[llvm] [LLVM][Instrumentation] Add numerical sanitizer (PR #85916)

[Vitaly Buka via llvm-commits]

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@@ -0,0 +1,36 @@
+//===- NumericalStabilitySanitizer.h - NSan Pass ---------------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines the numerical stability sanitizer (nsan) pass.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_INSTRUMENTATION_NUMERICALSTABIITYSANITIZER_H
+#define LLVM_TRANSFORMS_INSTRUMENTATION_NUMERICALSTABIITYSANITIZER_H
+
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+
+namespace llvm {
+
+/// A function pass for nsan instrumentation.
+///
+/// Instruments functions to duplicate floating point computations in a
+/// higher-precision type.
+/// This pass inserts calls to runtime library functions. If the
+/// functions aren't declared yet, the pass inserts the declarations.
+struct NumericalStabilitySanitizerPass
+    : public PassInfoMixin<NumericalStabilitySanitizerPass> {
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
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vitalybuka wrote:

Would be nice to pre-commit  tests without instrumentation. So it would be easy to see diff of how intrumentation transform the code.
E.g. this patch with empty ::run() body

https://github.com/llvm/llvm-project/pull/85916