tests/codegen/target-feature-inline-closure.rs is flaky

[ehuss]

The tests/codegen/target-feature-inline-closure.rs test has been failing randomly in CI.

The problem is that it is searching for the string fadd, which can appear in hex strings.

#116591 attempted to fix it, but that only helped with comparing the rustc version hash. It still fails if the characters fadd appear in a symbol hash. For example:

---- [codegen] tests/codegen/target-feature-inline-closure.rs stdout ----

error: verification with 'FileCheck' failed
status: exit status: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/ci-llvm/bin/FileCheck" "--input-file" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen/target-feature-inline-closure/target-feature-inline-closure.ll" "/checkout/tests/codegen/target-feature-inline-closure.rs" "--allow-unused-prefixes" "--check-prefixes" "CHECK,NONMSVC" "--dump-input-context" "100"
stdout: none
--- stderr -------------------------------
Build completed unsuccessfully in 0:33:57
/checkout/tests/codegen/target-feature-inline-closure.rs:27:16: error: CHECK-NOT: excluded string found in input
 // CHECK-NOT: fadd
               ^
/checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen/target-feature-inline-closure/target-feature-inline-closure.ll:35:74: note: found here
 call fastcc void @_ZN4core9core_arch3x863avx13_mm256_add_ps17hc86357fdcefaddcdE(ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %_0, ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %1, ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %0)
                                                                         ^~~~

Input file: /checkout/obj/build/x86_64-unknown-linux-gnu/test/codegen/target-feature-inline-closure/target-feature-inline-closure.ll
Check file: /checkout/tests/codegen/target-feature-inline-closure.rs

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

Input was:
<<<<<<
        1: ; ModuleID = 'target_feature_inline_closure.5b935a73a363356c-cgu.0' 
        2: source_filename = "target_feature_inline_closure.5b935a73a363356c-cgu.0" 
        3: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" 
        4: target triple = "x86_64-unknown-linux-gnu" 
        5:  
        6: ; core::core_arch::x86::avx::_mm256_add_ps 
        7: ; Function Attrs: inlinehint mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable 
        8: define internal fastcc void @_ZN4core9core_arch3x863avx13_mm256_add_ps17hc86357fdcefaddcdE(ptr noalias nocapture noundef writeonly align 32 dereferenceable(32) %_0, ptr noalias nocapture noundef readonly align 32 dereferenceable(32) %a, ptr noalias nocapture noundef readonly align 32 dereferenceable(32) %b) unnamed_addr #0 { 
        9: start: 
       10:  %0 = load <8 x float>, ptr %a, align 32 
       11:  %1 = load <8 x float>, ptr %b, align 32 
       12:  %2 = fadd <8 x float> %0, %1 
       13:  store <8 x float> %2, ptr %_0, align 32 
       14:  ret void 
       15: } 
       16:  
       17: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable 
       18: define void @with_avx(ptr noalias nocapture noundef writeonly sret(<8 x float>) align 32 dereferenceable(32) %_0, ptr noalias nocapture noundef readonly align 32 dereferenceable(32) %x) unnamed_addr #1 { 
       19: start: 
       20:  %0 = load <8 x float>, ptr %x, align 32 
       21:  %1 = fadd <8 x float> %0, %0 
       22:  store <8 x float> %1, ptr %_0, align 32 
       23:  ret void 
       24: } 
       25:  
       26: ; Function Attrs: mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable 
       27: define void @without_avx(ptr noalias nocapture noundef writeonly sret(<8 x float>) align 32 dereferenceable(32) %_0, ptr noalias nocapture noundef readonly align 32 dereferenceable(32) %x) unnamed_addr #2 { 
       28: start: 
       29:  %0 = alloca <8 x float>, align 32 
       30:  %1 = alloca <8 x float>, align 32 
       31:  %2 = load <8 x float>, ptr %x, align 32 
       32:  store <8 x float> %2, ptr %1, align 32 
       33:  store <8 x float> %2, ptr %0, align 32 
       34: ; call core::core_arch::x86::avx::_mm256_add_ps 
       35:  call fastcc void @_ZN4core9core_arch3x863avx13_mm256_add_ps17hc86357fdcefaddcdE(ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %_0, ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %1, ptr noalias nocapture noundef nonnull align 32 dereferenceable(32) %0) 
not:27                                                                              !~~~                                                                                                                                                                                                                           error: no match expected
       36:  ret void 
       37: } 
       38:  
       39: attributes #0 = { inlinehint mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" "target-features"="+avx" } 
       40: attributes #1 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" "target-features"="+avx" } 
       41: attributes #2 = { mustprogress nofree norecurse nosync nounwind nonlazybind willreturn memory(argmem: readwrite) uwtable "probe-stack"="inline-asm" "target-cpu"="x86-64" } 
       42:  
       43: !llvm.module.flags = !{!0, !1} 
       44: !llvm.ident = !{!2} 
       45:  
       46: !0 = !{i32 8, !"PIC Level", i32 2} 
       47: !1 = !{i32 2, !"RtLibUseGOT", i32 1} 
       48: !2 = !{!"rustc version 1.75.0 (e61a83a28 2023-10-18)"} 
>>>>>>
------------------------------------------

[Zalathar]

If hashes are the recurring problem, it may be possible to write something like:

// CHECK: {{ fadd }}
...
// CHECK-NOT: {{ fadd }}

Or perhaps:

// CHECK: {{\b}}fadd{{\b}}
...
// CHECK-NOT: {{\b}}fadd{{\b}}