Drive-by improvement: We would 1) add CSRs, 2) remove callee saved CSRs
and 3) add all CSRs again for the return block. Just adding CSRs once
obviously gives the same results.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274955 91177308-0d34-0410-b5e6-96231b3b80d8
findScratchNonCalleeSaveRegister() just needs a simple liveness
analysis, use LivePhysRegs for that as it is simpler and does not depend
on the kill flags.
This commit adds a convenience function available() to LivePhysRegs:
This function returns true if the given register is not reserved and
neither the register nor any of its aliases are alive.
Differential Revision: http://reviews.llvm.org/D21865
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274685 91177308-0d34-0410-b5e6-96231b3b80d8
Remove the AddPristinesAndCSRs parameters from
addLiveIns()/addLiveOuts().
We need to respect pristine registers after prologue epilogue insertion,
Seeing that we got this wrong in at least two commits already, we should
rather pay the small price to query MachineFrameInfo for it.
There are three cases that did not set AddPristineAndCSRs to true even
after register allocation:
- ExecutionDepsFix: live-out registers are used as a hint that the
register is used soon. This is not true for pristine registers so
use the new addLiveOutsNoPristines() to maintain this behaviour.
- SystemZShortenInst: Not setting AddPristineAndCSRs to true looks like
a bug, should do the right thing automatically now.
- StackMapLivenessAnalysis: Not adding pristine registers looks like a
bug to me. Added a FIXME comment but maintain the current behaviour
as a change may need to get coordinated with GC runtimes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268336 91177308-0d34-0410-b5e6-96231b3b80d8
Update APIs in MachineInstrBundle.h to take and return MachineInstr&
instead of MachineInstr* when the instruction cannot be null. Besides
being a nice cleanup, this is tacking toward a fix for PR26753.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262141 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The testing for returnBB was flipped which may cause ARM ld/st opt pass uses callee saved regs in returnBB when shrink-wrap is used.
Reviewers: t.p.northover, apazos, MatzeB
Subscribers: mcrosier, zzheng, aemerson, llvm-commits, rengolin
Differential Revision: http://reviews.llvm.org/D16434
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258569 91177308-0d34-0410-b5e6-96231b3b80d8
I realized that the live-out set computed for the return block is
missing the callee saved registers (the non-pristine ones to be exact).
This only affects the liveness computed for instructions inside the
function epilogue which currently none of the LivePhysRegs users in llvm
cares about, so this is just a drive-by fix without a testcase.
Differential Revision: http://reviews.llvm.org/D13180
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248636 91177308-0d34-0410-b5e6-96231b3b80d8
With subregister liveness enabled we can detect the case where only
parts of a register are live in, this is expressed as a 32bit lanemask.
The current code only keeps registers in the live-in list and therefore
enumerated all subregisters affected by the lanemask. This turned out to
be too conservative as the subregister may also cover additional parts
of the lanemask which are not live. Expressing a given lanemask by
enumerating a minimum set of subregisters is computationally expensive
so the best solution is to simply change the live-in list to store the
lanemasks as well. This will reduce memory usage for targets using
subregister liveness and slightly increase it for other targets
Differential Revision: http://reviews.llvm.org/D12442
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247171 91177308-0d34-0410-b5e6-96231b3b80d8
We had code such as this:
r2 = ...
t2Bcc
label1:
ldr ... r2
label2;
return r2<dead, def>
The if converter was transforming this to
r2<def> = ...
return [pred] r2<dead,def>
ldr <r2, kill>
return
which fails the machine verifier because the ldr now reads from a dead def.
The fix here detects dead defs in stepForward and passes them back to the caller in the clobbers list. The caller then clears the dead flag from the def is the value is live.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236660 91177308-0d34-0410-b5e6-96231b3b80d8
Note, this is a reapplication of r236515 with a fix to not assert on non-register operands, but instead only handle them until the subsequent commit. Original commit message follows.
The code was basically the same here already. Just added an out parameter for a vector of seen defs so that UpdatePredRedefs can call StepForward first, then do its own post processing on the seen defs.
Will be used in the next commit to also handle regmasks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236538 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit 963cdbccf6e5578822836fd9b2ebece0ba9a60b7 (ie r236514)
This is to get the bots green while i investigate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236518 91177308-0d34-0410-b5e6-96231b3b80d8
The code was basically the same here already. Just added an out parameter for a vector of seen defs so that UpdatePredRedefs can call StepForward first, then do its own post processing on the seen defs.
Will be used in the next commit to also handle regmasks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236514 91177308-0d34-0410-b5e6-96231b3b80d8
