llvm-project/llvm
James Molloy 493e57de01 [ValueTracking] Extend r251146 to catch a fairly common case
Even though we may not know the value of the shifter operand, it's possible we know the shifter operand is non-zero. This can allow us to infer more known bits - for example:

  %1 = load %p !range {1, 5}
  %2 = shl %q, %1

We don't know %1, but we do know that it is nonzero so %2[0] is known zero, and importantly %2 is known non-zero.

Calling isKnownNonZero is nontrivially expensive so use an Optional to run it lazily and cache its result.

llvm-svn: 251294
2015-10-26 14:10:46 +00:00
..
autoconf Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
bindings [OCaml] Expose Llvm.{set_,}unnamed_addr. 2015-10-21 17:43:02 +00:00
cmake [CMake] Fixing dependency issue with parallel make when building with LLVM_OPTIMIZED_TABLEGEN. 2015-10-23 19:48:17 +00:00
docs docs: document `x` mangling in LangRef 2015-10-25 20:39:35 +00:00
examples [JIT/Examples] Fix Fibonacci so that it runs again. 2015-10-17 06:36:46 +00:00
include [SCEV] Fix issues found during the review of r251283. NFC. 2015-10-26 13:50:06 +00:00
lib [ValueTracking] Extend r251146 to catch a fairly common case 2015-10-26 14:10:46 +00:00
projects
resources
test [ValueTracking] Extend r251146 to catch a fairly common case 2015-10-26 14:10:46 +00:00
tools Simplify boolean conditional return statements in tools/llvm-symbolizer. 2015-10-24 23:23:25 +00:00
unittests [X86] Add support for elfiamcu triple 2015-10-25 08:07:37 +00:00
utils [TblGen] ArrayRefize CodeGenSchedule. No functionality change intended. 2015-10-24 12:46:49 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] All the checks for if LLVM_VERSION_* variables are set need to be if(DEFINED ...) 2015-10-20 18:16:37 +00:00
CODE_OWNERS.TXT CODE_OWNERS.TXT is supposed to be sorted by surname 2015-09-07 00:41:40 +00:00
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in
Makefile.rules
README.txt
configure Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
llvm.spec.in

README.txt

Low Level Virtual Machine (LLVM)
================================

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're writing a package for LLVM, see docs/Packaging.rst for our
suggestions.