llvmpasses: force vector width for compatibility with non-x86 hosts.

[maleadt]

The pipeline-prints test currently fails when running on an aarch64-macos device:

/Users/tim/Julia/src/julia/test/llvmpasses/pipeline-prints.ll:309:23: error: AFTERVECTORIZATION: expected string not found in input
; AFTERVECTORIZATION: vector.body
                      ^
<stdin>:2:40: note: scanning from here
; *** IR Dump Before AfterVectorizationMarkerPass on julia_f_199 ***
                                       ^
<stdin>:47:27: note: possible intended match here
; *** IR Dump Before AfterVectorizationMarkerPass on jfptr_f_200 ***
                          ^

Input file: <stdin>
Check file: /Users/tim/Julia/src/julia/test/llvmpasses/pipeline-prints.ll

-dump-input=help explains the following input dump.

Input was:
<<<<<<
             1: opt: WARNING: failed to create target machine for 'x86_64-unknown-linux-gnu': unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
             2: ; *** IR Dump Before AfterVectorizationMarkerPass on julia_f_199 ***
check:309'0                                            X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
             3: define i64 @julia_f_199(ptr addrspace(10) noundef nonnull align 16 dereferenceable(40) %0) #0 !dbg !4 {
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             4: top:
check:309'0     ~~~~~
             5:  %1 = call ptr @julia.get_pgcstack()
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             6:  %ptls_field = getelementptr inbounds ptr, ptr %1, i64 2
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             7:  %ptls_load45 = load ptr, ptr %ptls_field, align 8, !tbaa !8
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             .
             .
             .
            42:
check:309'0     ~
            43: L41: ; preds = %L41.loopexit, %L17, %top
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            44:  %value_phi10 = phi i64 [ 0, %top ], [ %7, %L17 ], [ %.lcssa, %L41.loopexit ]
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            45:  ret i64 %value_phi10, !dbg !52
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            46: }
check:309'0     ~~
            47: ; *** IR Dump Before AfterVectorizationMarkerPass on jfptr_f_200 ***
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:309'1                               ?                                           possible intended match
            48: ; Function Attrs: noinline optnone
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            49: define nonnull ptr addrspace(10) @jfptr_f_200(ptr addrspace(10) %0, ptr noalias nocapture noundef readonly %1, i32 %2) #1 {
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            50: top:
check:309'0     ~~~~~
            51:  %3 = call ptr @julia.get_pgcstack()
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            52:  %4 = getelementptr inbounds ptr addrspace(10), ptr %1, i32 0
check:309'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
             .
             .
             .
>>>>>>

--

********************
Failed Tests (1):
  Julia :: pipeline-prints.ll

The problem is that these tests assume x86_64, which fails because the target isn't available, so it presumably uses the native target which has different vectorization characteristics:

❯ ./usr/tools/opt --load-pass-plugin=libjulia-codegen.dylib -passes='julia' --print-before=AfterVectorization -o /dev/null ../../test/llvmpasses/pipeline-prints.ll
./usr/tools/opt: WARNING: failed to create target machine for 'x86_64-unknown-linux-gnu': unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.

There's other tests that assume this (e.g. the fma cpufeatures one), but they don't fail, so I've left them as is.

[vchuravy]

./usr/tools/opt: WARNING: failed to create target machine for 'x86_64-unknown-linux-gnu': unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.

So this is yet again us not properly building our version of LLVM as a cross-compiler.

In #56188 I noticed that one might be able to use -force-vector-width=2 & co to have portable tests.

[maleadt]

-force-vector-width=2

TIL; and that works too. Let me update the PR.