1. (((x) & 0xFF00) >> 8) | (((x) & 0x00FF) << 8)
=> (bswap x) >> 16
2. ((x&0xff)<<8)|((x&0xff00)>>8)|((x&0xff000000)>>8)|((x&0x00ff0000)<<8))
=> (rotl (bswap x) 16)
This allows us to eliminate most of the def : Pat patterns for ARM rev16
revsh instructions. It catches many more cases for ARM and x86.
rdar://9609108
llvm-svn: 133503
ops.
This is a rewrite of the IV simplification algorithm used by
-disable-iv-rewrite. To avoid perturbing the default mode, I
temporarily split the driver and created SimplifyIVUsersNoRewrite. The
idea is to avoid doing opcode/pattern matching inside
IndVarSimplify. SCEV already does it. We want to optimize with the
full generality of SCEV, but optimize def-use chains top down on-demand rather
than rewriting the entire expression bottom-up. This was easy to do
for operations that SCEV can prove are identity function. So we're now
eliminating bitmasks and zero extends this way.
A result of this rewrite is that indvars -disable-iv-rewrite no longer
requires IVUsers.
llvm-svn: 133502
The current implementation generates stack loads/stores, which are
really just mov instructions from/to "special" registers. This may
not be the most efficient implementation, compared to an approach where
the stack registers are directly folded into instructions, but this is
easier to implement and I have yet to see a case where ptxas is unable
to see through this kind of register usage and know what is really
going on.
llvm-svn: 133443
Change PHINodes to store simple pointers to their incoming basic blocks,
instead of full-blown Uses.
Note that this loses an optimization in SplitCriticalEdge(), because we
can no longer walk the use list of a BasicBlock to find phi nodes. See
the comment I removed starting "However, the foreach loop is slow for
blocks with lots of predecessors".
Extend replaceAllUsesWith() on a BasicBlock to also update any phi
nodes in the block's successors. This mimics what would have happened
when PHINodes were proper Users of their incoming blocks. (Note that
this only works if OldBB->replaceAllUsesWith(NewBB) is called when
OldBB still has a terminator instruction, so it still has some
successors.)
llvm-svn: 133435
Change various bits of code to make better use of the existing PHINode
API, to insulate them from forthcoming changes in how PHINodes store
their operands.
llvm-svn: 133434
I don't think the AugmentedUse struct buys us much, either in
correctness or in ease of use. Ditch it, and simplify Use::getUser() and
User::allocHungoffUses().
llvm-svn: 133433
* Don't introduce a duplicated bb in the CFG
* When making a branch unconditional, clear the PredCond array so that it
is really unconditional.
llvm-svn: 133432
dragonegg buildbots back to life. Original commit message:
Teach early dup how to duplicate basic blocks with one successor and only phi instructions
into more complex blocks.
llvm-svn: 133430
all over the place in different styles and variants. Standardize on two
preferred entrypoints: one that takes a StructType and ArrayRef, and one that
takes StructType and varargs.
In cases where there isn't a struct type convenient, we now add a
ConstantStruct::getAnon method (whose name will make more sense after a few
more patches land).
It would be "really really nice" if the ConstantStruct::get and
ConstantVector::get methods didn't make temporary std::vectors.
llvm-svn: 133412
A RegisterTuples instance is used to synthesize super-registers by
zipping together lists of sub-registers. This is useful for generating
pseudo-registers representing register sequence constraints like 'two
consecutive GPRs', or 'an even-odd pair of floating point registers'.
The RegisterTuples def can be used in register set operations when
building register classes. That is the only way of accessing the
synthesized super-registers.
For example, the ARM QQ register class of pseudo-registers could have
been formed like this:
// Form pairs Q0_Q1, Q2_Q3, ...
def QQPairs : RegisterTuples<[qsub_0, qsub_1],
[(decimate QPR, 2),
(decimate (shl QPR, 1), 2)]>;
def QQ : RegisterClass<..., (add QQPairs)>;
Similarly, pseudo-registers representing '3 consecutive D-regs with
wraparound' look like:
// Form D0_D1_D2, D1_D2_D3, ..., D30_D31_D0, D31_D0_D1.
def DSeqTriples : RegisterTuples<[dsub_0, dsub_1, dsub_2],
[(rotl DPR, 0),
(rotl DPR, 1),
(rotl DPR, 2)]>;
TableGen automatically computes aliasing information for the synthesized
registers.
Register tuples are still somewhat experimental. We still need to see
how they interact with MC.
llvm-svn: 133407
top level type without a specified number. This asmprinter has never
generated this, as you can tell by no tests being updated. It also isn't
documented.
llvm-svn: 133368
Jay Foad