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

[Marc Auberer via llvm-commits]

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

Fixes #85395

>From e9d8ada9331439a8b8e8bc9bb91d66ef76ed8381 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  | 29 ++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/llvm/include/llvm/CodeGen/SDPatternMatch.h b/llvm/include/llvm/CodeGen/SDPatternMatch.h
index 96ab6b160a1c77..ba34f1cc81811c 100644
--- a/llvm/include/llvm/CodeGen/SDPatternMatch.h
+++ b/llvm/include/llvm/CodeGen/SDPatternMatch.h
@@ -725,6 +725,39 @@ inline auto m_False() {
       },
       m_Value()};
 }
+
+/// Match a zext or identity
+/// Allows to peek through optional extensions
+template <typename LHS, typename RHS>
+inline BinaryOpc_match<LHS, RHS, true> m_ZExtOrSelf(const LHS &L,
+                                                    const RHS &R) {
+  return m_Or(m_ZExt(L), R);
+}
+
+/// Match a sext or identity
+/// Allows to peek through optional extensions
+template <typename LHS, typename RHS>
+inline BinaryOpc_match<LHS, RHS, true> m_SExtOrSelf(const LHS &L,
+                                                    const RHS &R) {
+  return m_Or(m_SExt(L), R);
+}
+
+/// Match a aext or identity
+/// Allows to peek through optional extensions
+template <typename LHS, typename RHS>
+inline BinaryOpc_match<LHS, RHS, true> m_AExtOrSelf(const LHS &L,
+                                                    const RHS &R) {
+  return m_Or(m_AnyExt(L), R);
+}
+
+/// Match a trunc or identity
+/// Allows to peek through optional truncations
+template <typename LHS, typename RHS>
+inline BinaryOpc_match<LHS, RHS, true> m_TruncOrSelf(const LHS &L,
+                                                     const RHS &R) {
+  return m_Or(m_Trunc(L), R);
+}
+
 } // namespace SDPatternMatch
 } // namespace llvm
 #endif
diff --git a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
index 180d4306a470f7..d803ac8bf3f450 100644
--- a/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
+++ b/llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp
@@ -241,6 +241,35 @@ 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);
+
+  SDValue Op0 = DAG->getCopyFromReg(DAG->getEntryNode(), DL, 1, Int32VT);
+
+  // zero extend
+  SDValue ZExt = DAG->getNode(ISD::ZERO_EXTEND, DL, Int32VT, Op0);
+  SDValue OptionalZExt = DAG->getNode(ISD::OR, DL, Int32VT, Op0, ZExt);
+
+  // sign extend
+  SDValue SExt = DAG->getNode(ISD::SIGN_EXTEND, DL, Int32VT, Op0);
+  SDValue OptionalSExt = DAG->getNode(ISD::OR, DL, Int32VT, Op0, SExt);
+
+  // any extend
+  SDValue AExt = DAG->getNode(ISD::ANY_EXTEND, DL, Int32VT, Op0);
+  SDValue OptionalAExt = DAG->getNode(ISD::OR, DL, Int32VT, Op0, AExt);
+
+  // truncate
+  SDValue Trunc = DAG->getNode(ISD::TRUNCATE, DL, Int32VT, Op0);
+  SDValue OptionalTrunc = DAG->getNode(ISD::OR, DL, Int32VT, Op0, Trunc);
+
+  using namespace SDPatternMatch;
+  EXPECT_TRUE(sd_match(OptionalZExt, m_ZExtOrSelf(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(OptionalSExt, m_SExtOrSelf(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(OptionalAExt, m_AExtOrSelf(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(OptionalTrunc, m_TruncOrSelf(m_Value(), m_Value())));
+}
+
 TEST_F(SelectionDAGPatternMatchTest, matchNode) {
   SDLoc DL;
   auto Int32VT = EVT::getIntegerVT(Context, 32);