numbering values in live ranges for physical registers.
The alpha backend currently generates code that looks like this:
vreg = preg
...
preg = vreg
use preg
...
preg = vreg
use preg
etc. Because vreg contains the value of preg coming in, each of the
copies back into preg contain that initial value as well.
In the case of the Alpha, this allows this testcase:
void "foo"(int %blah) {
store int 5, int *%MyVar
store int 12, int* %MyVar2
ret void
}
to compile to:
foo:
ldgp $29, 0($27)
ldiq $0,5
stl $0,MyVar
ldiq $0,12
stl $0,MyVar2
ret $31,($26),1
instead of:
foo:
ldgp $29, 0($27)
bis $29,$29,$0
ldiq $1,5
bis $0,$0,$29
stl $1,MyVar
ldiq $1,12
bis $0,$0,$29
stl $1,MyVar2
ret $31,($26),1
This does not seem to have any noticable effect on X86 code.
This fixes PR535.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20536 91177308-0d34-0410-b5e6-96231b3b80d8
Make only one print method to avoid overloaded virtual warnings when \
compiled with -Woverloaded-virtual
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18589 91177308-0d34-0410-b5e6-96231b3b80d8
it was a use, def, or both. This allows us to be less pessimistic in our
analysis of them. In practice, this doesn't make a big difference, but it
doesn't hurt either.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16632 91177308-0d34-0410-b5e6-96231b3b80d8
* Add const_iterator stuff
* Add a print method, which means that I can now call dump() from the
debugger.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16612 91177308-0d34-0410-b5e6-96231b3b80d8
Move include/Config and include/Support into include/llvm/Config,
include/llvm/ADT and include/llvm/Support. From here on out, all LLVM
public header files must be under include/llvm/.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16137 91177308-0d34-0410-b5e6-96231b3b80d8
Regression.CodeGen.Generic.2004-04-09-SameValueCoalescing.llx and the
code size problem.
This bug prevented us from doing most register coallesces.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16031 91177308-0d34-0410-b5e6-96231b3b80d8
same as the PHI use. This is not correct as the PHI use value is different
depending on which branch is taken. This fixes espresso with aggressive
coallescing, and perhaps others.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15189 91177308-0d34-0410-b5e6-96231b3b80d8
LiveInterval>. This saves some space and removes the pointer
indirection caused by following the pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15167 91177308-0d34-0410-b5e6-96231b3b80d8
Interval. This generalizes the isDefinedOnce mechanism that we used before
to help us coallesce ranges that overlap. As part of this, every logical
range with a different value is assigned a different number in the interval.
For example, for code that looks like this:
0 X = ...
4 X += ...
...
N = X
We now generate a live interval that contains two ranges: [2,6:0),[6,?:1)
reflecting the fact that there are two different values in the range at
different positions in the code.
Currently we are not using this information at all, so this just slows down
liveintervals. In the future, this will change.
Note that this change also substantially refactors the joinIntervalsInMachineBB
method to merge the cases for virt-virt and phys-virt joining into a single
case, adds comments, and makes the code a bit easier to follow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15154 91177308-0d34-0410-b5e6-96231b3b80d8
* Inline some functions
* Eliminate some comparisons from the release build
This is good for another .3 on gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15144 91177308-0d34-0410-b5e6-96231b3b80d8
will soon be renamed) into their own file. The new file should not emit
DEBUG output or have other side effects. The LiveInterval class also now
doesn't know whether its working on registers or some other thing.
In the future we will want to use the LiveInterval class and friends to do
stack packing. In addition to a code simplification, this will allow us to
do it more easily.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15134 91177308-0d34-0410-b5e6-96231b3b80d8
Use an explicit LiveRange class to represent ranges instead of an std::pair.
This is a minor cleanup, but is really intended to make a future patch simpler
and less invasive.
Alkis, could you please take a look at LiveInterval::liveAt? I suspect that
you can add an operator<(unsigned) to LiveRange, allowing us to speed up the
upper_bound call by quite a bit (this would also apply to other callers of
upper/lower_bound). I would do it myself, but I still don't understand that
crazy liveAt function, despite the comment. :)
Basically I would like to see this:
LiveRange dummy(index, index+1);
Ranges::const_iterator r = std::upper_bound(ranges.begin(),
ranges.end(),
dummy);
Turn into:
Ranges::const_iterator r = std::upper_bound(ranges.begin(),
ranges.end(),
index);
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15130 91177308-0d34-0410-b5e6-96231b3b80d8
interfere. Because these intervals have a single definition, and one of them
is a copy instruction, they are always safe to merge even if their lifetimes
interfere. This slightly reduces the amount of spill code, for example on
252.eon, from:
12837 spiller - Number of loads added
7604 spiller - Number of stores added
5842 spiller - Number of register spills
18155 liveintervals - Number of identity moves eliminated after coalescing
to:
12754 spiller - Number of loads added
7585 spiller - Number of stores added
5803 spiller - Number of register spills
18262 liveintervals - Number of identity moves eliminated after coalescing
The much much bigger win would be to merge intervals with multiple definitions
(aka phi nodes) but this is not that day.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15124 91177308-0d34-0410-b5e6-96231b3b80d8
intervals need not be sorted anymore. Removing this redundant step
improves LiveIntervals running time by 5% on 176.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15106 91177308-0d34-0410-b5e6-96231b3b80d8
fortunately, they are easy to handle if we know about them. This patch fixes
some serious pessimization of code produced by the linscan register allocator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15092 91177308-0d34-0410-b5e6-96231b3b80d8
is a simple change, but seems to improve code a little. For example, on
256.bzip2, we went from 75.0s -> 73.33s (2% speedup).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15004 91177308-0d34-0410-b5e6-96231b3b80d8
* vreg <-> vreg joining now works, enable it unconditionally when joining
is enabled (which is the default).
* Fix a serious pessimization of spill code where we were saying that a
spilled DEF operand was live into the subsequent instruction. This allows
for substantially better code when spilling starts to happen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14993 91177308-0d34-0410-b5e6-96231b3b80d8
order, causing the inactive list in the linearscan list to get unsorted, which
basically fuxored everything up severely.
These seems to fix the joiner, so with more testing I will enable it by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14992 91177308-0d34-0410-b5e6-96231b3b80d8
Heavily refactor handleVirtualRegisterDef, adding comments and making it more
efficient. It is also much easier to follow and convince ones self that it is
correct :)
Add -debug output to the joine, showing the result of joining the intervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14989 91177308-0d34-0410-b5e6-96231b3b80d8
1. LiveIntervals now implement a 4 slot per instruction model. Load,
Use, Def and a Store slot. This is required in order to correctly
represent caller saved register clobbering on function calls,
register reuse in the same instruction (def resues last use) and
also spill code added later by the allocator. The previous
representation (2 slots per instruction) was insufficient and as a
result was causing subtle bugs.
2. Fixes in spill code generation. This was the major cause of
failures in the test suite.
3. Linear scan now has core support for folding memory operands. This
is untested and not enabled (the live interval update function does
not attempt to fold loads/stores in instructions).
4. Lots of improvements in the debugging output of both live intervals
and linear scan. Give it a try... it is beautiful :-)
In summary the above fixes all the issues with the recent reserved
register elimination changes and get the allocator very close to the
next big step: folding memory operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11654 91177308-0d34-0410-b5e6-96231b3b80d8
ilist of MachineInstr objects. This allows constant time removal and
insertion of MachineInstr instances from anywhere in each
MachineBasicBlock. It also allows for constant time splicing of
MachineInstrs into or out of MachineBasicBlocks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11340 91177308-0d34-0410-b5e6-96231b3b80d8
slots each. As a concequence they get numbered as 0, 2, 4 and so
on. The first slot is used for operand uses and the second for
defs. Here's an example:
0: A = ...
2: B = ...
4: C = A + B ;; last use of A
The live intervals should look like:
A = [1, 5)
B = [3, x)
C = [5, y)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11141 91177308-0d34-0410-b5e6-96231b3b80d8
of a linear search to find the first range for comparisons. This cuts
down the linear scan register allocator running time by a factor of 3
in 254.perlbmk and by a factor of 2.2 in 176.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11030 91177308-0d34-0410-b5e6-96231b3b80d8
Simplification of LiveIntervals::Interval::overlaps() and addition of
examples to overlaps() and liveAt() to make them clearer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11028 91177308-0d34-0410-b5e6-96231b3b80d8
when joining we need to check if we overlap with the second interval
or any of its aliases.
Also make joining intervals the default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10973 91177308-0d34-0410-b5e6-96231b3b80d8
is a move between two registers, at least one of the registers is
virtual and the two live intervals do not overlap.
This results in about 40% reduction in intervals, 30% decrease in the
register allocators running time and a 20% increase in peephole
optimizations (mainly move eliminations).
The option can be enabled by passing -join-liveintervals where
appropriate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10965 91177308-0d34-0410-b5e6-96231b3b80d8
LiveIntervals::Interval::liveAt. Both were considering the live ranges
closed in the end, when they are actually open.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10835 91177308-0d34-0410-b5e6-96231b3b80d8
when an implicitely defined register is later used by an alias. For example:
call foo
%reg1024 = mov %AL
The call implicitely defines EAX but only AL is used. Before this fix
no information was available on AL. Now EAX and all its aliases except
AL get defined and die at the call instruction whereas AL lives to be
killed by the assignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10813 91177308-0d34-0410-b5e6-96231b3b80d8
which denotes the register we would like to be assigned to (virtual or
physical). In register allocation, if this hint exists and we can map
it to a physical register (it is either a physical register or it is a
virtual register that already got assigned to a physical one) we use
that register if it is available instead of a random one in the free
pool.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10634 91177308-0d34-0410-b5e6-96231b3b80d8
with live intervals was missing registers that were used before they
were defined (in the arbitrary order live intervals numbers
instructions).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10603 91177308-0d34-0410-b5e6-96231b3b80d8
nesting level when computing it. Right now the allocator uses:
w = sum_over_defs_uses( 10 ^ nesting level );
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10569 91177308-0d34-0410-b5e6-96231b3b80d8
instruction pass. This also fixes all remaining bugs for this new
allocator to pass all tests under test/Programs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10515 91177308-0d34-0410-b5e6-96231b3b80d8
killing instruction is tracked. This causes the LiveIntervals to
create bogus intervals. The workaound is to add a range to the
interval from the redefinition to the end of the basic block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10510 91177308-0d34-0410-b5e6-96231b3b80d8
Move some of the longer LiveIntervals::Interval method out of the
header and add debug information to them. Fix bug and simplify range
merging code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10509 91177308-0d34-0410-b5e6-96231b3b80d8
a) remove opIsUse(), opIsDefOnly(), opIsDefAndUse()
b) add isUse(), isDef()
c) rename opHiBits32() to isHiBits32(),
opLoBits32() to isLoBits32(),
opHiBits64() to isHiBits64(),
opLoBits64() to isLoBits64().
This results to much more readable code, for example compare
"op.opIsDef() || op.opIsDefAndUse()" to "op.isDef()" a pattern used
very often in the code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10461 91177308-0d34-0410-b5e6-96231b3b80d8
