[DAG] Add SDPatternMatch m_SpecificScalarVT / m_SpecificVectorElementVT matchers

[RKSimon]

We already have m_SpecificVT(EVT) which matches a specific requested value type, these helpers would be similar but would match the scalar/vector element component type:

• Add SDPatternMatch::m_SpecificScalarVT matcher to match a source SDValue getScalarType result (i.e. either a scalar type or vector element element type)
• Add SDPattcrnMatch::m_SpecificVectorElementVT matcher to check a source SDValue type is a vector and match its getVectorElementType result
• Unit test coverage in SelectionDAGPatternMatchTest.cpp

[zhaohuiw42]

Hi, I’d like to work on this issue. Could you please assign it to me?

[llvmbot]

Hi!

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[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Simon Pilgrim (RKSimon)

We already have m_SpecificVT(EVT) which matches a specific requested value type, these helpers would be similar but would match the scalar/vector element component type:

• Add SDPatternMatch::m_SpecificScalarVT matcher to match a source SDValue getScalarType result (i.e. either a scalar type or vector element element type)
• Add SDPattcrnMatch::m_SpecificVectorElementVT matcher to check a source SDValue type is a vector and match its getVectorElementType result
• Unit test coverage in SelectionDAGPatternMatchTest.cpp