MIOperands/ConstMIOperands are classes iterating over the MachineOperand
of a MachineInstr, however MachineInstr::mop_iterator does the same
thing.
I assume these two iterators exist to have a uniform interface to
iterate over the operands of a machine instruction bundle and a single
machine instruction. However in practice I find it more confusing to have 2
different iterator classes, so this patch transforms (nearly all) the
code to use mop_iterators.
The only exception being MIOperands::anlayzePhysReg() and
MIOperands::analyzeVirtReg() still needing an equivalent, I leave that
as an exercise for the next patch.
Differential Revision: http://reviews.llvm.org/D9932
This version is slightly modified from the proposed revision in that it
introduces MachineInstr::getOperandNo to avoid the extra counting
variable in the few loops that previously used MIOperands::getOperandNo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238539 91177308-0d34-0410-b5e6-96231b3b80d8
TargetRegisterInfo::getRegPressureLimit has a note that it is an old
model that relies on manually entered classes. Using the newer model of
register pressure sets seems more appropriate. We might eventually even
switch to lib/CodeGen/RegisterPressure.cpp, but we should probably do
incremental changes here.
Using the newer model also makes it easier to take regmasks into account
which is necessary to fix llvm.org/PR23143. I am currently also
preparing a patch for that, but would like to do this switch
independently.
Review: http://reviews.llvm.org/D8986
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234880 91177308-0d34-0410-b5e6-96231b3b80d8
There were four almost identical implementations of calculating/updating
the register pressure for a certain MachineInstr. Cleanup to have a
single implementation (well, controlled with two bool flags until this
is cleaned up more).
No functional changes intended.
Tested by verify that there are no binary changes in the entire llvm
test-suite. A new test was added separately in r234309 as it revealed a
pre-existing error in the register pressure calculation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234325 91177308-0d34-0410-b5e6-96231b3b80d8
Specifically, if there are copy-like instructions in the loop header
they are moved into the loop close to their uses. This reduces the live
intervals of the values and can avoid register spills.
This is working towards a fix for http://llvm.org/PR22230.
Review: http://reviews.llvm.org/D7259
Next steps:
- Find a better cost model (which non-copy instructions should be sunk?)
- Make this dependent on register pressure
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232262 91177308-0d34-0410-b5e6-96231b3b80d8
Specifically:
- Calculate the loop pre-header once at the stat of HoistOutOfLoop, so:
- We don't-DFS walk the MachineDomTree if we aren't going to do anything
- Don't call getCurPreheader for each Scope
- Don't needlessly use a do-while loop
- Use early exit for Scopes.size() == 0
No functional changes intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228350 91177308-0d34-0410-b5e6-96231b3b80d8
Add a command-line option to enable hoisting even cheap instructions (in
low-register-pressure situations). This is turned off by default, but has
proved useful for testing purposes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225470 91177308-0d34-0410-b5e6-96231b3b80d8
This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.
This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222334 91177308-0d34-0410-b5e6-96231b3b80d8
define below all header includes in the lib/CodeGen/... tree. While the
current modules implementation doesn't check for this kind of ODR
violation yet, it is likely to grow support for it in the future. It
also removes one layer of macro pollution across all the included
headers.
Other sub-trees will follow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&. At this point they almost behave like normal iterators!
Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203865 91177308-0d34-0410-b5e6-96231b3b80d8
Post-RA LICM keeps three sets of registers: PhysRegDefs, PhysRegClobbers
and TermRegs. When it sees a definition of R it adds all aliases of R
to the corresponding set, so that when it needs to test for membership
it only needs to test a single register, rather than worrying about
aliases there too. E.g. the final candidate loop just has:
unsigned Def = Candidates[i].Def;
if (!PhysRegClobbers.test(Def) && ...) {
to test whether register Def is multiply defined.
However, there was also a shortcut in ProcessMI to make sure we didn't
add candidates if we already knew that they would fail the final test.
This shortcut was more pessimistic than the final one because it
checked whether _any alias_ of the defined register was multiply defined.
This is too conservative for targets that define register pairs.
E.g. on z, R0 and R1 are sometimes used as a pair, so there is a
128-bit register that aliases both R0 and R1. If a loop used
R0 and R1 independently, and the definition of R0 came first,
we would be able to hoist the R0 assignment (because that used
the final test quoted above) but not the R1 assignment (because
that meant we had two definitions of the paired R0/R1 register
and would fail the shortcut in ProcessMI).
This patch just uses the same check for the ProcessMI shortcut as
we use in the final candidate loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188774 91177308-0d34-0410-b5e6-96231b3b80d8
Matthias Braun
Daniel Jasper
Hal Finkel
David Blaikie
Eric Christopher
Benjamin Kramer
Jiangning Liu
Chandler Carruth
Nick Lewycky
Craig Topper
Paul Robinson
Owen Anderson
Richard Sandiford