<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/77462>77462</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            LLVM ERROR: Instruction Combining did not reach a fixpoint after 1 iterations
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          TatyanaDoubts
      </td>
    </tr>
</table>

<pre>
    FuzzGen generated test failed with the error above.

run opt with -passes=instcombine
https://godbolt.org/z/9n5djc1Mh
There is an entry https://github.com/llvm/llvm-project/issues/65107, but it seems below is more interesting testcase.

Test.ll
```
; ModuleID = 'gen_00017'
source_filename = "gen_00017"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: write)
declare void @llvm.assume(i1 noundef) #1

define i1 @function_0(i64 %val_i64_10, i16 %val_i16_17) {
entry_1:
  %val_i1_47 = trunc i64 %val_i64_10 to i1
 %val_i64_64 = zext i1 %val_i1_47 to i64
  br label %prhdr_loop_5

bb_3:                                             ; preds = %loop_6, %bb_3
  %struct_val_i64_71 = cmpxchg ptr null, i64 0, i64 %val_i64_64 syncscope("singlethread") monotonic monotonic, align 8
  br i1 false, label %bb_3, label %prhdr_loop_5

prhdr_loop_5: ; preds = %bb_3, %entry_1
  %val_i32_74 = trunc i64 %val_i64_64 to i32
  %val_i1_76 = trunc i32 %val_i32_74 to i1
  call void @llvm.assume(i1 %val_i1_47)
  br label %loop_6

loop_6: ; preds = %be_8, %prhdr_loop_5
  br i1 %val_i1_47, label %be_8, label %bb_3

be_8: ; preds = %loop_6
  call void @llvm.assume(i1 %val_i1_76)
  br label %loop_6
}
```
Stack dump:
```
0.      Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/opt -o /app/output.s -S -passes instcombine <source>
 #0 0x00000000035a87a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x35a87a8)
 #1 0x00000000035a5efc SignalHandler(int) Signals.cpp:0:0
 #2 0x00007f93f4042520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x00007f93f40969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x00007f93f4042476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x00007f93f40287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x0000000000790ecd llvm::json::operator==(llvm::json::Value const&, llvm::json::Value const&) (.cold) JSON.cpp:0:0
 #7 0x000000000315b551 combineInstructionsOverFunction(llvm::Function&, llvm::InstructionWorklist&, llvm::AAResults*, llvm::AssumptionCache&, llvm::TargetLibraryInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::OptimizationRemarkEmitter&, llvm::BlockFrequencyInfo*, llvm::ProfileSummaryInfo*, llvm::LoopInfo*, llvm::InstCombineOptions const&) (.isra.0) InstructionCombining.cpp:0:0
 #8 0x000000000315bbcb llvm::InstCombinePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x315bbcb)
 #9 0x00000000037afbfe llvm::detail::PassModel<llvm::Function, llvm::InstCombinePass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x37afbfe)
#10 0x0000000000d8763d llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0xd8763d)
#11 0x0000000002f456fe llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x2f456fe)
#12 0x0000000000d6b97e llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0xd6b97e)
#13 0x0000000002f436ac llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x2f436ac)
#14 0x000000000089673a llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x89673a)
#15 0x000000000079cd53 main (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x79cd53)
#16 0x00007f93f4029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#17 0x00007f93f4029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#18 0x000000000088b98e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x88b98e)
Program terminated with signal: SIGSEGV
Compiler returned: 139
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkWVtzmzwa_jXKjcYeEOcLX7hx3e1us-kkme4lI-AFqxESK4kc-ut3JLANjvNt0i8Xe_A4MUjv8XkfnYBqzRoBsELRJxRtLmhvdlKt7qh5poJuZF8YfVHI6nm17X_9-gICNyBAUQMVNqANrinjUOFHZnbY7ACDUlJhWsgHWCJvg7z18F_1AsvODIKLjmoNGgUbJrQpZVswAYPczphOo2CNyBaRbSOrQnKzlKpBZPsLkW0moupn6V_tBvG7HSjATGMqMAijnvGJAWZ2fbEsZYvIlvOH_c-iU_InlAaRLdO6B43INo58L0HkEhe9wcxgDdBqXACXj9ZDK60nYUCBNkw0Lv-S6nmed6DNkvOxKfbG73AbfMJXsuo5fN1gFGwwIkkDIvc8z08QSQYpLXtVQl4zDoK2MAqSiSAZBA1VDRhcUUM5fZa92YvCokXBGhYsDlGwjsNFnXooWPskXYjUXsQoWAdk6Lv1SXpq0ijW8YPnpzTO43DRi3shH8WCM9E_LRrRH7SO2W17URomBV4bo2wVsJAl5byg5T0WslYAWEj9LEosZC8embDU4VyB6ZXALbRSPSOSMkHLErRmBYcWbDb4UTEDiGSDswpKThXgB8kqjELP1nRJte5bsOq-M19BjUiGEQn8aaAV1EwAZr5VrMeIc8_qxSFGJHqgPGdxmPueZQPz40OjH-e2ABlGyafBmCNd7lvCuXt8lM3DxEFoVC9K_MI2NhKzMbBpj5ULNvgXPBkX49ScVYnDvadCYU4L4FamU7tK5VzKLo-myRZFHlj43vOxlewUVHpkQOTMxhYMRCJn8ZirNqovTb6PPvGdUtl2T-WuwZ1RWPScOyDjEHv7i3nClhG6lJ0tHiJEM9FwMDsFtLIsIxlupZBGClYer6wpylkjcDpBhPm4plyD7T2g42KeNrwG16w9WL-EYm8JkWhf-pO6ByRPwtcLH4euigF5yZcknqoF5MTklC_YjqrX2T8lzWHMzAkz1nSS-9hyNmvI0zHrl8jtYZ87naI_as_LMSWpFTjndxrk23NO4rfknGzOTtK3xs5VVd92hzF9IuEtkZd9V7JRtMVUNX0LwrjJDpGt7OyaUsq2YxzUAp46LhUo28apaBZ24VN2wtELW-d7RLYFE4MiXkhrgnadve9N15ulxovb_XqJJ6slRsHlsFKg4PNhEgk87D15-08Q0TShKXbrXrBGwVo_6-Hiu2LCuFTvFC0tgkchRR9zqY0C2iLiRj0TZphI0z-ZISKfvKcxrGON7AR9EncEdYlvWSMo_wsVFbf20zGMoVkvy86WyHN_B0NkNJTUWVCHXkgi4o2Bc1Ygsh1Xs8kqZjvKpZbL2IXnVGbBBXObWZzVJe6G6Sm_Z5y_z4HTnzkIT4MOkxg32uX53uDDKfsRCaK5bZImdWD3Z8q8z7JTnFmOpzXzksyDsppw7aeWYriSnd0xSoWCjf1OuXYU-kF5D7iUQpuRdW-RcqRclpJX9vqvt9d_P0-LZMYvPyqiyMfjUPoqhjXMUvb6AdR-EzML9Nh4EttE-x9S3XN2Jv71-gZ0z41GZH3SYyewzipf0nIHLzTv3IbsGysUVc9fRS1fkbhTVOhaqvaszEa2TNgK3Cl46eO6M6xlv6iN4gZaqu4_t8wYO-ROJD9xWd5vFfyzB1GO4Zwk9F1Ju3O97dv2EPGJyDcpu7MdFsrLoSbXDhP9otJMK7q0oxNPcB90mGjO1z49rX1RFue9fqd6nB9V_8byrwXlz5rpKypoAwoFl2eUgs_HFD5kBh2SmI3GbJZlQuuihkmcFRjK-FgjqvWVrICfj_a1mjh0TooNGtQDVAMKoH8PG_v9LwB9wPQAul21ZsutV6VJHFQfALqT_aPcfhfm_9_qDbWZFW-25yB1GMWzETOc1O_kPiRblHVFO7eQnUt4UHhXuqPKRyc7JjPLlsypGhdZ8r75YZ_e5Rsx-iiuHTF6jWn_OcAPsM5wD05YFsS0fMNQP4f2_wpKIwozmMIZPdMsTgI6iVL1jlvfWQecifl55dYoJpobqM9x85X90hUtd87O-t_st762HX8pJSW_duezLeNnjPyp7lfSWStFn23rtEAOE943TLyY3WVnciPlOKQHf39jovojqR-gWM1A7eUK2_Pu3w_jycCCGU2ikzNHWUUBbikTH-VzMDnzGZ-coLIqe-eR0qnMbCanNiH0cJ5btVwbqkw-SerNXiCce0nngyotshTwYP_DauSMHrzuH4sYUO7IsX81MJxlUbDGt1-_3H7-8mMQvxwd4-EBMFRWwg-yk-cuF9UqqLIgoxew8hMvTL3Ij7OL3SqLAvAzj0JBw7AMC0KDFIIsKaLaAxKmF2xFPBJ6vpf5JMpIugyToKIQ12EVJaQgPgo9aCnjS_c8Sarmwr0PWCVJGJML9-RIu5cjhAh4xK4TEYKizYVauTcJRd9oFHr24KePVgwzHFbfvv24wp9vbq5vbGKTIws-nFlwxSospMEKaLnDFNfsqZNMGExrAwr7mBl7fLY1uOgVX_3-Cw6X078CAAD__-Qn4n8">