llvm-project/llvm
Ulrich Weigand eaf0051ba3 [SystemZ] Remove unnecessary serialization before volatile loads
This reverts the use of TargetLowering::prepareVolatileOrAtomicLoad
introduced by r196905.  Nothing in the semantics of the "volatile"
keyword or the definition of the z/Architecture actually requires
that volatile loads are preceded by a serialization operation, and
no other compiler on the platform actually implements this.

Since we've now seen a use case where this additional serialization
causes noticable performance degradation, this patch removes it.

The patch still leaves in the serialization before atomic loads,
which is now implemented directly in lowerATOMIC_LOAD.  (This also
seems overkill, but that can be addressed separately.)

llvm-svn: 306117
2017-06-23 15:56:14 +00:00
..
bindings [Go] Subtypes function 2017-06-08 07:32:29 +00:00
cmake TableGen.cmake: Use DEPFILE for Ninja Generator with CMake>=3.7. 2017-06-21 22:04:07 +00:00
docs [docs] As of binutils 2.21.51.0.2, ld.bfd supports plugins too, represent this in docs 2017-06-23 13:54:10 +00:00
examples [ORC] Switch the object layer API from addObjectSet to addObject (singular), and 2017-06-22 21:06:54 +00:00
include Fix build breakage caused by r306096 2017-06-23 13:13:06 +00:00
lib [SystemZ] Remove unnecessary serialization before volatile loads 2017-06-23 15:56:14 +00:00
projects Add temporary workaround to allow in-tree libc++ builds on Windows 2017-05-11 01:44:30 +00:00
resources
runtimes [CMake][runtimes] Add install target for runtimes builtins 2017-06-02 19:38:11 +00:00
test [SystemZ] Remove unnecessary serialization before volatile loads 2017-06-23 15:56:14 +00:00
tools [ORC] Switch the object layer API from addObjectSet to addObject (singular), and 2017-06-22 21:06:54 +00:00
unittests Fix double->float truncation warning on MSVC 2017-06-23 13:53:55 +00:00
utils [TableGen] Take a parameter by reference instead of pointer so we don't have to add & on both callers. NFC 2017-06-20 16:34:37 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [Solaris] replace Solaris.h hack with a set of better hacks 2017-06-22 13:18:46 +00:00
CODE_OWNERS.TXT
CREDITS.TXT update of the url 2017-05-14 07:55:01 +00:00
LICENSE.TXT
LLVMBuild.txt
README.txt
RELEASE_TESTERS.TXT
configure
llvm.spec.in

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