Summary:
Currently Thumb2InstrInfo.cpp uses a register class which is
auto-generated by tablegen. Such approach is fragile because
auto-generated classes might change when other register classes are
added. For example, before https://reviews.llvm.org/D62667
we were using GPRPair_with_gsub_1_in_rGPRRegClass, but had to
change it to GPRPair_with_gsub_1_in_GPRwithAPSRnospRegClass
because the former class stopped being generated (this did not change
the functionality though).
This patch adds a register class consisting of even-odd GPR register
pairs from (R0, R1) to (R10, R11), which excludes (R12, SP) and uses
it in Thumb2InstrInfo.cpp instead of
GPRPair_with_gsub_1_in_GPRwithAPSRnospRegClass.
Reviewers: ostannard, simon_tatham, dmgreen, efriedma
Reviewed By: simon_tatham
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69026
llvm-svn: 374990
I'm not sure if it's worth it or not to add a hook to disable the pass
for an arbitrary function.
This pass is taking up to 5% of compile time in tiny programs by
iterating through all of the physical registers in every register
class. This pass should be rewritten in terms of regunits. For now,
skip doing anything for entry point functions. The vast majority of
functions in the real world aren't callable, so just not running this
will give the majority of the benefit.
llvm-svn: 365255
This adds support for the new family of conditional selection /
increment / negation instructions; the low-overhead branch
instructions (e.g. BF, WLS, DLS); the CLRM instruction to zero a whole
list of registers at once; the new VMRS/VMSR and VLDR/VSTR
instructions to get data in and out of 8.1-M system registers,
particularly including the new VPR register used by MVE vector
predication.
To support this, we also add a register name 'zr' (used by the CSEL
family to force one of the inputs to the constant 0), and operand
types for lists of registers that are also allowed to include APSR or
VPR (used by CLRM). The VLDR/VSTR instructions also need a new
addressing mode.
The low-overhead branch instructions exist in their own separate
architecture extension, which we treat as enabled by default, but you
can say -mattr=-lob or equivalent to turn it off.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Reviewed By: samparker
Subscribers: miyuki, javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62667
llvm-svn: 363039
These caused a build failure because I managed not to notice they
depended on a later unpushed commit in my current stack. Sorry about
that.
llvm-svn: 362956
This adds support for the new family of conditional selection /
increment / negation instructions; the low-overhead branch
instructions (e.g. BF, WLS, DLS); the CLRM instruction to zero a whole
list of registers at once; the new VMRS/VMSR and VLDR/VSTR
instructions to get data in and out of 8.1-M system registers,
particularly including the new VPR register used by MVE vector
predication.
To support this, we also add a register name 'zr' (used by the CSEL
family to force one of the inputs to the constant 0), and operand
types for lists of registers that are also allowed to include APSR or
VPR (used by CLRM). The VLDR/VSTR instructions also need some new
addressing modes.
The low-overhead branch instructions exist in their own separate
architecture extension, which we treat as enabled by default, but you
can say -mattr=-lob or equivalent to turn it off.
Reviewers: dmgreen, samparker, SjoerdMeijer, t.p.northover
Reviewed By: samparker
Subscribers: miyuki, javed.absar, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62667
llvm-svn: 362953
To determine the list of clobbered registers, the RegUsageInfoCollector pass
uses the list of callee saved registers provided by the target and then augments
it with the list of registers which have all their subregisters saved. It then
basically does the difference between all the registers and the saved registers
to come up with what is clobbered (plus it checks that the register is defined
within that functions).
The patch fixes a bug where when register does not have any subregister lane,
hence when checking if any of its subregister are not saved, we would find none
and think the register is saved as well.
That's obviously wrong.
The code was actually kind of checking for something like that with the
CoveredBySubRegs bit. What this bit says is that a register is completely
covered by its subregisters.
We required that this bit was set, to check that a register was saved by its
subregister lanes, since without this bit, we potentially would miss to check
some part of the register.
However, this bit is used de facto on registers that don't have any
subregisters (e.g., on ARM) and the code was not prepared for that.
This patch fixes this by checking that a register has subregisters before
declaring it saved when none of its lanes are modified.
llvm-svn: 361901
Mikhail Maltsev