partially unroll a loop when fully unrolling would not fit under the threshold.

Patch by Mikael Lepistö.

llvm-svn: 54160

that says "unconditional loads from this argument are safe", we now keep track
of the safety per set of indices from which loads happen. This prevents
ArgPromotion from promoting loads that aren't really valid. As an added effect,
this will now disregard the the type of the indices passed to a GEP, so
"load GEP %A, i32 1" and "load GEP %A, i64 1" will result in a single argument,
not two.

This fixes PR2598, for which a testcase has been added as well.

llvm-svn: 54159

llvm-svn: 54144

This fixes PR2599.

llvm-svn: 54133

llvm-svn: 54128

command-line option, and disable it by default. It introduced performance
regressions because CodeGen is currently not able to remat such loads.

llvm-svn: 53997

case for this.

This allows instructions like loads from global variables declared to
be constant to be moved out of loops."

Patch by Stefanus Du Toit!

llvm-svn: 53945

Remove the GetResultInst instruction. It is still accepted in LLVM assembly
and bitcode, where it is now auto-upgraded to ExtractValueInst. Also, remove
support for return instructions with multiple values. These are auto-upgraded
to use InsertValueInst instructions.

The IRBuilder still accepts multiple-value returns, and auto-upgrades them
to InsertValueInst instructions.

llvm-svn: 53941

leads into a cycle involving a different PHI, LSR got stuck running
around that cycle looking for the original PHI. To avoid this, keep
track of visited PHIs and stop searching if we see one more than once.
This fixes PR2570.

llvm-svn: 53879

llvm-svn: 53771

Make PRE actually handle critical edges (by splitting them).  Confirmed that bootstrap passes with this change.

llvm-svn: 53762

llvm-svn: 53761

llvm-svn: 53760

llvm-svn: 53757

llvm-svn: 53735

more than once.

llvm-svn: 53731

llvm-svn: 53730

llvm-svn: 53716

llvm-svn: 53715

llvm-svn: 53712

llvm-svn: 53705

could cause problems for memdep when it breaks critical edges.

llvm-svn: 53691

FindInsertedValue, it now performs a number of simple transformations that
should result in the same effect when applied iteratively.

llvm-svn: 53673

llvm-svn: 53666

llvm-svn: 53627

llvm-svn: 53616

Have GVN do a pre-pass over the CFG that folds away unconditional branches where possible.  This allows local PRE to be more aggressive.

llvm-svn: 53615

again canonicalizes {i32} into i32 and {} into void.

llvm-svn: 53610

return value as a whole in deadargelim is really not needed now that we simply
rebuild the old return value and actually prevents some canonicalization from
taking place.

This revert stops deadargelim from changing {i32} into i32 for now, but I'll
fix that next.

llvm-svn: 53609

return values that are still (partially) live. Instead of updating all uses of
a call instruction after removing some elements, it now just rebuilds the
original struct (With undef gaps where the unused values were) and leaves it to
instcombine to clean this up.

The added testcase still fails currently, but this is due to instcombine which
isn't good enough yet. I will fix that part next.

llvm-svn: 53608

llvm-svn: 53607

only the liveness of partial return values (for functions returning a struct).
This is more explicit to prevent unwanted changes in the return value. 

In particular, deadargelim now canonicalizes a function returning {i32} to
returning i32 and {} to void, if the struct returned is not used in its
entirety, but only the single element is used.

llvm-svn: 53606

and return values live for those functions. This doesn't change anything yet,
but prepares for the coming commits.

llvm-svn: 53601

llvm-svn: 53600

RetOrArg::getDescription() as const.

llvm-svn: 53599

llvm-svn: 53598

llvm-svn: 53592

method, to slightly simplify control flow.

llvm-svn: 53591

llvm-svn: 53564

llvm-svn: 53557