Change various bits of code to make better use of the existing PHINode
API, to insulate them from forthcoming changes in how PHINodes store
their operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133434 91177308-0d34-0410-b5e6-96231b3b80d8
causing it to get into infinite loops when it would widen a
load (which can necessarily leave around dead loads).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131847 91177308-0d34-0410-b5e6-96231b3b80d8
a nice and tidy:
%x1 = load i32* %0, align 4
%1 = icmp eq i32 %x1, 1179403647
br i1 %1, label %if.then, label %if.end
instead of doing lots of loads and branches. May the FreeBSD bootloader
long fit in its allocated space.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130416 91177308-0d34-0410-b5e6-96231b3b80d8
wider load would allow elimination of subsequent loads, and when the wider
load is still a native integer type. This eliminates a ton of loads on
various benchmarks involving struct fields, though it is somewhat hobbled
by clang not being very aggressive about field alignment.
This is yet another step along the way towards resolving PR6627.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130390 91177308-0d34-0410-b5e6-96231b3b80d8
translation fails. We were bailing out in some cases that would
cause us to miss GVN'ing some non-local cases away.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130206 91177308-0d34-0410-b5e6-96231b3b80d8
return it as a clobber. This allows GVN to do smart things.
Enhance GVN to be smart about the case when a small load is clobbered
by a larger overlapping load. In this case, forward the value. This
allows us to compile stuff like this:
int test(void *P) {
int tmp = *(unsigned int*)P;
return tmp+*((unsigned char*)P+1);
}
into:
_test: ## @test
movl (%rdi), %ecx
movzbl %ch, %eax
addl %ecx, %eax
ret
which has one load. We already handled the case where the smaller
load was from a must-aliased base pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130180 91177308-0d34-0410-b5e6-96231b3b80d8
with BasicAA's DecomposeGEPExpression, which recently began
using a TargetData. This fixes PR8968, though the testcase
is awkward to reduce.
Also, update several off GetUnderlyingObject's users
which happen to have a TargetData handy to pass it in.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124134 91177308-0d34-0410-b5e6-96231b3b80d8
phi nodes. It is called from MergeBlockIntoPredecessor which is
called from GVN, which claims to preserve these.
I'm skeptical that this is the actual problem behind PR8954, but
this is a stab in the right direction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123222 91177308-0d34-0410-b5e6-96231b3b80d8
fewer things into the value numbering maps, but any speedup is beneath the noise threshold on my machine
on 403.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122844 91177308-0d34-0410-b5e6-96231b3b80d8
avoids adding them to the various value numbering tables, resulting in a minor (~3%) speedup for GVN
on 40.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122819 91177308-0d34-0410-b5e6-96231b3b80d8
I still think that LVI should be handling this, but that capability is some ways off in the future,
and this matters for some significant benchmarks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122378 91177308-0d34-0410-b5e6-96231b3b80d8
this was a tree of hashtables, and a query recursed into the table for the immediate dominator ad infinitum
if the initial lookup failed. This led to really bad performance on tall, narrow CFGs.
We can instead replace it with what is conceptually a multimap of value numbers to leaders (actually
represented by a hashtable with a list of Value*'s as the value type), and then
determine which leader from that set to use very cheaply thanks to the DFS numberings maintained by
DominatorTree. Because there are typically few duplicates of a given value, this scan tends to be
quite fast. Additionally, we use a custom linked list and BumpPtr allocation to avoid any unnecessary
allocation in representing the value-side of the multimap.
This change brings with it a 15% (!) improvement in the total running time of GVN on 403.gcc, which I
think is pretty good considering that includes all the "real work" being done by MemDep as well.
The one downside to this approach is that we can no longer use GVN to perform simple conditional progation,
but that seems like an acceptable loss since we now have LVI and CorrelatedValuePropagation to pick up
the slack. If you see conditional propagation that's not happening, please file bugs against LVI or CVP.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119714 91177308-0d34-0410-b5e6-96231b3b80d8
systematically, CollapsePhi will always return null here. Note
that CollapsePhi did an extra check, isSafeReplacement, which
the SimplifyInstruction logic does not do. I think that check
was bogus - I guess we will soon find out! (It was originally
added in commit 41998 without a testcase).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119456 91177308-0d34-0410-b5e6-96231b3b80d8
"%z = %x and %y". If GVN can prove that %y equals %x, then it turns
this into "%z = %x and %x". With the new code, %z will be replaced
with %x everywhere (and then deleted). Previously %z would be value
numbered too, which is a waste of time. Also, while a clever value
numbering algorithm would give %z the same value number as %x, our
current one doesn't do so (at least I don't think it does). The new
logic has an essentially equivalent effect to what you would get if
%z was given the same value number as %x, i.e. it should make value
numbering smarter. While there, get hold of target data once at the
start rather than a gazillion times all over the place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118923 91177308-0d34-0410-b5e6-96231b3b80d8
references. For example, this allows gvn to eliminate the load in
this example:
void foo(int n, int* p, int *q) {
p[0] = 0;
p[1] = 1;
if (n) {
*q = p[0];
}
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118714 91177308-0d34-0410-b5e6-96231b3b80d8
must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize
the pass's dependencies.
Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.
I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems
with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass
registration/creation, please send the testcase to me directly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
perform initialization without static constructors AND without explicit initialization
by the client. For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve. I hope to be able to relax
the latter requirement in the future.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8
Anyone interested in more general PRE would be better served by implementing it separately, to get real
anticipation calculation, etc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115337 91177308-0d34-0410-b5e6-96231b3b80d8
code size (making this transform code size neutral), and it allows us to hoist values out of loops, which is always
a good thing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115205 91177308-0d34-0410-b5e6-96231b3b80d8
Splitting critical edges at the merge point only addressed part of the issue; it is also possible for non-post-domination
to occur when the path from the load to the merge has branches in it. Unfortunately, full anticipation analysis is
time-consuming, so for now approximate it. This is strictly more conservative than real anticipation, so we will miss
some cases that real PRE would allow, but we also no longer insert loads into paths where they didn't exist before. :-)
This is a very slight net positive on SPEC for me (0.5% on average). Most of the benchmarks are largely unaffected, but
when it pays off it pays off decently: 181.mcf improves by 4.5% on my machine.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114785 91177308-0d34-0410-b5e6-96231b3b80d8
I'm sure it is harmless. Original commit message:
If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112810 91177308-0d34-0410-b5e6-96231b3b80d8
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112699 91177308-0d34-0410-b5e6-96231b3b80d8
indirect branches in all the predecessors. This avoids unnecessarily
splitting edges in cases where load PRE is not possible anyway.
Thanks to Jakub Staszak for pointing this out.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103034 91177308-0d34-0410-b5e6-96231b3b80d8
Probably the best way to know that all getOperand() calls have been handled
is to replace that API instead of updating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101579 91177308-0d34-0410-b5e6-96231b3b80d8
with a fix for self-hosting
rotate CallInst operands, i.e. move callee to the back
of the operand array
the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101465 91177308-0d34-0410-b5e6-96231b3b80d8
with a fix
rotate CallInst operands, i.e. move callee to the back
of the operand array
the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101397 91177308-0d34-0410-b5e6-96231b3b80d8
of the operand array
the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101364 91177308-0d34-0410-b5e6-96231b3b80d8
predecessors before returning. Otherwise, if multiple predecessor edges need
splitting, we only get one of them per iteration. This makes a small but
measurable compile time improvement with -enable-full-load-pre.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97521 91177308-0d34-0410-b5e6-96231b3b80d8
argument is non-null, pass it along to PHITranslateSubExpr so that it can
prefer using existing values that dominate the PredBB, instead of just
blindly picking the first equivalent value that it finds on a uselist.
Also when the DominatorTree is specified, have PHITranslateValue filter
out any result that does not dominate the PredBB. This is basically just
refactoring the check that used to be in GetAvailablePHITranslatedSubExpr
and also in GVN.
Despite my initial expectations, this change does not affect the results
of GVN for any testcases that I could find, but it should help compile time.
Before this change, if PHITranslateSubExpr picked a value that does not
dominate, PHITranslateWithInsertion would then insert a new value, which GVN
would later determine to be redundant and would replace. By picking a good
value to begin with, we save GVN the extra work of inserting and then
replacing a new value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97010 91177308-0d34-0410-b5e6-96231b3b80d8
