llvm-svn: 52466

Revert r52459, which was causing an infinite loop or massive slowdown on MultiSource/Applications/SPASS, and possibly others as well.
Please reapply once this is fixed.

llvm-svn: 52465

function, and make use of it in several places.

llvm-svn: 52463

dependencies between return values and/or arguments. Also make the handling of
arguments and return values the same.

The pass now looks properly inside returned structs, but only at the first                                                                                     
level (ie, not inside nested structs).

Also add a testcase for testing various variations of (multiple) dead rerturn
values.

llvm-svn: 52459

time. Sorry for the trouble!

This time, also add a testcase, which I should have done in the first place...

llvm-svn: 52455

commit after this).

llvm-svn: 52453

llvm-svn: 52442

implements rdar://6013816 and the testcase in Transforms/InstCombine/sext-misc.ll.

llvm-svn: 52440

llvm-svn: 52438

We don't want to find dependencies within the same block in this case.  It leads to incorrect results because
we're detecting something at or after the call we're querying on.

llvm-svn: 52433

llvm-svn: 52415

Spotted by Nick Lewycky.

llvm-svn: 52411

speaking these are not constant values. However, when a function always returns
one of its arguments, then from the point of view of each caller the return
value is constant (or at least a known value) and can be replaced.

llvm-svn: 52397

individually.

Also learn IPConstProp how returning first class aggregates work, in addition
to old style multiple return instructions.

Modify the return-constants testscase to confirm this behaviour.

llvm-svn: 52396

when changing the stride of a comparison so that it's slightly
more precise, by having it scan the instruction list to determine
if there is a use of the condition after the point where the
condition will be inserted.

llvm-svn: 52371

llvm-svn: 52361

llvm-svn: 52339

llvm-svn: 52318

llvm-svn: 52316

I'm at it, rename it to FindInsertedValue.

The only functional change is that newly created instructions are no longer
added to instcombine's worklist, but that is not really necessary anyway (and
I'll commit some improvements next that will completely remove the need).

llvm-svn: 52315

llvm-svn: 52295

llvm-svn: 52267

when trying to sink stores.

llvm-svn: 52259

for it to generate use-before-def IR, such as in this testcase.

llvm-svn: 52258

structure checks are incorrect if the blocks aren't distinct.
Fixes PR2435.

llvm-svn: 52257

llvm-svn: 52251

llvm-svn: 52247

llvm-svn: 52246

Do not speculatively execute an instruction by hoisting it to its predecessor BB if any of its operands are defined but not used in BB. The transformation will prevent the operand from being sunk into the use block.

llvm-svn: 52244

llvm-svn: 52243

llvm-svn: 52242

llvm-svn: 52226

For now, avoid generating FP select instructions in order to speculatively execute integer arithmetic instructions. FP selects are more likely to be expensive (even compared to branch on fcmp). This is not a wonderful solution but I rather err on the side of conservative.

This fixes the heapsort performance regressions.

llvm-svn: 52224

Avoid duplicating loop header which leads to unnatural loops (and just seem like general badness to me, likely to cause code explosion).
Patch by Florian Brandner.

llvm-svn: 52223

useless insert-extract chains, similar to how it folds them for vectors.

Add a testcase for this.

llvm-svn: 52217

llvm-svn: 52212

llvm-svn: 52191

llvm-svn: 52138

result of a weak function.

llvm-svn: 52137

of apint codegen failure is the DAG combiner doing
the wrong thing because it was comparing MVT's using
< rather than comparing the number of bits.  Removing
the < method makes this mistake impossible to commit.
Instead, add helper methods for comparing bits and use
them.

llvm-svn: 52098