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

don't make i1 phis when it won't be possible to eliminate them.

llvm-svn: 52097

Speculatively execute a block when the the block is the then part of a triangle shape and it contains a single, side effect free, cheap instruction. The branch is eliminated by adding a select instruction. i.e.

Turn                                                                                                                                                                                                       
BB:                                                                                                                                                                                                        
    %t1 = icmp                                                                                                                                                                                             
    br i1 %t1, label %BB1, label %BB2                                                                                                                                                                      
BB1:                                                                                                                                                                                                       
    %t3 = add %t2, c                                                                                                                                                                                       
    br label BB2                                                                                                                                                                                           
BB2:                                                                                                                                                                                                       
=>                                                                                                                                                                                                         
BB:                                                                                                                                                                                                        
    %t1 = icmp                                                                                                                                                                                             
    %t4 = add %t2, c                                                                                                                                                                                       
    %t3 = select i1 %t1, %t2, %t3

llvm-svn: 52073

llvm-svn: 52053

and better control the abstraction.  Rename the type
to MVT.  To update out-of-tree patches, the main
thing to do is to rename MVT::ValueType to MVT, and
rewrite expressions like MVT::getSizeInBits(VT) in
the form VT.getSizeInBits().  Use VT.getSimpleVT()
to extract a MVT::SimpleValueType for use in switch
statements (you will get an assert failure if VT is
an extended value type - these shouldn't exist after
type legalization).
This results in a small speedup of codegen and no
new testsuite failures (x86-64 linux).

llvm-svn: 52044

otherwise, opt might crash.

llvm-svn: 52041

crash the opt. Just fix this.

Test case in llvm/test/Transforms/InstCombine/2008-06-05-ashr-crash.ll

llvm-svn: 52003

work and how to replace them into individual values. Also, when trying to
replace an aggregrate that is used by load or store with a single (large)
integer, don't crash (but don't replace the aggregrate either).

Also adds a testcase for both structs and arrays.

llvm-svn: 51997

not other instructions. This fixes a crash with the added testcase.

llvm-svn: 51992