Shuffles that only move an element into position 0 of the vector are common in
the output of the loop vectorizer and often generate suboptimal code when SSSE3
is not available. Lower them to vector shifts if possible.

We still prefer palignr over psrldq because it has higher throughput on
sandybridge.

llvm-svn: 182102

X86ISelLowering has support to treat:
(icmp ne (and (xor %flags, -1), (shl 1, flag)), 0)

as if it were actually:
(icmp eq (and %flags, (shl 1, flag)), 0)

However, r179386 has code at the InstCombine level to handle this.

llvm-svn: 181145

llvm-svn: 181136

llvm-svn: 180915

No functionality change

llvm-svn: 180914

No functionality change

llvm-svn: 180912

I think it's almost impossible to fold atomic fences profitably under
LLVM/C++11 semantics. As a result, this is now unused and just
cluttering up the target interface.

llvm-svn: 179940

llvm-svn: 179939

llvm-svn: 179901

llvm-svn: 179833

This pattern started popping up in vectorized min/max reductions.

llvm-svn: 179797

As packed comparisons in AVX/SSE produce all 0s or all 1s in each SIMD lane,
vector select could be simplified to AND/OR or removed if one or both values
being selected is all 0s or all 1s.

llvm-svn: 179267

This patch is revised based on patch from Victor Umansky
<victor.umansky@intel.com>. More cases are handled in X86's bool
simplification, i.e.
- SETCC_CARRY
- value is truncated to i1 with AND

As a by-product, PR5443 is also fixed.

llvm-svn: 179265

xmm0 / xmm1.

rdar://13599493

llvm-svn: 179141

During LTO, the target options on functions within the same Module may
change. This would necessitate resetting some of the back-end. Do this for X86,
because it's a Friday afternoon.

llvm-svn: 178917

A vector sext + sitofp is a lot cheaper than 8 scalar conversions.

llvm-svn: 178448

It was superseded by MachineBlockPlacement and disabled by default since LLVM 3.1.

llvm-svn: 178349

llvm-svn: 178314

- RDRAND always clears the destination value when a random value is not
  available (i.e. CF == 0). This value is truncated or zero-extended as
  the false boolean value to be returned. Boolean simplification needs
  to skip this 'zext' or 'trunc' node.

llvm-svn: 178312

To enable a load of a call address to be folded with that call, this
load is moved from outside of callseq into callseq. Such a moving
adds a non-glued node (that load) into a glued sequence. This non-glue
load is only removed when DAG selection folds them into a memory form
call instruction. When such instruction selection is disabled, it breaks
DAG schedule.

To prevent that, such moving is disabled when target favors register
indirect call.

Previous workaround disabling CALL32m/CALL64m insn selection is removed.

llvm-svn: 178308

llvm-svn: 178291

For the current Atom processor, the fastest way to handle a call
indirect through a memory address is to load the memory address into
a register and then call indirect through the register.

This patch implements this improvement by modifying SelectionDAG to
force a function address which is a memory reference to be loaded
into a virtual register.

Patch by Sriram Murali.

llvm-svn: 178171

Thanks to Bill Schmidt for pointing this out during code review!

llvm-svn: 178170

llvm-svn: 178083

- It's still considered aligned when the specified alignment is larger
  than the natural alignment;
- The new alignment for the high 128-bit vector should be min(16,
  alignment) as the pointer is advanced by 16, a power-of-2 offset.

llvm-svn: 177947

- Move SRA/SRL/SHL lowering support from DAG combination to DAG lowering
  to support extended 256-bit integer in AVX but not AVX2.

llvm-svn: 177478

- Prepare moving logic from DAG combining into DAG lowering. There's no
  functionality change.

llvm-svn: 177477

- no functionality change

llvm-svn: 177476

Patch by Ahmad, Muhammad T <muhammad.t.ahmad@intel.com>

llvm-svn: 177421

MinGW is almost completely compatible to MSVC, with the exception of the _tls_array global not being available.

Patch by David Nadlinger!

llvm-svn: 177257

- Fix the typo on type checking

llvm-svn: 177010

LegalizeDAG.cpp uses the value of the comparison operands when checking
the legality of BR_CC, so DAGCombiner should do the same.

v2:
  - Expand more BR_CC value types for NVPTX

v3:
  - Expand correct BR_CC value types for Hexagon, Mips, and XCore.

llvm-svn: 176694

That can usually be lowered efficiently and is common in sandybridge code.
It would be nice to do this in DAGCombiner but we can't insert arbitrary
BUILD_VECTORs this late.

Fixes PR15462.

llvm-svn: 176634

- Phi nodes should be replaced/updated after lowering CMOV into branch
  because 'mainMBB' updating operand in Phi node is changed.
- Add EFLAGS in livein before lowering the 2nd CMOV. It's necessary as
  we will reuse the EFLAGS generated before the 1st lowered CMOV, which
  won't clobber EFLAGS. However, we need explicitly specify that.
- '-attr=-cmov' test case are added.

llvm-svn: 176598

- Clear 'mayStore' flag when loading from the atomic variable before the
  spin loop
- Clear kill flag from one use to multiple use in registers forming the
  address to that atomic variable
- don't use a physical register as live-in register in BB (neither entry
  nor landing pad.) by copying it into virtual register

(patch by Cameron Zwarich)

llvm-svn: 176538

* Only apply divide bypass optimization when not optimizing for size. 
* Fixed bug caused by constant for 0 value of type Int32,
  used dividend type to generate the constant instead.
* For atom x86-64 apply the divide bypass to use 16-bit divides instead of
  64-bit divides when operand values are small enough.
* Added lit tests for 64-bit divide bypass.

Patch by Tyler Nowicki!

llvm-svn: 176442

- ISD::SHL/SRL/SRA must have either both scalar or both vector operands
  but TLI.getShiftAmountTy() so far only return scalar type. As a
  result, backend logic assuming that breaks.
- Rename the original TLI.getShiftAmountTy() to
  TLI.getScalarShiftAmountTy() and re-define TLI.getShiftAmountTy() to
  return target-specificed scalar type or the same vector type as the
  1st operand.
- Fix most TICG logic assuming TLI.getShiftAmountTy() a simple scalar
  type.

llvm-svn: 176364

- Put expensive checking after simple one

llvm-svn: 176060

- Check whether SSE is available before lowering all 1s vector building with
  PCMPEQD, which is only available from SSE2

llvm-svn: 176058

Fix PR15239.

llvm-svn: 175985