[ADT] Add a 'find_as' operation to DenseSet.

This operation is analogous to its counterpart in DenseMap: It allows lookup
via cheap-to-construct keys (provided that getHashValue and isEqual are
implemented for the cheap key-type in the DenseMapInfo specialization).

Thanks to Chandler for the review.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220168 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Re-enable VSX test line for fma.ll with -mcpu=pwr7

The VSX testing variant in test/CodeGen/PowerPC/fma.ll had to be
disabled because of unexpected behavior on many of the builders.  I
tracked this down to a situation that occurs when the VSX attribute is
enabled for a target that disables the MI early scheduling pass.  This
patch adds -mcpu=pwr7 to make this predictable.  The other issue will
be addressed separately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220171 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Temporarily disable VSX for PowerPC fast-isel tests

Patch by Bill Seurer; some comment formatting changes by me.

There are a few PowerPC test cases for FastISel support that currently
fail with VSX support enabled.  The temporary workaround under
discussion in http://reviews.llvm.org/D5362 helps, but the tests still
fail because they specify -fast-isel-abort, and the VSX workaround
punts back to SelectionDAG.  We have plans to fix FastISel permanently
for VSX, but until that's in place these tests are preventing us from
enabling VSX by default.  Therefore we are adding -mattr=-vsx to these
tests until the full support is ready.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220172 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Clean up -mattr=+vsx tests to always specify -mcpu

We recently discovered an issue that reinforces what a good idea it is
to always specify -mcpu in our code generation tests, particularly for
-mattr=+vsx.  This patch ensures that all tests that specify
-mattr=+vsx also specify -mcpu=pwr7 or -mcpu=pwr8, as appropriate.

Some of the uses of -mattr=+vsx added recently don't make much sense
(when specified for -mtriple=powerpc-apple-darwin8 or -march=ppc32,
for example).  For cases like this I've just removed the extra VSX
test commands; there's enough coverage without them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220173 91177308-0d34-0410-b5e6-96231b3b80d8
Always use -Wl,-gc-sections on our build.

Both bfd ld and gold correctly handle --export-dynamic, so gc-sections is safe even for binaries
that support plugins.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220174 91177308-0d34-0410-b5e6-96231b3b80d8
Add a datalayout string to this test so that it exercises the full gamut
of InstCombine rather than just the bits enabled when datalayout is
optional.

The primary fixes here are because now things are little endian.

In good news, silliness like this seems like it will be going away as
we've got pretty stong consensus on dropping optional datalayout
entirely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220176 91177308-0d34-0410-b5e6-96231b3b80d8
Teach the load analysis driving core instcombine logic and other bits of
logic to look through pointer casts, making them trivially stronger in
the face of loads and stores with intervening pointer casts.

I've included a few test cases that demonstrate the kind of folding
instcombine can do without pointer casts and then variations which
obfuscate the logic through bitcasts. Without this patch, the variations
all fail to optimize fully.

This is more important now than it has been in the past as I've started
moving the load canonicialization to more closely follow the value type
requirements rather than the pointer type requirements and thus this
needs to be prepared for more pointer casts. When I made the same change
to stores several test cases regressed without logic along these lines
so I wanted to systematically improve matters first.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220178 91177308-0d34-0410-b5e6-96231b3b80d8
[PBQP] Use DenseSet rather than std::set for PBQP's PoolCostAllocator
implementation.

This is good for a ~6% reduction in total compile time on the nightly test suite
when running with -regalloc=pbqp.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220183 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a somewhat subtle pair of issues with JumpThreading I introduced in
r220178. First, the creation routine doesn't insert prior to the
terminator of the basic block provided, but really at the end of the
basic block. Instead, get the terminator and insert before that. The
next issue was that we need to ensure multiple PHI node entries for
a single predecessor re-use the same cast instruction rather than
creating new ones.

All of the logic here was without tests previously. I've reduced and
added a test case from the test suite that crashed without both of these
fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220186 91177308-0d34-0410-b5e6-96231b3b80d8
IR: Replace DataLayout::RoundUpAlignment with RoundUpToAlignment

No functional change intended, just cleaning up some code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220187 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a miscompile introduced in r220178.

The original code had an implicit assumption that if the test for
allocas or globals was reached, the two pointers were not equal. With my
changes to make the pointer analysis more powerful here, I also had to
guard against circumstances where the results weren't useful. That in
turn violated the assumption and gave rise to a circumstance in which we
could have a store with both the queried pointer and stored pointer
rooted at *the same* alloca. Clearly, we cannot ignore such a store.
There are other things we might do in this code to better handle the
case of both pointers ending up at the same alloca or global, but it
seems best to at least make the test explicit in what it intends to
check.

I've added tests for both the alloca and global case here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220190 91177308-0d34-0410-b5e6-96231b3b80d8
Clean up the comments and doxygen for DataLayout.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220191 91177308-0d34-0410-b5e6-96231b3b80d8
Remove some completely superfluous trailing comments and clang-format
this header to remove numerous formatting inconsistencies that impede
making simple changes here without large diffs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220192 91177308-0d34-0410-b5e6-96231b3b80d8
Switch the default DataLayout to be little endian, and make the variable
be BigEndian so the default can continue to be zero-initialized.

This is one of the prerequisites to making DataLayout a constant and
always available part of every module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220193 91177308-0d34-0410-b5e6-96231b3b80d8
[Thumb] Fix crash in Thumb1RegisterInfo::rewriteFrameIndex

This function can, for some offsets from the SP, split one instruction
into two. Since it re-uses the original instruction as the first
instruction of the result, we need ensure its result register is not
marked as dead before we use it in the second instruction.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220194 91177308-0d34-0410-b5e6-96231b3b80d8
[ARM] Do not select SMULW[BT] or SMLAW[BT]

The current instruction selection patterns for SMULW[BT] and SMLAW[BT]
are incorrect. These instructions multiply a 32-bit and a 16-bit value
(both signed) and return the top 32 bits of the 48-bit result. This
preserves the 16 bits of overflow, whereas the patterns they currently
match truncate the result to 16 bits then sign extend.

To select these instructions, we would need to match an ISD::SMUL_LOHI,
a sign extend, two shifts and an or. There is no way to match SMUL_LOHI
in an instruction pattern as it defines multiple values, so this would
have to be done in C++. I have raised
http://llvm.org/bugs/show_bug.cgi?id=21297 to cover allowing correct
selection of these instructions.

This fixes http://llvm.org/bugs/show_bug.cgi?id=19396



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220196 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r220174, "Always use -Wl,-gc-sections on our build."

It dropped required functions for plugins with gnu ld 2.20 and 2.21.

  Failing Tests (1):
      LLVM :: Feature/load_module.ll

  Hello: bin/opt: symbol lookup error: lib/LLVMHello.so: undefined symbol: _ZN4llvm11raw_ostream13write_escapedENS_9StringRefEb

  Failing Tests (1):
      Clang :: Frontend/plugins.c

  error: unable to load plugin 'lib/PrintFunctionNames.so': 'lib/PrintFunctionNames.so: undefined symbol: _ZN5clang15PluginASTAction6anchorEv'

I think we should inspect linker's version or behavior to introduce --gc-sections for --export-dynamic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220198 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary else.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220200 91177308-0d34-0410-b5e6-96231b3b80d8
[Thumb2] RFE, SRS and "SUBS pc, lr" are undefined on v7M

These instructions are related to the v7[AR] exception model, and are
not defined on v7M.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220204 91177308-0d34-0410-b5e6-96231b3b80d8
Fix Intrinsic::getType not working with vararg

VarArg Intrinsic functions are encoded with "void" type as the last
argument. Now Intrinsic::getType can correctly return all the intrinsic
function type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220205 91177308-0d34-0410-b5e6-96231b3b80d8