Benjamin Kramer
33828bcb24
SimplifyCFG: Track the number of used icmps when turning a icmp chain into a switch. If we used only one icmp, don't turn it into a switch.
...
Also prevent the switch-to-icmp transform from creating identity adds, noticed by Marius Wachtler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125056 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-07 22:37:28 +00:00
Benjamin Kramer
042b27f40e
SimplifyCFG: Also transform switches that represent a range comparison but are not sorted into sub+icmp.
...
This transforms another 1000 switches in gcc.c.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124826 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 22:51:41 +00:00
Benjamin Kramer
56442dfdcf
SimplifyCFG: Turn switches into sub+icmp+branch if possible.
...
This makes the job of the later optzn passes easier, allowing the vast amount of
icmp transforms to chew on it.
We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting
binary on i386-linux.
The testcase from README.txt now compiles into
decl %edi
cmpl $3, %edi
sbbl %eax, %eax
andl $1, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124724 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-02 15:56:22 +00:00
Evan Cheng
c3f507f98a
Re-apply r124518 with fix. Watch out for invalidated iterator.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124526 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29 04:46:23 +00:00
Evan Cheng
b0a42fdb36
Revert r124518. It broke Linux self-host.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124522 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29 02:43:04 +00:00
Evan Cheng
5e6940788f
Re-commit r124462 with fixes. Tail recursion elim will now dup ret into unconditional predecessor to enable TCE on demand.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124518 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29 01:29:26 +00:00
Evan Cheng
1b5c0cb71d
Revert r124462. There are a few big regressions that I need to fix first.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124478 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 07:12:38 +00:00
Evan Cheng
40f64cb0de
- Stop simplifycfg from duplicating "ret" instructions into unconditional
...
branches. PR8575, rdar://5134905, rdar://8911460.
- Allow codegen tail duplication to dup small return blocks after register
allocation is done.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124462 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 02:19:21 +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
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
Chris Lattner
97bd89ece3
fix a bug in r121680 that upset the various buildbots.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 05:34:18 +00:00
Chris Lattner
c232a2e559
make these tests a bit less fragile
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121682 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 05:10:30 +00:00
Chris Lattner
7312a22ed6
enhance the "change or icmp's into switch" xform to handle one value in an
...
'or sequence' that it doesn't understand. This allows us to optimize
something insane like this:
int crud (unsigned char c, unsigned x)
{
if(((((((((( (int) c <= 32 ||
(int) c == 46) || (int) c == 44)
|| (int) c == 58) || (int) c == 59) || (int) c == 60)
|| (int) c == 62) || (int) c == 34) || (int) c == 92)
|| (int) c == 39) != 0)
foo();
}
into:
define i32 @crud(i8 zeroext %c, i32 %x) nounwind ssp noredzone {
entry:
%cmp = icmp ult i8 %c, 33
br i1 %cmp, label %if.then, label %switch.early.test
switch.early.test: ; preds = %entry
switch i8 %c, label %if.end [
i8 39, label %if.then
i8 44, label %if.then
i8 58, label %if.then
i8 59, label %if.then
i8 60, label %if.then
i8 62, label %if.then
i8 46, label %if.then
i8 92, label %if.then
i8 34, label %if.then
]
by pulling the < comparison out ahead of the newly formed switch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121680 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 04:50:38 +00:00
Chris Lattner
f5198e7fe3
merge two tests
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121679 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 04:45:56 +00:00
Chris Lattner
abf706703f
Fix my previous patch to handle a degenerate case that the llvm-gcc
...
bootstrap buildbot tripped over.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121674 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 03:43:57 +00:00
Chris Lattner
61c77449c7
fix a fairly serious oversight with switch formation from
...
or'd conditions. Previously we'd compile something like this:
int crud (unsigned char c) {
return c == 62 || c == 34 || c == 92;
}
into:
switch i8 %c, label %lor.rhs [
i8 62, label %lor.end
i8 34, label %lor.end
]
lor.rhs: ; preds = %entry
%cmp8 = icmp eq i8 %c, 92
br label %lor.end
lor.end: ; preds = %entry, %entry, %lor.rhs
%0 = phi i1 [ true, %entry ], [ %cmp8, %lor.rhs ], [ true, %entry ]
%lor.ext = zext i1 %0 to i32
ret i32 %lor.ext
which failed to merge the compare-with-92 into the switch. With this patch
we simplify this all the way to:
switch i8 %c, label %lor.rhs [
i8 62, label %lor.end
i8 34, label %lor.end
i8 92, label %lor.end
]
lor.rhs: ; preds = %entry
br label %lor.end
lor.end: ; preds = %entry, %entry, %entry, %lor.rhs
%0 = phi i1 [ true, %entry ], [ false, %lor.rhs ], [ true, %entry ], [ true, %entry ]
%lor.ext = zext i1 %0 to i32
ret i32 %lor.ext
which is much better for codegen's switch lowering stuff. This kicks in 33 times
on 176.gcc (for example) cutting 103 instructions off the generated code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121671 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 03:18:54 +00:00
Frits van Bommel
7ac40c3ffa
Teach SimplifyCFG to turn
...
(indirectbr (select cond, blockaddress(@fn, BlockA),
blockaddress(@fn, BlockB)))
into
(br cond, BlockA, BlockB).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120943 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-05 18:29:03 +00:00
Dan Gohman
4d70a29490
Factor out Instruction::isSafeToSpeculativelyExecute's code for
...
testing for dereferenceable pointers into a helper function,
isDereferenceablePointer. Teach it how to reason about GEPs
with simple non-zero indices.
Also eliminate ArgumentPromtion's IsAlwaysValidPointer,
which didn't check for weak externals or out of range gep
indices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118840 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 21:23:25 +00:00
Duncan Sands
5f28475b30
Fix PR8445: a block with no predecessors may be the entry block, in which case
...
it isn't unreachable and should not be zapped. The check for the entry block
was missing in one case: a block containing a unwind instruction. While there,
do some small cleanups: "M" is not a great name for a Function* (it would be
more appropriate for a Module*), change it to "Fn"; use Fn in more places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117224 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-24 12:23:30 +00:00
Duncan Sands
cdd4f8c7cb
Correct bogus module triple specifications.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112469 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-30 10:48:29 +00:00
Dan Gohman
7a4994356b
Instead, teach SimplifyCFG to trim non-address-taken blocks from
...
indirectbr destination lists.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111122 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-16 14:41:14 +00:00
Dan Gohman
e2c6d131d1
Teach SimplifyCFG how to simplify indirectbr instructions.
...
- Eliminate redundant successors.
- Convert an indirectbr with one successor into a direct branch.
Also, generalize SimplifyCFG to be able to be run on a function entry block.
It knows quite a few simplifications which are applicable to the entry
block, and it only needs a few checks to avoid trouble with the entry block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111060 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-14 00:29:42 +00:00
Benjamin Kramer
c125fedcc7
Test case for r105914.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105915 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-13 16:16:54 +00:00
Chris Lattner
c7d7e0cbe0
make simplifycfg insert an llvm.trap before the 'unreachable' it introduces
...
when it detects undefined behavior. llvm.trap generally codegens into some
thing really small (e.g. a 2 byte ud2 instruction on x86) and debugging this
sort of thing is "nontrivial". For example, we now compile:
void foo() { *(int*)0 = 42; }
into:
_foo:
pushl %ebp
movl %esp, %ebp
ud2
Some may even claim that this is a security hole, though that seems dubious
to me. This addresses rdar://7958343 - Optimizing away null dereference
potentially allows arbitrary code execution
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103356 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-08 22:15:59 +00:00
Gabor Greif
4e86da71b3
testcase for r99914, provided by baldrick!
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100043 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-31 20:37:13 +00:00
Dan Gohman
a9445e11c5
Floating-point add, sub, and mul are now spelled fadd, fsub, and fmul,
...
respectively.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97531 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-02 01:11:08 +00:00
Jakob Stoklund Olesen
58e9ee85fd
Teach SimplifyCFG about magic pointer constants.
...
Weird code sometimes uses pointer constants other than null. This patch
teaches SimplifyCFG to build switch instructions in those cases.
Code like this:
void f(const char *x) {
if (!x)
puts("null");
else if ((uintptr_t)x == 1)
puts("one");
else if (x == (char*)2 || x == (char*)3)
puts("two");
else if ((intptr_t)x == 4)
puts("four");
else
puts(x);
}
Now becomes a switch:
define void @f(i8* %x) nounwind ssp {
entry:
%magicptr23 = ptrtoint i8* %x to i64 ; <i64> [#uses=1]
switch i64 %magicptr23, label %if.else16 [
i64 0, label %if.then
i64 1, label %if.then2
i64 2, label %if.then9
i64 3, label %if.then9
i64 4, label %if.then14
]
Note that LLVM's own DenseMap uses magic pointers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95439 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-05 22:03:18 +00:00
Dan Gohman
aceba31b7a
Delete useless trailing semicolons.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92740 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05 17:55:26 +00:00
Chris Lattner
c17e2849d1
fix two bogus tests that the asmparser now rejects.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92303 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-30 05:54:51 +00:00
Chris Lattner
1a0e7081c3
Implement PR5795 by merging duplicated return blocks. This could go further
...
by merging all returns in a function into a single one, but simplifycfg
currently likes to duplicate the return (an unfortunate choice!)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91890 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-22 06:07:30 +00:00
Chris Lattner
42385b03aa
convert to filecheck
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91889 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-22 06:04:26 +00:00
Dan Gohman
14bbbf3168
Optimize test more.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86714 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10 21:02:18 +00:00
Chris Lattner
8fb02511d2
optimize test
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86672 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10 07:44:36 +00:00
Dan Gohman
438b583dbd
Revert r85667. LoopUnroll currently can't call utility functions which
...
auto-update the DominatorTree because it doesn't keep the DominatorTree
current while it works.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85670 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-31 17:33:01 +00:00
Dan Gohman
f230d8ad15
Merge the enhancements from LoopUnroll's FoldBlockIntoPredecessor into
...
MergeBlockIntoPredecessor. This makes SimplifyCFG slightly more aggressive,
and makes it unnecessary for LoopUnroll to have its own copy of this code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85667 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-31 16:08:00 +00:00
Dan Gohman
cf35517c4e
Add a testcase for the recent duplicate PHI elimination changes.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85636 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-30 23:16:10 +00:00
Chris Lattner
dac8bde235
if basic blocks are destroyed while there are *just* BlockAddress' hanging
...
around, then zap them. This is analogous to dangling constantexprs hanging
off functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85627 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-30 22:39:36 +00:00
Chris Lattner
11f15dbb28
change simplifycfg to not duplicate 'unwind' instructions. Hopefully
...
this will increase the likelihood of common code getting sunk towards
the unwind.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83996 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-13 18:13:05 +00:00
Chris Lattner
bf07da0e27
convert to filecheck
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83995 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-13 18:10:05 +00:00
Chris Lattner
f137f2f4c5
rename test
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83994 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-13 18:08:21 +00:00