1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-25 20:23:11 +01:00
llvm-mirror/lib/IR/Assumptions.cpp
Johannes Doerfert 6230d2a2a4 [Clang][Attr] Introduce the assume function attribute
The `assume` attribute is a way to provide additional, arbitrary
information to the optimizer. For now, assumptions are restricted to
strings which will be accumulated for a function and emitted as comma
separated string function attribute. The key of the LLVM-IR function
attribute is `llvm.assume`. Similar to `llvm.assume` and
`__builtin_assume`, the `assume` attribute provides a user defined
assumption to the compiler.

A follow up patch will introduce an LLVM-core API to query the
assumptions attached to a function. We also expect to add more options,
e.g., expression arguments, to the `assume` attribute later on.

The `omp [begin] asssumes` pragma will leverage this attribute and
expose the functionality in the absence of OpenMP.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D91979
2020-12-15 16:51:34 -06:00

37 lines
1.2 KiB
C++

//===- Assumptions.cpp ------ Collection of helpers for assumptions -------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Assumptions.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
using namespace llvm;
bool llvm::hasAssumption(Function &F,
const KnownAssumptionString &AssumptionStr) {
const Attribute &A = F.getFnAttribute(AssumptionAttrKey);
if (!A.isValid())
return false;
assert(A.isStringAttribute() && "Expected a string attribute!");
SmallVector<StringRef, 8> Strings;
A.getValueAsString().split(Strings, ",");
return llvm::any_of(Strings, [=](StringRef Assumption) {
return Assumption == AssumptionStr;
});
}
StringSet<> llvm::KnownAssumptionStrings({
"omp_no_openmp", // OpenMP 5.1
"omp_no_openmp_routines", // OpenMP 5.1
"omp_no_parallelism", // OpenMP 5.1
});