Commit Graph

252 Commits

Author SHA1 Message Date
Chris Lattner 9b7d99eb76 The phi translated pointer can be computed when returning a partially cached result
instead of stored.  This reduces memdep memory usage, and also eliminates a bunch of
weakvh's.  This speeds up gvn on gcc.c-torture/20001226-1.c from 23.9s to 8.45s (2.8x)
on a different machine than earlier.

llvm-svn: 91885
2009-12-22 04:25:02 +00:00
Chris Lattner bf20018423 Add a fastpath to Load GVN to special case when we have exactly one dominating
load to avoid even messing around with SSAUpdate at all.  In this case (which
is very common, we can just use the input value directly).

This speeds up GVN time on gcc.c-torture/20001226-1.c from 36.4s to 16.3s,
which still isn't great, but substantially better and this is a simple speedup
that applies to lots of different cases.

llvm-svn: 91851
2009-12-21 23:15:48 +00:00
Chris Lattner 927b0ac4b2 refactor some code out to a new helper method.
llvm-svn: 91849
2009-12-21 23:04:33 +00:00
Dan Gohman 57e808628c Eliminte unnecessary uses of <cstdio>.
llvm-svn: 91666
2009-12-18 03:25:51 +00:00
Chris Lattner 45d040bd85 Remove isPod() from DenseMapInfo, splitting it out to its own
isPodLike type trait.  This is a generally useful type trait for
more than just DenseMap, and we really care about whether something
acts like a pod, not whether it really is a pod.

llvm-svn: 91421
2009-12-15 07:26:43 +00:00
Chris Lattner 9ccc879006 Fix PR5744, a case where we were getting the pointer size instead of the
value size.  This only manifested when memdep inprecisely returns clobber,
which is do to a caching issue in the PR5744 testcase.  We can 'efficiently
emulate' this by using '-no-aa'

llvm-svn: 91004
2009-12-10 00:11:45 +00:00
Chris Lattner 3ddf804f78 allow this to build when the #if 0's are enabled. No functionality change.
llvm-svn: 90999
2009-12-10 00:04:46 +00:00
Chris Lattner ca5f9cb18b fix hte last remaining known (by me) phi translation bug. When we reanalyze
clobbers to forward pieces of large stores to small loads, we need to consider
the properly phi translated pointer in the store block.

llvm-svn: 90978
2009-12-09 18:21:46 +00:00
Chris Lattner f8ba1253f1 change GetStoreValueForLoad to use IRBuilder, which is cleaner and
implicitly constant folds.

llvm-svn: 90977
2009-12-09 18:13:28 +00:00
Chris Lattner 07df9efb35 change AnalyzeLoadFromClobberingMemInst/AnalyzeLoadFromClobberingStore
to require the load ty/ptr to be passed in, no functionality change.

llvm-svn: 90960
2009-12-09 07:37:07 +00:00
Chris Lattner 0def861ee9 change AnalyzeLoadFromClobberingWrite and clients to pass in type
and pointer instead of the load.  No functionality change.

llvm-svn: 90959
2009-12-09 07:34:10 +00:00
Chris Lattner 0c31547168 change NonLocalDepEntry from being a typedef for an std::pair to be its
own small class.  No functionality change.

llvm-svn: 90956
2009-12-09 07:08:01 +00:00
Chris Lattner 946b58dd90 add some aborts to #if 0's.
llvm-svn: 90929
2009-12-09 02:41:54 +00:00
Chris Lattner 972e6d8d00 Switch GVN and memdep to use PHITransAddr, which correctly handles
phi translation of complex expressions like &A[i+1].  This has the
following benefits:

1. The phi translation logic is all contained in its own class with
   a strong interface and verification that it is self consistent.

2. The logic is more correct than before.  Previously, if intermediate
   expressions got PHI translated, we'd miss the update and scan for
   the wrong pointers in predecessor blocks.  @phi_trans2 is a testcase
   for this.

3. We have a lot less code in memdep.

We can handle phi translation across blocks of things like @phi_trans3,
which is pretty insane :).

This patch should fix the miscompiles of 255.vortex, and I tested it 
with a bootstrap of llvm-gcc, llvm-test and dejagnu of course.

llvm-svn: 90926
2009-12-09 01:59:31 +00:00
Chris Lattner 778cb92235 constant fold loads from memcpy's from global constants. This is important
because clang lowers nontrivial automatic struct/array inits to memcpy from
a global array.

llvm-svn: 90698
2009-12-06 05:29:56 +00:00
Chris Lattner 93236ba327 add support for forwarding mem intrinsic values to non-local loads.
llvm-svn: 90697
2009-12-06 04:54:31 +00:00
Chris Lattner 42376066eb Handle forwarding local memsets to loads. For example, we optimize this:
short x(short *A) {
  memset(A, 1, sizeof(*A)*100);
  return A[42];
}

to 'return 257' instead of doing the load.  

llvm-svn: 90695
2009-12-06 01:57:02 +00:00
Owen Anderson 0b6e260066 Fix this crasher, and add a FIXME for a missed optimization.
llvm-svn: 90408
2009-12-03 03:43:29 +00:00
Owen Anderson b9878ee6b6 Cleanup/remove some parts of the lifetime region handling code in memdep and GVN,
per Chris' comments.  Adjust testcases to match.

llvm-svn: 90304
2009-12-02 07:35:19 +00:00
Chris Lattner c468025ac9 factor some code better.
llvm-svn: 90299
2009-12-02 06:44:58 +00:00
Chris Lattner 32140312ca reenable load address insertion in load pre. This allows us to
handle cases like this:
void test(int N, double* G) {
  long j;
  for (j = 1; j < N - 1; j++)
      G[j+1] = G[j] + G[j+1];
}

where G[1] isn't live into the loop.

llvm-svn: 90041
2009-11-28 16:08:18 +00:00
Chris Lattner 44da5bd837 Enhance InsertPHITranslatedPointer to be able to return a list of newly
inserted instructions.  No functionality change until someone starts using it.

llvm-svn: 90039
2009-11-28 15:39:14 +00:00
Chris Lattner cf0b198827 disable value insertion for now, I need to figure out how
to inform GVN about the newly inserted values.  This fixes 
PR5631.

llvm-svn: 90022
2009-11-27 22:50:07 +00:00
Chris Lattner 2be52e72ae Rework InsertPHITranslatedPointer to handle the recursive case, this
fixes PR5630 and sets the stage for the next phase of goodness (testcase
pending).

llvm-svn: 90019
2009-11-27 22:05:15 +00:00
Chris Lattner 25be93dfed teach GVN's load PRE to insert computations of the address in predecessors
where it is not available.  It's unclear how to get this inserted 
computation into GVN's scalar availability sets, Owen, help? :)

llvm-svn: 89997
2009-11-27 08:25:10 +00:00
Chris Lattner a9a76ccf56 Fix phi translation in load PRE to agree with the phi
translation done by memdep, and reenable gep translation 
again.

llvm-svn: 89992
2009-11-27 06:31:14 +00:00
Dan Gohman 81132465d3 Add an option for running GVN with redundant load processing disabled.
llvm-svn: 88742
2009-11-14 02:27:51 +00:00
Jeffrey Yasskin b40d3f76a0 Fix DenseMap iterator constness.
This patch forbids implicit conversion of DenseMap::const_iterator to
DenseMap::iterator which was possible because DenseMapIterator inherited
(publicly) from DenseMapConstIterator. Conversion the other way around is now
allowed as one may expect.

The template DenseMapConstIterator is removed and the template parameter
IsConst which specifies whether the iterator is constant is added to
DenseMapIterator.

Actually IsConst parameter is not necessary since the constness can be
determined from KeyT but this is not relevant to the fix and can be addressed
later.

Patch by Victor Zverovich!

llvm-svn: 86636
2009-11-10 01:02:17 +00:00
Chris Lattner a546dcf418 Make sure PRE doesn't split crit edges from indirectbr.
llvm-svn: 85692
2009-10-31 22:11:15 +00:00
Evan Cheng 5a6b9c40d6 Add option to createGVNPass to disable PRE.
llvm-svn: 85609
2009-10-30 20:12:24 +00:00
Owen Anderson 2b2bd28973 Treat lifetime begin/end markers as allocations/frees respectively for the
purposes for GVN/DSE.

llvm-svn: 85383
2009-10-28 07:05:35 +00:00
Victor Hernandez f390e04a47 Rename MallocFreeHelper as MemoryBuiltins
llvm-svn: 85286
2009-10-27 20:05:49 +00:00
Victor Hernandez 762195bd01 Rename MallocHelper as MallocFreeHelper, since it now also identifies calls to free()
llvm-svn: 85181
2009-10-26 23:58:56 +00:00
Victor Hernandez 8acf2956b8 Remove AllocationInst. Since MallocInst went away, AllocaInst is the only subclass of AllocationInst, so it no longer is necessary.
llvm-svn: 84969
2009-10-23 21:09:37 +00:00
Chris Lattner 8ed7bef409 make GVN work better when TD is not around:
"In the existing code, if the load and the value to replace it with are
of different types *and* target data is available, it tries to use the
target data to coerce the replacement value to the type of the load.
Otherwise, it skips all effort to handle the type mismatch and just
feeds the wrongly-typed replacement value to replaceAllUsesWith, which
triggers an assertion.

The patch replaces it with an outer if checking for type mismatch, and
an inner if-else that checks whether target data is available and, if
not, returns false rather than trying to replace the load."

Patch by Kenneth Uildriks!

llvm-svn: 84739
2009-10-21 04:11:19 +00:00
Owen Anderson 168ad6985e Refactor lookup_or_add to contain _MUCH_ less duplicated code. Add support for
numbering first class aggregate instructions while we're at it.

llvm-svn: 84547
2009-10-19 22:14:22 +00:00
Owen Anderson 1059b5b32d Simplify some code.
llvm-svn: 84533
2009-10-19 21:14:57 +00:00
Devang Patel 92f8619923 Use isVoidTy()
llvm-svn: 84118
2009-10-14 17:29:00 +00:00
Chris Lattner b6c65faa64 switch GVN to use SSAUpdater. Besides removing a lot of complexity
from GVN, this also speeds it up, inserts fewer PHI nodes (see the
testcase) and allows it to remove more loads (due to fewer PHI nodes
standing in the way).

llvm-svn: 83746
2009-10-10 23:50:30 +00:00
Chris Lattner 89d2a5c4f3 remove dead code
llvm-svn: 83742
2009-10-10 23:04:12 +00:00
Chris Lattner f30a2b0c86 random tidying
llvm-svn: 83701
2009-10-10 06:22:45 +00:00
Chris Lattner 4425660b1f simplify some code.
llvm-svn: 82936
2009-09-27 21:46:50 +00:00
Nick Lewycky 42fb7452df Instruction::clone does not need to take an LLVMContext&. Remove that and
update all the callers.

llvm-svn: 82889
2009-09-27 07:38:41 +00:00
Chris Lattner 247053867e big endian systems shift by bits too, hopefully this will fix the ppc
bootstrap problems.

llvm-svn: 82464
2009-09-21 17:55:47 +00:00
Chris Lattner 9045f235d2 fix PR5016, a crash I introduced in GVN handing first class
arrays and structs, which cannot be bitcast to integers.

llvm-svn: 82460
2009-09-21 17:24:04 +00:00
Chris Lattner 4d8af2f1ae enable non-local analysis and PRE of large store -> little load.
This doesn't kick in too much because of phi translation issues,
but this can be resolved in the future.

llvm-svn: 82447
2009-09-21 06:48:08 +00:00
Chris Lattner 0cdc17eb50 convert an std::pair to an explicit struct.
llvm-svn: 82446
2009-09-21 06:30:24 +00:00
Chris Lattner d28f90897a move some functions, add a comment.
llvm-svn: 82444
2009-09-21 06:24:16 +00:00
Chris Lattner 9d7fb29522 split HandleLoadFromClobberingStore in two pieces: one that does the
analysis, one that does the xform.

llvm-svn: 82443
2009-09-21 06:22:46 +00:00
Chris Lattner 0a9616d906 Improve GVN to be able to forward substitute a small load
from a piece of a large store when both are in the same block.

This allows clang to compile the testcase in PR4216 to this code:

_test_bitfield:
	movl	4(%esp), %eax
	movl	%eax, %ecx
	andl	$-65536, %ecx
	orl	$32962, %eax
	andl	$40186, %eax
	orl	%ecx, %eax
	ret

This is not ideal, but is a whole lot better than the code produced
by llvm-gcc:

_test_bitfield:
	movw	$-32574, %ax
	orw	4(%esp), %ax
	andw	$-25350, %ax
	movw	%ax, 4(%esp)
	movw	7(%esp), %cx
	shlw	$8, %cx
	movzbl	6(%esp), %edx
	orw	%cx, %dx
	movzwl	%dx, %ecx
	shll	$16, %ecx
	movzwl	%ax, %eax
	orl	%ecx, %eax
	ret

and dramatically better than that produced by gcc 4.2:

_test_bitfield:
	pushl	%ebx
	call	L3
"L00000000001$pb":
L3:
	popl	%ebx
	movl	8(%esp), %eax
	leal	0(,%eax,4), %edx
	sarb	$7, %dl
	movl	%eax, %ecx
	andl	$7168, %ecx
	andl	$-7201, %ebx
	movzbl	%dl, %edx
	andl	$1, %edx
	sall	$5, %edx
	orl	%ecx, %ebx
	orl	%edx, %ebx
	andl	$24, %eax
	andl	$-58336, %ebx
	orl	%eax, %ebx
	orl	$32962, %ebx
	movl	%ebx, %eax
	popl	%ebx
	ret

llvm-svn: 82439
2009-09-21 05:57:11 +00:00