  Run {
+    Get-Content -Raw $TestLl | & $Llc -mtriple=$Triple -relocation-model=pic -o $Asm
+  "llc $Triple"
+  if (-not (Select-String -Path $Asm -Pattern 'calll' -Quiet)) {
+    throw "Expected calll in assembly for $Triple"
+  }
+}
+
+Write-Host 'issue #176 regression checks passed'
diff --git a/.github/workflows/scripts/verify-issue176.sh b/.github/workflows/scripts/verify-issue176.sh
@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+# Regression checks for llvm-msvc issue #176 (32-bit Linux ISel crash).
+set -euo pipefail
+
+INSTALL="${1:?usage: $0 /path/to/install/prefix}"
+REPO="${2:-.}"
+
+BIN="$INSTALL/bin"
+export PATH="$BIN:$PATH"
+
+CLANG="$BIN/clang++"
+LLC="$BIN/llc"
+
+if [[ ! -x "$CLANG" ]]; then
+  echo "clang++ not found under $BIN" >&2
+  exit 1
+fi
+if [[ ! -x "$LLC" ]]; then
+  echo "llc not found under $BIN" >&2
+  exit 1
+fi
+
+TEST_LL="$REPO/llvm/test/CodeGen/X86/issue176-abort-i686-linux.ll"
+if [[ ! -f "$TEST_LL" ]]; then
+  echo "missing test IR: $TEST_LL" >&2
+  exit 1
+fi
+
+TMP="$(mktemp -d)"
+trap 'rm -rf "$TMP"' EXIT
+
+run() {
+  echo ">>> $*"
+  "$@"
+}
+
+echo "=== toolchain ==="
+run "$CLANG" --version
+run "$LLC" --version
+
+echo "=== clang: i686-linux __builtin_abort @ -O1 ==="
+cat >"$TMP/issue176.cpp" <<'EOF'
+void f() { __builtin_abort(); }
+EOF
+run "$CLANG" --target=i686-pc-linux-gnu -O1 -c "$TMP/issue176.cpp" -o "$TMP/issue176.o"
+test -s "$TMP/issue176.o"
+
+echo "=== llc: issue176-abort-i686-linux.ll (3 triples) ==="
+for triple in i686-pc-linux-gnu i686-unknown-linux-gnu i686-linux-android; do
+  echo "--- $triple ---"
+  OUT="$TMP/issue176-${triple//[^a-zA-Z0-9]/_}.s"
+  run "$LLC" <"$TEST_LL" -mtriple="$triple" -relocation-model=pic -o "$OUT"
+  grep -q calll "$OUT"
+done
+
+echo "issue #176 regression checks passed"
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2990,18 +2990,8 @@ bool X86DAGToDAGISel::selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
                                  SDValue &Disp, SDValue &Segment) {
   X86ISelAddressMode AM;
 
-  if (Parent &&
-      // This list of opcodes are all the nodes that have an "addr:$ptr" operand
-      // that are not a MemSDNode, and thus don't have proper addrspace info.
-      Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme
-      Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores
-      Parent->getOpcode() != X86ISD::TLSCALL && // Fixme
-      Parent->getOpcode() != X86ISD::ENQCMD && // Fixme
-      Parent->getOpcode() != X86ISD::ENQCMDS && // Fixme
-      Parent->getOpcode() != X86ISD::EH_SJLJ_SETJMP && // setjmp
-      Parent->getOpcode() != X86ISD::EH_SJLJ_LONGJMP) { // longjmp
-    unsigned AddrSpace =
-      cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
+  if (auto *MemParent = dyn_cast_if_present<MemSDNode>(Parent)) {
+    unsigned AddrSpace = MemParent->getPointerInfo().getAddrSpace();
     if (AddrSpace == X86AS::GS)
       AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
     if (AddrSpace == X86AS::FS)

diff --git a/llvm/test/CodeGen/X86/issue176-abort-i686-linux.ll b/llvm/test/CodeGen/X86/issue176-abort-i686-linux.ll
@@ -0,0 +1,14 @@
+; RUN: llc < %s -mtriple=i686-pc-linux-gnu -relocation-model=pic | FileCheck %s
+; RUN: llc < %s -mtriple=i686-unknown-linux-gnu -relocation-model=pic | FileCheck %s
+; RUN: llc < %s -mtriple=i686-linux-android -relocation-model=pic | FileCheck %s
+
+declare void @abort() nounwind
+
+define void @f() local_unnamed_addr {
+entry:
+  tail call void @abort() nounwind
+  unreachable
+}
+
+; CHECK-LABEL: f:
+; CHECK: calll