[llvm-bugs] [Bug 51133] New: X86 isel crashes when generating AVX code

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https://bugs.llvm.org/show_bug.cgi?id=51133

            Bug ID: 51133
           Summary: X86 isel crashes when generating AVX code
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Common Code Generator Code
          Assignee: unassignedbugs at nondot.org
          Reporter: jeremy.morse.llvm at gmail.com
                CC: andrea.dibiagio at gmail.com, craig.topper at gmail.com,
                    llvm-bugs at lists.llvm.org, llvm-dev at redking.me.uk

Using a recent main (bad3ebbaae3d) build of llc, the following code makes llc
crash in SelectionDAG with arguments `llc reduced.ll -o /dev/null
-mtriple=x86_64-- -mattr=avx`:

define hidden void @_Z1dv() local_unnamed_addr {
entry:
  %call = tail call <32 x i8> undef(<32 x i8> undef, i32 32)
  %rem = srem <32 x i8> %call, <i8 13, i8 5, i8 19, i8 34, i8 2, i8 8, i8 2, i8
88, i8 62, i8 62, i8 5, i8 7, i8 97, i8 2, i8 3, i8 60, i8 3, i8 87, i8 7, i8
6, i8 84, i8 -128, i8 127, i8 56, i8 114, i8 1, i8 50, i8 7, i8 2, i8 8, i8 97,
i8 117>
  %k.0.k.0.k.0. = load volatile <8 x i32>, <8 x i32>* undef, align 32
  %0 = bitcast <8 x i32> %k.0.k.0.k.0. to <32 x i8>
  %cmp = icmp ne <32 x i8> %rem, zeroinitializer
  %cmp4 = icmp ne <32 x i8> %0, zeroinitializer
  %1 = and <32 x i1> %cmp4, %cmp
  %sext = sext <32 x i1> %1 to <32 x i8>
  %call5 = tail call i32 (i8*, ...) undef(i8* poison, <32 x i8> %sext)
  ret void
}

The crash is an assertion failure:

SelectionDAG.cpp:9016: void llvm::SelectionDAG::ReplaceAllUsesWith(llvm::SDNode
*, llvm::SDNode *): Assertion `(!From->hasAnyUseOfValue(i) ||
From->getValueType(i) == To->getValueType(i)) && "Cannot use this version of
ReplaceAllUsesWith!"' failed

It doesn't replicate if you remove -mattr=avx. I have a C reproducer (involving
some intrinsics) of this if that's more useful.

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