chain operand to point to the load being folded. Now we relax this, traversing
up the chain, if it doesn't reach the load, then it's ok. We will create a
TokenFactor (of all the chain operands and the load's chain) to capture all
the control flow dependencies.
llvm-svn: 30897
The dag/inst combiners often 'simplify' the masked value based on whether
or not the bits are live or known zero/one. This is good and dandy, but
often causes special case patterns to fail, such as alpha's CMPBGE pattern,
which looks like "(set GPRC:$RC, (setuge (and GPRC:$RA, 255), (and GPRC:$RB, 255)))".
Here the pattern for (and X, 255) should match actual dags like (and X, 254) if
the dag combiner proved that the missing bits are already zero (one for 'or').
For CodeGen/Alpha/cmpbge.ll:test2 for example, this results in:
sll $16,1,$0
cmpbge $0,$17,$0
ret $31,($26),1
instead of:
sll $16,1,$0
and $0,254,$0
and $17,255,$1
cmpule $1,$0,$0
ret $31,($26),1
... and requires no target-specific code.
llvm-svn: 30871
AggregateString += "\0\0";
Doesn't add two nuls to the AggregateString (for obvious reasons), which
broke the asmprinter when the first character of an asm string was not
literal text.
llvm-svn: 30625
the branch's chain is also produced by cmp.
[ch, r : ld]
^ ^
| |
[XX]--/ \- [flag : cmp]
^ ^
| |
\---[br flag]-
Remove an isel check which prevents loads from being folded into cmp / test
instructions.
2) Whenever possible, delete a selected node to allow more load folding
opportunities. Note not all nodes can be deleted after it has been
selected. Some may have simply morphed; some have not changed at all (e.g.
EntryToken).
llvm-svn: 30242
actually *removes* one of the operands, instead of just assigning both operands
the same register. This make reasoning about instructions unnecessarily complex,
because you need to know if you are before or after register allocation to match
up operand #'s with the target description file.
Changing this also gets rid of a bunch of hacky code in various places.
This patch also includes changes to fold loads into cmp/test instructions in
the X86 backend, along with a significant simplification to the X86 spill
folding code.
llvm-svn: 30108
- Clean up the code generated by tablegen:
* AddToISelQueue now takes one argument.
* ComplexPattern matching condition can now be shared.
* Eliminate passing unnecessary arguments to emit routines.
* Eliminate some unneeded SDOperand declarations in select routines.
* Other minor clean ups.
- This reduces foot print slightly: X86ISelDAGToDAG.o is reduced from 971k
to 823k.
llvm-svn: 29892
Reid Spencer