Fix return sequence on armv4 thumb

POP on armv4t cannot be used to change thumb state (unilke later non-m-class
architectures), therefore we need a different return sequence that uses 'bx'
instead:

  POP {r3}
  ADD sp, #offset
  BX r3

This patch also fixes an issue where the return value in r3 would get clobbered
for functions that return 128 bits of data. In that case, we generate this
sequence instead:

  MOV ip, r3
  POP {r3}
  ADD sp, #offset
  MOV lr, r3
  MOV r3, ip
  BX lr

http://reviews.llvm.org/D4748



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214881 91177308-0d34-0410-b5e6-96231b3b80d8
Wrap long lines

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214884 91177308-0d34-0410-b5e6-96231b3b80d8
[AVX512] Pull everything alignr-related into the multiclass

The packed integer pattern becomes the DAG pattern for rri and the packed
float, another Pat<> inside the multiclass.

No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214885 91177308-0d34-0410-b5e6-96231b3b80d8
[AVX512] alignr: Use suffix rather than name argument to multiclass

Again no functional change.  This prepares for the suffix to be used with the
intrinsic matching.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214886 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Separate DAG node for valign and palignr

They have different semantics (valign is interlane while palingr is intralane)
and palingr is still needed even in the AVX512 context.  According to the
latest spec AVX512BW provides these.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214887 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Add lowering to VALIGN

This was currently part of lowering to PALIGNR with some special-casing to
make interlane shifting work.  Since AVX512F has interlane alignr (valignd/q)
and AVX512BW has vpalignr we need to support both of these *at the same time*,
e.g. for SKX.

This patch breaks out the common code and then add support to check both of
these lowering options from LowerVECTOR_SHUFFLE.

I also added some FIXMEs where I think the AVX512BW and AVX512VL additions
should probably go.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214888 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Increase X86_MAX_OPERANDS from 5 to 6

This controls the number of operands in the disassembler's x86OperandSets
table.  The entries describe how the operand is encoded and its type.

Not to surprisingly 5 operands is insufficient for AVX512.  Consider
VALIGNDrrik in the next patch.  These are its operand specifiers:

  { /* 328 */
    { ENCODING_DUP, TYPE_DUP1 },
    { ENCODING_REG, TYPE_XMM512 },
    { ENCODING_WRITEMASK, TYPE_VK8 },
    { ENCODING_VVVV, TYPE_XMM512 },
    { ENCODING_RM_CD64, TYPE_XMM512 },
    { ENCODING_IB, TYPE_IMM8 },
  },

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214889 91177308-0d34-0410-b5e6-96231b3b80d8
[AVX512] Add masking variant and intrinsics for valignd/q

This is similar to what I did with the two-source permutation recently.  (It's
almost too similar so that we should consider generating the masking variants
with some tablegen help.)

Both encoding and intrinsic tests are added as well.  For the latter, this is
what the IR that the intrinsic test on the clang side generates.

Part of <rdar://problem/17688758>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214890 91177308-0d34-0410-b5e6-96231b3b80d8
Optimize vector fabs of bitcasted constant integer values.

Allow vector fabs operations on bitcasted constant integer values to be optimized
in the same way that we already optimize scalar fabs.

So for code like this:
%bitcast = bitcast i64 18446744069414584320 to <2 x float> ; 0xFFFF_FFFF_0000_0000
%fabs = call <2 x float> @llvm.fabs.v2f32(<2 x float> %bitcast)
%ret = bitcast <2 x float> %fabs to i64

Instead of generating something like this:

movabsq (constant pool loadi of mask for sign bits)
vmovq   (move from integer register to vector/fp register)
vandps  (mask off sign bits)
vmovq   (move vector/fp register back to integer return register)

We should generate:

mov     (put constant value in return register)

I have also removed a redundant clause in the first 'if' statement:
N0.getOperand(0).getValueType().isInteger()

is the same thing as:
IntVT.isInteger()

Testcases for x86 and ARM added to existing files that deal with vector fabs.
One existing testcase for x86 removed because it is no longer ideal.

For more background, please see:
http://reviews.llvm.org/D4770

And:
http://llvm.org/bugs/show_bug.cgi?id=20354

Differential Revision: http://reviews.llvm.org/D4785


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214892 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r214881 because it broke lots of build-bots

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214893 91177308-0d34-0410-b5e6-96231b3b80d8
Remove dead zero store to calloc initialized memory

Optimize the following IR:

%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
; This store is dead and should be removed
store i32 0, i32* %2, align 4

Memory returned by calloc is guaranteed to be zero initialized. If the value being stored is the constant zero (and the store is not otherwise observable across threads), we can delete the store.  If the store is to an out of bounds address, it is undefined and thus also removable.

Reviewed By: nicholas

Differential Revision: http://reviews.llvm.org/D3942




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214897 91177308-0d34-0410-b5e6-96231b3b80d8
BitcodeReader: Fix non-determinism in use-list order

`BasicBlockFwdRefs` (and `BlockAddrFwdRefs` before it) was being emptied
in a non-deterministic order.  When predicting use-list order I've
worked around this another way, but even when parsing lazily (and we
can't recreate use-list order) use-lists should be deterministic.

Make them so by using a side-queue of functions with forward-referenced
blocks that gets visited in order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214899 91177308-0d34-0410-b5e6-96231b3b80d8