[llvm] [DAG] Add SDPatternMatch m_ZExtOrSelf/m_SExtOrSelf/m_AExtOrSelf/m_TruncOrSelf matchers (PR #85480)

[Marc Auberer via llvm-commits]

https://github.com/marcauberer updated https://github.com/llvm/llvm-project/pull/85480

>From 4367186420552c8f6e3b16d898cdf9d57769a66f Mon Sep 17 00:00:00 2001
From: Marc Auberer <marc.auberer at chillibits.com>
Date: Fri, 15 Mar 2024 23:22:54 +0100
Subject: [PATCH] [DAG] Add SDPatternMatch
 m_ZExtOrSelf/m_SExtOrSelf/m_AExtOrSelf/m_TruncOrSelf matchers

---
 llvm/include/llvm/CodeGen/SDPatternMatch.h    | 33 +++++++++++++++++++
 .../CodeGen/SelectionDAGPatternMatchTest.cpp  | 32 ++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/llvm/include/llvm/CodeGen/SDPatternMatch.h b/llvm/include/llvm/CodeGen/SDPatternMatch.h
index 541c0ecb5be373..45863a1590409b 100644
--- a/llvm/include/llvm/CodeGen/SDPatternMatch.h
+++ b/llvm/include/llvm/CodeGen/SDPatternMatch.h
@@ -737,6 +737,39 @@ template <typename ValTy>
 inline BinaryOpc_match<ValTy, SpecificInt_match, true> m_Not(const ValTy &V) {
   return m_Xor(V, m_AllOnes());
 }
+
+/// Match a zext or identity
+/// Allows to peek through optional extensions
+template <typename Opnd>
+inline Or<UnaryOpc_match<Opnd>, Opnd> m_ZExtOrSelf(Opnd &&Op) {
+  return Or<UnaryOpc_match<Opnd>, Opnd>(m_ZExt(std::forward<Opnd>(Op)),
+                                        std::forward<Opnd>(Op));
+}
+
+/// Match a sext or identity
+/// Allows to peek through optional extensions
+template <typename Opnd>
+inline Or<UnaryOpc_match<Opnd>, Opnd> m_SExtOrSelf(Opnd &&Op) {
+  return Or<UnaryOpc_match<Opnd>, Opnd>(m_SExt(std::forward<Opnd>(Op)),
+                                        std::forward<Opnd>(Op));
+}
+
+/// Match a aext or identity
+/// Allows to peek through optional extensions
+template <typename Opnd>
+inline Or<UnaryOpc_match<Opnd>, Opnd> m_AExtOrSelf(Opnd &&Op) {
+  return Or<UnaryOpc_match<Opnd>, Opnd>(m_AnyExt(std::forward<Opnd>(Op)),
+                                        std::forward<Opnd>(Op));
+}
+
+/// Match a trunc or identity
+/// Allows to peek through optional truncations
+template <typename Opnd>
+inline Or<UnaryOpc_match<Opnd>, Opnd> m_TruncOrSelf(Opnd &&Op) {
+  return Or<UnaryOpc_match<Opnd>, Opnd>(m_Trunc(std::forward<Opnd>(Op)),
+                                        std::forward<Opnd>(Op));
+}
+
 } // namespace SDPatternMatch
 } // namespace llvm
 #endif
diff --git a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
index 1967a62bbf9d11..a7112cfac63de5 100644
--- a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
+++ b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
@@ -251,6 +251,38 @@ TEST_F(SelectionDAGPatternMatchTest, patternCombinators) {
   EXPECT_TRUE(sd_match(Add, m_AllOf(m_Opc(ISD::ADD), m_OneUse())));
 }
 
+TEST_F(SelectionDAGPatternMatchTest, optionalResizing) {
+  SDLoc DL;
+  auto Int32VT = EVT::getIntegerVT(Context, 32);
+  auto Int64VT = EVT::getIntegerVT(Context, 64);
+
+  SDValue Op32 = DAG->getCopyFromReg(DAG->getEntryNode(), DL, 1, Int32VT);
+  SDValue Op64 = DAG->getCopyFromReg(DAG->getEntryNode(), DL, 1, Int64VT);
+  SDValue ZExt = DAG->getNode(ISD::ZERO_EXTEND, DL, Int64VT, Op32);
+  SDValue SExt = DAG->getNode(ISD::SIGN_EXTEND, DL, Int64VT, Op32);
+  SDValue AExt = DAG->getNode(ISD::ANY_EXTEND, DL, Int64VT, Op32);
+  SDValue Trunc = DAG->getNode(ISD::TRUNCATE, DL, Int32VT, Op64);
+
+  using namespace SDPatternMatch;
+  SDValue A;
+  EXPECT_TRUE(sd_match(Op32, m_ZExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op32);
+  EXPECT_TRUE(sd_match(ZExt, m_ZExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op32);
+  EXPECT_TRUE(sd_match(Op64, m_SExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op64);
+  EXPECT_TRUE(sd_match(SExt, m_SExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op32);
+  EXPECT_TRUE(sd_match(Op32, m_AExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op32);
+  EXPECT_TRUE(sd_match(AExt, m_AExtOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op32);
+  EXPECT_TRUE(sd_match(Op64, m_TruncOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op64);
+  EXPECT_TRUE(sd_match(Trunc, m_TruncOrSelf(m_Value(A))));
+  EXPECT_TRUE(A == Op64);
+}
+
 TEST_F(SelectionDAGPatternMatchTest, matchNode) {
   SDLoc DL;
   auto Int32VT = EVT::getIntegerVT(Context, 32);