Commit Graph

3227 Commits

Author SHA1 Message Date
Benjamin Kramer
4ac19470dc InstCombine: creating selects from -1 and 0 is fine, they combine into a sext from i1.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122453 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 23:12:15 +00:00
Duncan Sands
1cd05bb605 When determining whether the new instruction was already present in
the original instruction, half the cases were missed (making it not
wrong but suboptimal).  Also correct a typo (A <-> B) in the second
chunk. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122414 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 17:15:25 +00:00
Duncan Sands
b3898af89f Make this test not depend on how the variable is named.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122413 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 17:08:04 +00:00
Duncan Sands
37bf92b523 Add a generic expansion transform: A op (B op' C) -> (A op B) op' (A op C)
if both A op B and A op C simplify.  This fires fairly often but doesn't
make that much difference.  On gcc-as-one-file it removes two "and"s and
turns one branch into a select.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122399 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 13:36:08 +00:00
Owen Anderson
f056838956 Give GVN back the ability to perform simple conditional propagation on conditional branch values.
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
2010-12-21 23:54:34 +00:00
Duncan Sands
025c98bdbd Add an additional InstructionSimplify factorization test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122333 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 15:12:22 +00:00
Duncan Sands
07f30fbd73 While I don't think any later transforms can fire, it seems cleaner to
not assume this (for example in case more transforms get added below
it).  Suggested by Frits van Bommel.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122332 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 15:03:43 +00:00
Duncan Sands
9bd2c2e63c Fix typo in comment, spotted by Deewiant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122329 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 13:39:20 +00:00
Duncan Sands
3421d90853 Teach InstructionSimplify about distributive laws. These transforms fire
quite often, but don't make much difference in practice presumably because
instcombine also knows them and more.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122328 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 13:32:22 +00:00
Duncan Sands
566edb04b8 Add generic simplification of associative operations, generalizing
a couple of existing transforms.  This fires surprisingly often, for
example when compiling gcc "(X+(-1))+1->X" fires quite a lot as well
as various "and" simplifications (usually with a phi node operand).
Most of the time this doesn't make a real difference since the same
thing would have been done elsewhere anyway, eg: by instcombine, but
there are a few places where this results in simplifications that we
were not doing before.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122326 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 08:49:00 +00:00
Benjamin Kramer
5337f20c15 Teach InstCombine to merge (icmp ult (X + CA), C1) | (icmp eq X, C2) into (icmp ult (X + CA), C1 + 1) if C2 + CA == C1.
InstCombine creates these so now we compile x == 23 || x == 24 || x == 25 to
  %x.off = add i32 %x, -23
  %1 = icmp ult i32 %x.off, 3
instead of
  %x.off = add i32 %x, -23
  %1 = icmp ult i32 %x.off, 2
  %cmp3 = icmp eq i32 %x, 25
  %ret2 = or i1 %1, %cmp3


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122248 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 16:18:51 +00:00
Duncan Sands
ee9a2e322a Have SimplifyBinOp dispatch Xor, Add and Sub to the corresponding methods
(they had just been forgotten before).  Adding Xor causes "main" in the
existing testcase 2010-11-01-lshr-mask.ll to be hugely more simplified.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122245 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 14:47:04 +00:00
Chris Lattner
2b9375e44b fix PR8807 by making transformConstExprCastCall aware of byval arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122238 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 08:36:38 +00:00
Chris Lattner
0b66f63a26 when eliding a byval copy due to inlining a readonly function, we have
to make sure that the reused alloca has sufficient alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122236 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 08:10:40 +00:00
Chris Lattner
e7ae705c32 pull byval processing out to its own helper function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122235 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 07:57:41 +00:00
Chris Lattner
018fb767b9 fix PR8769, a miscompilation by inliner when inlining a function with a byval
argument.  The generated alloca has to have at least the alignment of the
byval, if not, the client may be making assumptions that the new alloca won't
satisfy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122234 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 07:45:28 +00:00
Chris Lattner
572335915f merge two tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122233 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 07:39:57 +00:00
Chris Lattner
b0af8ce1d9 filecheckize
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122232 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 07:38:24 +00:00
Mon P Wang
b085181258 Test case for r122215 when InstCombine optimizes memset
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122216 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-20 01:06:23 +00:00
Chris Lattner
a34b3cf953 X86 supports i8/i16 overflow ops (except i8 multiplies), we should
generate them.  

Now we compile:

define zeroext i8 @X(i8 signext %a, i8 signext %b) nounwind ssp {
entry:
  %0 = tail call %0 @llvm.sadd.with.overflow.i8(i8 %a, i8 %b)
  %cmp = extractvalue %0 %0, 1
  br i1 %cmp, label %if.then, label %if.end

into:

_X:                                     ## @X
## BB#0:                                ## %entry
	subl	$12, %esp
	movb	16(%esp), %al
	addb	20(%esp), %al
	jo	LBB0_2

Before we were generating:

_X:                                     ## @X
## BB#0:                                ## %entry
	pushl	%ebp
	movl	%esp, %ebp
	subl	$8, %esp
	movb	12(%ebp), %al
	testb	%al, %al
	setge	%cl
	movb	8(%ebp), %dl
	testb	%dl, %dl
	setge	%ah
	cmpb	%cl, %ah
	sete	%cl
	addb	%al, %dl
	testb	%dl, %dl
	setge	%al
	cmpb	%al, %ah
	setne	%al
	andb	%cl, %al
	testb	%al, %al
	jne	LBB0_2




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122186 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 20:03:11 +00:00
Chris Lattner
e5cbdca3bd recognize an unsigned add with overflow idiom into uadd.
This resolves a README entry and technically resolves PR4916,
but we still get poor code for the testcase in that PR because
GVN isn't CSE'ing uadd with add, filed as PR8817.

Previously we got:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	cmpq	%rdi, %rsi
	movl	$42, %eax
	cmovaq	%rsi, %rax
	ret

Now we get:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	movl	$42, %eax
	cmovbq	%rsi, %rax
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122182 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 19:37:52 +00:00
Chris Lattner
26b482d7a7 optimize uadd(x, cst) into a comparison when the normal
result is dead.  This is required for my next patch to not
regress the testsuite.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122181 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 19:35:32 +00:00
Chris Lattner
0a62474830 generalize the sadd creation code to not require that the
sadd formed is half the size of the original type. We can
now compile this into a sadd.i8:

unsigned char X(char a, char b) {
  int res = a+b;
  if ((unsigned )(res+128) > 255U)
    abort();
  return res;
}




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122178 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 18:35:09 +00:00
Chris Lattner
dd7e837374 fix another miscompile in the llvm.sadd formation logic: it wasn't
checking to see if the high bits of the original add result were dead.
Inserting a smaller add and zexting back to that size is not good enough.

This is likely to be the fix for 8816.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122177 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 18:22:06 +00:00
Chris Lattner
368397bb7d fix a bug (possibly 8816) in the sadd forming xform: it isn't
profitable (or safe) to promote code when the add-with-constant
has other uses.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122175 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 17:59:02 +00:00
Chris Lattner
1dec0d2704 Enhance LICM to promote alias sets whose pointers themselves are stored,
which doesn't affect the memory address being promoted.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122172 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 05:57:25 +00:00
Chris Lattner
1c0af0ed25 fix PR8602, a bug in an assertion: a volatile store *of* a pointer
does not make the alias set for that pointer volatile, just stores
*to* the pointer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122171 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 05:51:54 +00:00
Chris Lattner
a0d172f7fe revert r122164, I'm going to go with a different approach.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122168 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 04:23:03 +00:00
Chris Lattner
140f4a315b first step to fixing PR8642: don't fold away empty basic blocks
which have trapping constant exprs in them due to PHI nodes.
Eliminating them can cause the constant expr to be evalutated
on new paths if the input edges are critical.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122164 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 03:02:34 +00:00
Chris Lattner
78d0094e4c move this test into the ARM test so that it is only run when the arm backend
is enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122163 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 02:58:14 +00:00
Nate Begeman
9a3dc55202 Add vector versions of some existing scalar transforms to aid codegen in matching psign & pblend operations to the IR produced by clang/gcc for their C idioms.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122105 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 23:12:19 +00:00
Owen Anderson
e63dda51c2 Reapply r121905 (automatic synthesis of @llvm.sadd.with.overflow) with a fix for a bug that manifested itself
on the DragonEgg self-host bot.  Unfortunately, the testcase is pretty messy and doesn't reduce well due to
interactions with other parts of InstCombine.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122072 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 18:08:00 +00:00
Benjamin Kramer
14c0987bd9 SimplifyCFG: Ranges can be larger than 64 bits. Fixes Release-selfhost build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122054 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 10:48:14 +00:00
Chris Lattner
e27db74a60 improve switch formation to handle small range
comparisons formed by comparisons.  For example,
this:

void foo(unsigned x) {
  if (x == 0 || x == 1 || x == 3 || x == 4 || x == 6) 
    bar();
}

compiles into:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	cmpl	$6, %edi
	ja	LBB0_2
## BB#1:                                ## %entry
	movl	%edi, %eax
	movl	$91, %ecx
	btq	%rax, %rcx
	jb	LBB0_3

instead of:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	cmpl	$2, %edi
	jb	LBB0_4
## BB#1:                                ## %switch.early.test
	cmpl	$6, %edi
	ja	LBB0_3
## BB#2:                                ## %switch.early.test
	movl	%edi, %eax
	movl	$88, %ecx
	btq	%rax, %rcx
	jb	LBB0_4

This catches a bunch of cases in GCC, which look like this:

 %804 = load i32* @which_alternative, align 4, !tbaa !0
 %805 = icmp ult i32 %804, 2
 %806 = icmp eq i32 %804, 3
 %or.cond121 = or i1 %805, %806
 %807 = icmp eq i32 %804, 4
 %or.cond124 = or i1 %or.cond121, %807
 br i1 %or.cond124, label %.thread, label %808

turning this into a range comparison.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122045 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 06:20:15 +00:00
Dan Gohman
c32046e6ea Revert r64460. strtol and friends cannot be marked readonly, even with
a null endptr argument, because they may write to errno.

This fixes a seflhost miscompile observed on Linux targets when TBAA
was enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122014 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 01:09:43 +00:00
Duncan Sands
ebef48ea4b Speculatively revert commit 121905 since it looks like it might have broken the
dragonegg self-host buildbot.  Original commit message:

Add an InstCombine transform to recognize instances of manual overflow-safe addition
(performing the addition in a wider type and explicitly checking for overflow), and
fold them down to intrinsics.  This currently only supports signed-addition, but could
be generalized if someone works out the magic constant formulas for other operations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121965 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-16 09:40:54 +00:00
Dan Gohman
f4177aa019 Preserve TBAA tags when doing load PRE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121921 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 23:53:55 +00:00
Owen Anderson
12984de314 Add an InstCombine transform to recognize instances of manual overflow-safe addition
(performing the addition in a wider type and explicitly checking for overflow), and
fold them down to intrinsics.  This currently only supports signed-addition, but could
be generalized if someone works out the magic constant formulas for other operations.

Fixes <rdar://problem/8558713>.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121905 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 22:32:38 +00:00
Frits van Bommel
26e097ca4b Teach jump threading to "look through" a select when the branch direction of a terminator depends on it.
When it sees a promising select it now tries to figure out whether the condition of the select is known in any of the predecessors and if so it maps the operands appropriately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121859 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 09:51:20 +00:00
Owen Anderson
86e8a700f5 Fix PR8790, another instance where unreachable code can cause instruction simplification to fail,
this case involve a select that simplifies to itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121817 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 00:55:35 +00:00
Chris Lattner
3aff13b82a - Insert new instructions before DomBlock's terminator,
which is simpler than finding a place to insert in BB.
 - Don't perform the 'if condition hoisting' xform on certain
   i1 PHIs, as it interferes with switch formation.

This re-fixes "example 7", without breaking the world hopefully.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121764 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14 08:46:09 +00:00
Chris Lattner
60d410d7bb fix two significant issues with FoldTwoEntryPHINode:
first, it can kick in on blocks whose conditions have been
folded to a constant, even though one of the edges will be
trivially folded.

second, it doesn't clean up the "if diamond" that it just 
eliminated away.  This is a problem because other simplifycfg
xforms kick in depending on the order of block visitation,
causing pointless work.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121762 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14 08:01:53 +00:00
Chris Lattner
8168efffa7 fix yet anohter broken line
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121750 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14 06:09:07 +00:00
Chris Lattner
117f8cffc5 reapply my recent change that disables a piece of the switch formation
work, but fixes 400.perlbmk.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121749 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14 05:57:30 +00:00
Owen Anderson
2d9220e8f5 Fix recent buildbot breakage by pulling SimplifyCFG back to its state as of r121694, the most recent state
where I'm confident there were no crashes or miscompilations.  XFAIL the test added since then for now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121733 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 23:49:28 +00:00
Chris Lattner
f9a1b2a4cf temporarily disable part of my previous patch, which causes an iterator invalidation issue, causing a crash on some versions of perlbmk.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121728 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 23:02:19 +00:00
Benjamin Kramer
cf8b3257c0 Fix sort predicate. qsort(3)'s predicate semantics differ from std::sort's. Fixes PR 8780.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121705 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 18:20:38 +00:00
Chris Lattner
a9f6bbea62 reinstate my patch: the miscompile was caused by an inverted branch in the
'and' case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121695 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 08:12:19 +00:00
Chris Lattner
92407e5895 Completely disable the optimization I added in r121680 until
I can track down a miscompile.  This should bring the buildbots
back to life


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121693 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 07:41:29 +00:00
Chris Lattner
daa02ab70c Make simplifycfg reprocess newly formed "br (cond1 | cond2)" conditions
when simplifying, allowing them to be eagerly turned into switches.  This
is the last step required to get "Example 7" from this blog post:
http://blog.regehr.org/archives/320

On X86, we now generate this machine code, which (to my eye) seems better
than the ICC generated code:

_crud:                                  ## @crud
## BB#0:                                ## %entry
	cmpb	$33, %dil
	jb	LBB0_4
## BB#1:                                ## %switch.early.test
	addb	$-34, %dil
	cmpb	$58, %dil
	ja	LBB0_3
## BB#2:                                ## %switch.early.test
	movzbl	%dil, %eax
	movabsq	$288230376537592865, %rcx ## imm = 0x400000017001421
	btq	%rax, %rcx
	jb	LBB0_4
LBB0_3:                                 ## %lor.rhs
	xorl	%eax, %eax
	ret
LBB0_4:                                 ## %lor.end
	movl	$1, %eax
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121690 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 07:00:06 +00:00