[LLVMbugs] [Bug 13532] New: Assert on expanded UINT_TO_FP on backends without native f64 support (e.g. Mips and MBlaze)

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=13532

             Bug #: 13532
           Summary: Assert on expanded UINT_TO_FP on backends without
                    native f64 support (e.g. Mips and MBlaze)
           Product: new-bugs
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: stefan.kristiansson at saunalahti.fi
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


This testcase:

$ cat uitofp.ll
define void @f0() nounwind {
entry:
  %b = alloca i32, align 4
  %a = alloca float, align 4
  store volatile i32 1, i32* %b, align 4
  %0 = load volatile i32* %b, align 4
  %conv = uitofp i32 %0 to float
  store float %conv, float* %a, align 4
  ret void
}

$ llc -march=mips -mattr=+single-float uitofp.ll -o -

Will cause the following assert:

llc: /path/to/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1146: void
{anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion
`(TLI.getTypeAction(*DAG.getContext(), Node->getOperand(i).getValueType()) ==
TargetLowering::TypeLegal || Node->getOperand(i).getOpcode() ==
ISD::TargetConstant) && "Unexpected illegal type!"' failed.
Stack dump:
0.      Program arguments: ./bin/llc -mattr=+single-float ../../test/uitofp.ll
1.      Running pass 'Function Pass Manager' on module '../../test/uitofp.ll'.
2.      Running pass 'MIPS DAG->DAG Pattern Instruction Selection' on function
'@f0'
Aborted (core dumped)

The way I understand the thing is that
SelectionDAGLegalize::ExpandLegalINT_TO_FP will insert nodes with
MVT::f64's in them, but this is "too late", since
SelectionDAGLegalize::LegalizeOp expects all the value types to be
natively supported by the target (which is not the case for Mips with MVT::f64
when the +single-float attribute is given).

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