reduction of address calculations down to basic pointer arithmetic.
This is currently off by default, as it needs a few other features
before it becomes generally useful. And even when enabled, full
strength reduction is only performed when it doesn't increase
register pressure, and when several other conditions are true.

This also factors out a bunch of exisiting LSR code out of
StrengthReduceStridedIVUsers into separate functions, and tidies
up IV insertion. This actually decreases register pressure even
in non-superhero mode. The change in iv-users-in-other-loops.ll
is an example of this; there are two more adds because there are
two fewer leas, and there is less spilling.

llvm-svn: 65108

since the latter just passes a null reference when
debugging is not enabled.

llvm-svn: 65060

llvm-svn: 65057

here.  Since we only do the transform if there is
one use, strip off any such users in the hope of
making the transform fire more often.

llvm-svn: 64926

trip count value when the original loop iteration condition is
signed and the canonical induction variable won't undergo signed
overflow. This isn't required for correctness; it just preserves
more information about original loop iteration values.

Add a getTruncateOrSignExtend method to ScalarEvolution,
following getTruncateOrZeroExtend.

llvm-svn: 64918

llvm-svn: 64917

llvm-svn: 64915

llvm-svn: 64888

are multiple IV's in a loop, some of them may under go signed
or unsigned wrapping even if the IV that's used in the loop
exit condition doesn't. Restrict sign-extension-elimination
and zero-extension-elimination to only those that operate on
the original loop-controlling IV.

llvm-svn: 64866

llvm-svn: 64859

crash because the alias would still be using the aliasee when the
aliasee was deleted.

llvm-svn: 64844

llvm-svn: 64811

modified in a way that may effect the trip count calculation. Change
IndVars to use this method when it rewrites pointer or floating-point
induction variables instead of using a doInitialization method to
sneak these changes in before ScalarEvolution has a chance to see
the loop. This eliminates the need for LoopPass to depend on
ScalarEvolution.

llvm-svn: 64810

eliminate all the extensions and all but the one required truncate
from the testcase, but the or/and/shift stuff still isn't zapped.

llvm-svn: 64809

llvm-svn: 64784

llvm-svn: 64773

llvm-svn: 64766

llvm-svn: 64703

llvm-svn: 64702

of an alloca or global variable.

llvm-svn: 64693

llvm-svn: 64626

been written for is no longer relevant with the elimination of
signed and unsigned types.

llvm-svn: 64625

Enhance instcombine to use the preferred field of
GetOrEnforceKnownAlignment in more cases, so that regular IR operations are
optimized in the same way that the intrinsics currently are.

llvm-svn: 64623

when I was looking at functions used by python.

Highlights include, better largefile support (64-bit file sizes on 32-bit
systems), fputs string is nocapture, popen/pclose added (popen being noalias
return), modf and frexp and friends. Also added some missing 'break' statements
and combined identical sections.

llvm-svn: 64615

one-definition-rule llvm-gcc changes (coming soon
to a tree near you!).

llvm-svn: 64588

alias can be morphed into the target.  Implement this
transform, and fix a crash in the existing transform at
the same time.

llvm-svn: 64583

Fix pr3571: If stride is a value defined by an instruction, make sure it dominates the loop preheader. When IV users are strength reduced, the stride is inserted into the preheader. It could create a use before def situation.

llvm-svn: 64579

llvm-svn: 64575

 - Test for signed and unsigned wrapping conditions, instead of just
   testing for non-negative induction ranges. 
 - Handle loops with GT comparisons, in addition to LT comparisons.
 - Support more cases of induction variables that don't start at 0.

llvm-svn: 64532

llvm-svn: 64531

No functionality change.

llvm-svn: 64530

printing getName(), so that unnamed values are printed correctly.

llvm-svn: 64468

about the code it describes, but at least now the comment
is right.

llvm-svn: 64465

llvm-svn: 64460

mark the first argument nocapture if endptr=NULL for each particular call.

llvm-svn: 64453

addrec in a different loop to check the value being added to
the accumulated Start value, not the Start value before it has
the new value added to it. This prevents LSR from going crazy
on the included testcase. Dale, please review.

llvm-svn: 64440

after sorting by stride value. This prevents it from missing
IV reuse opportunities in a host-sensitive manner.

llvm-svn: 64415

loop induction on LP64 targets. When the induction variable is
used in addressing, IndVars now is usually able to inserst a
64-bit induction variable and eliminates the sign-extending cast.
This is also useful for code using C "short" types for
induction variables on targets with 32-bit addressing.

Inserting a wider induction variable is easy; the tricky part is
determining when trunc(sext(i)) expressions are no-ops. This
requires range analysis of the loop trip count. A common case is
when the original loop iteration starts at 0 and exits when the
induction variable is signed-less-than a fixed value; this case
is now handled.

This replaces IndVarSimplify's OptimizeCanonicalIVType. It was
doing the same optimization, but it was limited to loops with
constant trip counts, because it was running after the loop
rewrite, and the information about the original induction
variable is lost by that point.

Rename ScalarEvolution's executesAtLeastOnce to
isLoopGuardedByCond, generalize it to be able to test for
ICMP_NE conditions, and move it to be a public function so that
IndVars can use it.

llvm-svn: 64407

when the loop has exactly one exit, and make use of it in
LoopIndexSplit.

llvm-svn: 64388

llvm-svn: 64376