[GC] Rework the scan routine to keep the dense cache together. #2460

	name: Run all tests [Ubuntu]
	on: [push, pull_request]

	env:
	LLVM_CONFIG: llvm-config-19

	jobs:
	test:
	name: SDC Tests
	strategy:
	matrix:
	os: [ubuntu-latest]
	dc: [dmd-latest, dmd-beta]

	runs-on: ${{ matrix.os }}

	steps:
	- name: Install system dependencies
	run: sudo apt install nasm lld
	- name: Install D compiler
	uses: dlang-community/setup-dlang@v1
	with:
	compiler: ${{ matrix.dc }}
	- name: Print D version
	run: dmd --version
	- name: Install LLVM
	uses: ZhongRuoyu/setup-llvm@v0
	with:
	llvm-version: 19
	- name: Print LLVM version
	run: ${{ env.LLVM_CONFIG }} --version
	- name: Checkout SDC
	uses: actions/checkout@v2
	# CI runners usually top out at 4 "cores", but things are often busy so -j6 is a happy medium.
	- name: Build
	run: make -j6
	- name: Test
	run: make -j6 check

	sdfmt:
	name: Build sdfmt via dub
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu-latest]
	dc: [dmd-latest, dmd-beta, ldc-latest]
	runs-on: ${{ matrix.os }}
	steps:
	- uses: actions/checkout@v2
	- name: Install D compiler
	uses: dlang-community/setup-dlang@v1
	with:
	compiler: ${{ matrix.dc }}
	- name: Build sdfmt
	run: dub build :sdfmt

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