[llvm] IR: introduce struct with CmpInst::Predicate and samesign (PR #116867)

[Nikita Popov via llvm-commits]

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@@ -0,0 +1,62 @@
+//===- CmpPredicate.h - CmpInst Predicate with samesign information -------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// A CmpInst::Predicate with any samesign information (applicable to ICmpInst).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_CMPPREDICATE_H
+#define LLVM_IR_CMPPREDICATE_H
+
+#include "llvm/IR/InstrTypes.h"
+
+namespace llvm {
+/// An abstraction over a floating-point predicate, and a pack of an integer
+/// predicate with samesign information. Some functions in ICmpInst construct
+/// and return this type in place of a Predicate.
+class CmpPredicate {
+  CmpInst::Predicate Pred;
+  bool HasSameSign;
+
+public:
+  // Constructed implictly with a either Predicate and samesign information, or
+  // just a Predicate, dropping samesign information.
+  CmpPredicate(CmpInst::Predicate Pred, bool HasSameSign = false)
+      : Pred(Pred), HasSameSign(HasSameSign) {
+    assert(!HasSameSign || CmpInst::isIntPredicate(Pred));
+  }
+
+  // Implictly converts to the underlying Predicate, dropping samesign
+  // information.
+  operator CmpInst::Predicate() const { return Pred; }
+
+  // Query samesign information, for optimizations.
----------------
nikic wrote:

```suggestion
  /// Query samesign information, for optimizations.
```
etc

https://github.com/llvm/llvm-project/pull/116867