llvm-6502/docs
Philip Reames d1940dcca7 Clarify wording in the LangRef around !invariant.load
Clarify the wording around !invariant.load to properly reflect the semantics of such loads with respect to control dependence and location lifetime.  To the best of my knowledge, the revised wording respects the actual implementation and understanding of issues involved highlighted in the recent 'Optimization hints for "constant" loads' thread on LLVMDev.  

In particular, I'm aiming for the following results:
- To clarify that an invariant.load can fault and must respect control dependence.  In particular, it is not sound to unconditionally pull an invariant load out of a loop if that loop would potentially never execute.  
- To clarify that the invariant nature of a given pointer does not preclude the modification of that location through a pointer which is unrelated to the load operand.  In particular, initializing a location and then passing a pointer through an opaque intrinsic which produces a new unrelated pointer, should behave as expected provided that the intrinsic is memory dependent on the initializing store.  
- To clarify that storing a value to an invariant location is defined.  It can not, for example, be considered unreachable.  The value stored can be assumed to be equal to the value of any previous (or following!) invariant load, but the store itself is defined.  

I recommend that anyone interested in using !invariant.load, or optimizing for them, read over the discussion in the review thread.  A number of motivating examples are discussed.

Differential Revision: http://reviews.llvm.org/D6346



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222700 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-24 22:32:43 +00:00
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CommandGuide [llvm-symbolizer] Introduce the -dsym-hint option. 2014-10-17 00:50:19 +00:00
HistoricalNotes
TableGen Fix typo in TableGen documentation 2014-10-03 20:46:05 +00:00
tutorial [Docs][JIT] Update the clang++ invocation lines in the kaleidoscope docs. 2014-11-06 00:31:04 +00:00
AliasAnalysis.rst Update some AliasAnalysis pass docs for getAdjustedAnalysisPointer. 2014-05-22 19:38:25 +00:00
ARM-BE-bitcastfail.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-bitcastsuccess.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-ld1.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-ldr.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
Atomics.rst [sphinx cleanup] Fix unexpected indentation warning introduced by r218937 2014-10-03 12:28:48 +00:00
BigEndianNEON.rst Fix typos 2014-05-15 01:52:21 +00:00
BitCodeFormat.rst Fix sphinx warning. 2014-09-18 21:54:02 +00:00
BlockFrequencyTerminology.rst Fix typos 2014-05-15 01:52:21 +00:00
BranchWeightMetadata.rst
Bugpoint.rst
CMake.rst Use ninja pools to limit the number of concurrent compile/link jobs. 2014-11-19 10:30:02 +00:00
CMakeLists.txt
CodeGenerator.rst [sphinx cleanup] 2014-09-10 20:43:03 +00:00
CodingStandards.rst Introduce Go coding standards for LLVM. 2014-10-14 00:40:53 +00:00
CommandLine.rst Update the example of using a command-line option custom parser to 2014-10-13 21:11:22 +00:00
CompilerWriterInfo.rst Update documentation with link to Sea Islands documentation 2014-10-06 18:31:09 +00:00
conf.py Update LLVM version: 3.5 => 3.6 2014-07-28 22:10:52 +00:00
CoverageMappingFormat.rst Docs: add documentation for the coverage mapping format. 2014-08-19 17:05:58 +00:00
DebuggingJITedCode.rst
DeveloperPolicy.rst Document what backwards compatibility we provide for bitcode. 2014-07-23 22:43:22 +00:00
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ExtendingLLVM.rst Correct path to regression tests in ExtendingLLVM 2014-11-24 19:40:07 +00:00
Extensions.rst ARM: add VLA extension for WoA Itanium ABI 2014-06-09 20:18:42 +00:00
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GettingStartedVS.rst Document how to select build configuration with Visual C++ IDE or command line. 2014-06-05 16:42:26 +00:00
GoldPlugin.rst Docs: give binutils/gold instructions for CMake too. 2014-11-04 02:16:03 +00:00
HowToAddABuilder.rst
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HowToReleaseLLVM.rst docs: Update relaease documents to include the patch number in the RELEASE tags 2014-07-21 14:28:31 +00:00
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HowToSubmitABug.rst Delete -std-compile-opts. 2014-10-16 20:00:02 +00:00
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index.rst R600/SI: Start implementing an assembler 2014-11-14 14:08:00 +00:00
LangRef.rst Clarify wording in the LangRef around !invariant.load 2014-11-24 22:32:43 +00:00
Lexicon.rst [docs] Document what "NFC" means in a commit message. 2014-09-06 00:19:16 +00:00
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Phabricator.rst Phabricator doc: Explicit the fact that the patch needs to be there before the commit 2014-07-04 09:00:35 +00:00
ProgrammersManual.rst Update my previous commit to fit 80 cols... 2014-09-25 10:58:16 +00:00
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TestingGuide.rst [docs] Document usage of Inputs/ for extra test files. 2014-11-05 22:17:18 +00:00
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Vectorizers.rst Vectorization documentation for loop hint pragmas and Rpass diagnostics. 2014-06-27 18:30:08 +00:00
WritingAnLLVMBackend.rst configure.ac lives in autoconf/, not autotools/ 2014-11-10 22:36:04 +00:00
WritingAnLLVMPass.rst docs: Modernize some examples in WritingAnLLVMPass 2014-11-18 05:22:39 +00:00
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