[llvm] [NVPTX] Add IR pass for FMA transformation in the llc pipeline (PR #154735)

[Rajat Bajpai via llvm-commits]

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+//===------ NVPTXFoldFMA.cpp - Fold FMA --------------===//
+//
+// 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 implements FMA folding for float/double type for NVPTX. It folds
+// following patterns:
+// 1. fadd(fmul(a, b), c) => fma(a, b, c)
+// 2. fadd(c, fmul(a, b)) => fma(a, b, c)
+// 3. fadd(fmul(a, b), fmul(c, d)) => fma(a, b, fmul(c, d))
+// 4. fsub(fmul(a, b), c) => fma(a, b, fneg(c))
+// 5. fsub(a, fmul(b, c)) => fma(fneg(b), c, a)
+// 6. fsub(fmul(a, b), fmul(c, d)) => fma(a, b, fneg(fmul(c, d)))
+//===----------------------------------------------------------------------===//
+
+#include "NVPTXUtilities.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+
+#define DEBUG_TYPE "nvptx-fold-fma"
+
+using namespace llvm;
+
+static bool tryFoldBinaryFMul(BinaryOperator *BI, Value *MulOperand,
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rajatbajpai wrote:

Makes sense, done. Thanks!

https://github.com/llvm/llvm-project/pull/154735