Sicne MBB->computeRegisterLivenes() returns Dead for sub regs like s0,
d0 is used in vpop instead of updating sp, which causes s0 dead before
its use.
This patch checks the liveness of each subreg to make sure the reg is
actually dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204411 91177308-0d34-0410-b5e6-96231b3b80d8
The changes caused by folding an sp-adjustment into a "pop" previously
disrupted the forward search for the final real instruction in a
terminating block. This switches to a backward search (skipping debug
instrs).
This fixes PR18399.
Patch by Zhaoshi.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199266 91177308-0d34-0410-b5e6-96231b3b80d8
The ARM backend has been using most of the MachO related subtarget
checks almost interchangeably, and since the only target it's had to
run on has been IOS (which is all three of MachO, Darwin and IOS) it's
worked out OK so far.
But we'd like to support embedded targets under the "*-*-none-macho"
triple, which means everything starts falling apart and inconsistent
behaviours emerge.
This patch should pick a reasonably sensible set of behaviours for the
new triple (and any others that come along, with luck). Some choices
were debatable (notably FP == r7 or r11), but we can revisit those
later when deficiencies become apparent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198617 91177308-0d34-0410-b5e6-96231b3b80d8
When trying to eliminate an "sub sp, sp, #N" instruction by folding
it into an existing push/pop using dummy registers, we need to account
for the fact that this might affect precisely how "fp" gets set in the
prologue.
We were attempting this, but assuming that *whenever* we performed a
fold it would make a difference. This is false, for example, in:
push {r4, r7, lr}
add fp, sp, #4
vpush {d8}
sub sp, sp, #8
we can fold the "sub" into the "vpush", forming "vpush {d7, d8}".
However, in that case the "add fp" instruction mustn't change, which
we were getting wrong before.
Should fix PR18160.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196725 91177308-0d34-0410-b5e6-96231b3b80d8
We were trying to fold the stack adjustment into the wrong instruction in the
situation where the entire basic-block was epilogue code. Really, it can only
ever be valid to do the folding precisely where the "add sp, ..." would be
placed so there's no need for a separate iterator to track that.
Should fix PR18136.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196493 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, we clobbered callee-saved registers when folding an "add
sp, #N" into a "pop {rD, ...}" instruction. This change checks whether
a register we're going to add to the "pop" could actually be live
outside the function before doing so and should fix the issue.
This should fix PR18081.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196046 91177308-0d34-0410-b5e6-96231b3b80d8
ARM prologues usually look like:
push {r7, lr}
sub sp, sp, #4
If code size is extremely important, this can be optimised to the single
instruction:
push {r6, r7, lr}
where we don't actually care about the contents of r6, but pushing it subtracts
4 from sp as a side effect.
This should implement such a conversion, predicated on the "minsize" function
attribute (-Oz) since I've yet to find any code it actually makes faster.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194264 91177308-0d34-0410-b5e6-96231b3b80d8
