Merge remote-tracking branch 'origin/master' into llvm13

Conflicts:

 * cmake/Findclang.cmake
 * cmake/Findlld.cmake
 * cmake/Findllvm.cmake

In master branch, more search paths were added to these files with "12"
in the path. In this commit I updated them to "13".

 * src/stage1/codegen.cpp
 * src/zig_llvm.cpp
 * src/zig_llvm.h

In master branch, ZigLLVMBuildCmpXchg is improved to add
`is_single_threaded`. However, the LLVM 13 C API has this already, and
in the llvm13 branch, ZigLLVMBuildCmpXchg is deleted in favor of the C
API. In this commit I updated stage2 to use the LLVM 13 C API rather
than depending on an improved ZigLLVMBuildCmpXchg.

Additionally, src/target.zig largestAtomicBits needed to be updated to
include the new m68k ISA.

1 files changed, 70 insertions, 0 deletions

diff --git a/src/target.zig b/src/target.zig
index 6f50c8d5e9..4f9898cfa8 100644
--- a/src/target.zig
+++ b/src/target.zig
@@ -480,3 +480,73 @@ pub fn clangAssemblerSupportsMcpuArg(target: std.Target) bool {
 pub fn needUnwindTables(target: std.Target) bool {
     return target.os.tag == .windows;
 }
+
+/// TODO this was ported from stage1 but it does not take into account CPU features,
+/// which can affect this value. Audit this!
+pub fn largestAtomicBits(target: std.Target) u32 {
+    return switch (target.cpu.arch) {
+        .avr,
+        .msp430,
+        .spu_2,
+        => 16,
+
+        .arc,
+        .arm,
+        .armeb,
+        .hexagon,
+        .m68k,
+        .le32,
+        .mips,
+        .mipsel,
+        .nvptx,
+        .powerpc,
+        .powerpcle,
+        .r600,
+        .riscv32,
+        .sparc,
+        .sparcel,
+        .tce,
+        .tcele,
+        .thumb,
+        .thumbeb,
+        .i386,
+        .xcore,
+        .amdil,
+        .hsail,
+        .spir,
+        .kalimba,
+        .lanai,
+        .shave,
+        .wasm32,
+        .renderscript32,
+        .csky,
+        .spirv32,
+        => 32,
+
+        .aarch64,
+        .aarch64_be,
+        .aarch64_32,
+        .amdgcn,
+        .bpfel,
+        .bpfeb,
+        .le64,
+        .mips64,
+        .mips64el,
+        .nvptx64,
+        .powerpc64,
+        .powerpc64le,
+        .riscv64,
+        .sparcv9,
+        .s390x,
+        .amdil64,
+        .hsail64,
+        .spir64,
+        .wasm64,
+        .renderscript64,
+        .ve,
+        .spirv64,
+        => 64,
+
+        .x86_64 => 128,
+    };
+}