While there, I noticed that the transform "undef >>a X -> undef" was wrong.
For example if X is 2 then the top two bits must be equal, so the result can
not be anything. I fixed this in the constant folder as well. Also, I made
the transform for "X << undef" stronger: it now folds to undef always, even
though X might be zero. This is in accordance with the LangRef, but I must
admit that it is fairly aggressive. Also, I added "i32 X << 32 -> undef"
following the LangRef and the constant folder, likewise fairly aggressive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123417 91177308-0d34-0410-b5e6-96231b3b80d8
"this" pointer for any subclass of User, you could static_cast it to
User* and then reinterpret_cast that to Use* to get the end of the
operand list. This isn't a safe assumption in general, because the
static_cast might adjust the "this" pointer. Fixed by having these
OperandTraits classes take an extra template parameter, which is the
subclass of User. This is groundwork for PR889.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123235 91177308-0d34-0410-b5e6-96231b3b80d8
Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.
If an optimization pass can show that an address is not used, it can set this.
Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.
Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.
Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123063 91177308-0d34-0410-b5e6-96231b3b80d8
headers provide symbols outside namespace std and the LLVM coding standards
state that we should prefix all of them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122192 91177308-0d34-0410-b5e6-96231b3b80d8
uses of the function's blocks with undef. This code isn't needed,
because BasicBlock's destructor handles such uses. Also, undef isn't
correct, since blockaddresses may still be used for comparisons
with null.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121170 91177308-0d34-0410-b5e6-96231b3b80d8
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121120 91177308-0d34-0410-b5e6-96231b3b80d8
Also add asserts that the indices are valid in InsertValueInst::init(). ExtractValueInst already asserts when constructed with invalid indices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120956 91177308-0d34-0410-b5e6-96231b3b80d8
phi node itself if it occurs in an unreachable basic block. Protect
against this. Hopefully this will fix some more buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119493 91177308-0d34-0410-b5e6-96231b3b80d8
cookie argument to the SourceMgr diagnostic stuff. This cleanly separates
LLVMContext's inlineasm handler from the sourcemgr error handling
definition, increasing type safety and cleaning things up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119486 91177308-0d34-0410-b5e6-96231b3b80d8
class, uses DominatorTree which is an analysis. This change moves all of
the tricky hasConstantValue logic to SimplifyInstruction, and replaces it
with a very simple literal implementation. I already taught users of
hasConstantValue that need tricky stuff to use SimplifyInstruction instead.
I didn't update InlineFunction because the IR looks like it might be in a
funky state at the point it calls hasConstantValue, which makes calling
SimplifyInstruction dangerous since it can in theory do a lot of tricky
reasoning. This may be a pessimization, for example in the case where
all phi node operands are either undef or a fixed constant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119459 91177308-0d34-0410-b5e6-96231b3b80d8
testing for dereferenceable pointers into a helper function,
isDereferenceablePointer. Teach it how to reason about GEPs
with simple non-zero indices.
Also eliminate ArgumentPromtion's IsAlwaysValidPointer,
which didn't check for weak externals or out of range gep
indices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118840 91177308-0d34-0410-b5e6-96231b3b80d8
