llvm-project/llvm
Whitney Tsang 1ccba7c1a1 LLVM: Optimization Pass: Remove conflicting attribute, if any, before
adding new read attribute to an argument
Summary: Update optimization pass to prevent adding read-attribute to an
argument without removing its conflicting attribute.

A read attribute, based on the result of the attribute deduction
process, might be added to an argument. The attribute might be in
conflict with other read/write attribute currently associated with the
argument. To ensure the compatibility of attributes, conflicting
attribute, if any, must be removed before a new one is added.

The following snippet shows the current behavior of the compiler, where
the compilation process is aborted due to incompatible attributes.

$ cat x.ll
; ModuleID = 'x.bc'

%_type_of_d-ccc = type <{ i8*, i8, i8, i8, i8 }>

@d-ccc = internal global %_type_of_d-ccc <{ i8* null, i8 1, i8 13, i8 0,
i8 -127 }>, align 8

define void @foo(i32* writeonly %.aaa) {
foo_entry:
  %_param_.aaa = alloca i32*, align 8
  store i32* %.aaa, i32** %_param_.aaa, align 8
  store i8 0, i8* getelementptr inbounds (%_type_of_d-ccc,
%_type_of_d-ccc* @d-ccc, i32 0, i32 3)
  ret void
}

$ opt -O3 x.ll
Attributes 'readnone and writeonly' are incompatible!
void (i32*)* @foo
in function foo
LLVM ERROR: Broken function found, compilation aborted!
The purpose of this changeset is to fix the above error. This fix is
based on a suggestion from Johannes @jdoerfert (many thanks!!!)
Authored By: anhtuyen
Reviewer: nicholas, rnk, chandlerc, jdoerfert
Reviewed By: rnk
Subscribers: hiraditya, jdoerfert, llvm-commits, anhtuyen, LLVM
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D58694

llvm-svn: 371622
2019-09-11 14:26:22 +00:00
..
benchmarks
bindings
cmake [CMake] Don't pass all LLVM_COMPILE_FLAGS to the C compiler 2019-09-10 14:19:52 +00:00
docs [LangRef] add link for fma intrinsic 2019-09-11 13:25:32 +00:00
examples [ORCv2] - New Speculate Query Implementation 2019-08-27 18:23:36 +00:00
include [Alignment][NFC] use llvm::Align for AsmPrinter::EmitAlignment 2019-09-11 13:37:35 +00:00
lib LLVM: Optimization Pass: Remove conflicting attribute, if any, before 2019-09-11 14:26:22 +00:00
projects
resources
runtimes Revert "Adding support for overriding LLVM_ENABLE_RUNTIMES for runtimes builds." 2019-09-11 00:43:35 +00:00
test LLVM: Optimization Pass: Remove conflicting attribute, if any, before 2019-09-11 14:26:22 +00:00
tools Fix -Wdocumentation warning - void function doesn't need a @returns. NFCI. 2019-09-11 11:12:00 +00:00
unittests Reland [DWARF] Add a unit test for DWARFUnit::getLength(). 2019-09-10 11:54:32 +00:00
utils gn build: add include_dir that's necessary after r371564 2019-09-11 12:21:09 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitattributes Fix the "git modified" issue on the preserve-comments-crlf.s. 2019-09-10 12:17:49 +00:00
.gitignore
CMakeLists.txt Revert "[utils] Implement the llvm-locstats tool" 2019-09-10 14:48:52 +00:00
CODE_OWNERS.TXT
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
README.txt
RELEASE_TESTERS.TXT
configure
llvm.spec.in

README.txt

The LLVM Compiler Infrastructure
================================

This directory and its subdirectories contain source code for LLVM,
a toolkit for the construction of highly optimized compilers,
optimizers, and runtime environments.

LLVM is open source software. You may freely distribute it under the terms of
the license agreement found in LICENSE.txt.

Please see the documentation provided in docs/ for further
assistance with LLVM, and in particular docs/GettingStarted.rst for getting
started with LLVM and docs/README.txt for an overview of LLVM's
documentation setup.

If you are writing a package for LLVM, see docs/Packaging.rst for our
suggestions.