This is impossible in theory, I can prove it. In practice, our near-zero
threshold can cause the network to oscillate between equally good
solutions.
<rdar://problem/9720596>
llvm-svn: 134428
If the function allocates reserved stack space for callee argument frames,
estimateStackSize() needs to account for that, as it doesn't show up as
ordinary frame objects. Otherwise, a callee with a large argument list will
throw off the calculations for whether to allocate an emergency spill slot
and we get assert() failures in the register scavenger.
rdar://9715469
llvm-svn: 134415
Remat during spilling triggers dead code elimination. If a phi-def
becomes unused, that may also cause live ranges to split into separate
connected components.
This type of splitting is different from normal live range splitting. In
particular, there may not be a common original interval.
When the split range is its own original, make sure that the new
siblings are also their own originals. The range being split cannot be
used as an original since it doesn't cover the new siblings.
llvm-svn: 134413
Remove the assert that triggers if SuccIterator is constructed for a basic block
without a terminator instruction. Instead of triggering an assert a succ_end()
iterator is returned. This models a basic block with zero successors and allows
us to use F->viewCFG() on incompletely constructed functions.
llvm-svn: 134398
This fixes the issue noted in PR10251 where early tail dup of bbs with
indirectbr would cause a bb to be duplicated into a loop preheader
and then into its predecessors, creating phi nodes with identical
operands just before register allocation.
This helps with jsinterp.o size (__TEXT goes from 163568 to 126656)
and a bit with performance 1.005x faster on sunspider (jits still enabled).
The result on webkit with the jit disabled is more significant: 1.021x faster.
llvm-svn: 134372
A split point inserted in a block with a landing pad successor may be
hoisted above the call to ensure that it dominates all successors. The
code that handles the rest of the basic block must take this into
account.
I am not including a test case, it would be very fragile. PR10244 comes
from building clang with exceptions enabled.
llvm-svn: 134369
