[llvm] [SCEV] Add initial pattern matching for SCEV constants. (NFC) (PR #119389)

[Florian Hahn via llvm-commits]

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@@ -0,0 +1,45 @@
+//===- ScalarEvolutionPatternMatch.h - Match on SCEVs -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides a simple and efficient mechanism for performing general
+// tree-based pattern matches on SCEVs, based on LLVM's IR pattern matchers.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONPATTERNMATCH_H
+#define LLVM_ANALYSIS_SCALAREVOLUTIONPATTERNMATCH_H
+
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/IR/PatternMatch.h"
+
+namespace llvm {
+namespace SCEVPatternMatch {
+
+template <typename Val, typename Pattern>
+bool match(const SCEV *S, const Pattern &P) {
+  return P.match(S);
+}
+
+struct specific_intval64 : public PatternMatch::specific_intval64<false> {
+  specific_intval64(uint64_t V) : PatternMatch::specific_intval64<false>(V) {}
+
+  bool match(const SCEV *S) {
+    auto *Cast = dyn_cast<SCEVConstant>(S);
+    return Cast &&
+           PatternMatch::specific_intval64<false>::match(Cast->getValue());
+  }
+};
+
+inline specific_intval64 m_scev_Zero() { return specific_intval64(0); }
+inline specific_intval64 m_scev_One() { return specific_intval64(1); }
+inline specific_intval64 m_scev_MinusOne() { return specific_intval64(-1); }
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fhahn wrote:

Ah I see, I misunderstood originally. Should be updated, thanks

https://github.com/llvm/llvm-project/pull/119389