Gordon Henriksen
db4f51e1b9
With this patch, the LowerGC transformation becomes the
...
ShadowStackCollector, which additionally has reduced overhead with
no sacrifice in portability.
Considering a function @fun with 8 loop-local roots,
ShadowStackCollector introduces the following overhead
(x86):
; shadowstack prologue
movl L_llvm_gc_root_chain$non_lazy_ptr, %eax
movl (%eax), %ecx
movl $___gc_fun, 20(%esp)
movl $0, 24(%esp)
movl $0, 28(%esp)
movl $0, 32(%esp)
movl $0, 36(%esp)
movl $0, 40(%esp)
movl $0, 44(%esp)
movl $0, 48(%esp)
movl $0, 52(%esp)
movl %ecx, 16(%esp)
leal 16(%esp), %ecx
movl %ecx, (%eax)
; shadowstack loop overhead
(none)
; shadowstack epilogue
movl 48(%esp), %edx
movl %edx, (%ecx)
; shadowstack metadata
.align 3
___gc_fun: # __gc_fun
.long 8
.space 4
In comparison to LowerGC:
; lowergc prologue
movl L_llvm_gc_root_chain$non_lazy_ptr, %eax
movl (%eax), %ecx
movl %ecx, 48(%esp)
movl $8, 52(%esp)
movl $0, 60(%esp)
movl $0, 56(%esp)
movl $0, 68(%esp)
movl $0, 64(%esp)
movl $0, 76(%esp)
movl $0, 72(%esp)
movl $0, 84(%esp)
movl $0, 80(%esp)
movl $0, 92(%esp)
movl $0, 88(%esp)
movl $0, 100(%esp)
movl $0, 96(%esp)
movl $0, 108(%esp)
movl $0, 104(%esp)
movl $0, 116(%esp)
movl $0, 112(%esp)
; lowergc loop overhead
leal 44(%esp), %eax
movl %eax, 56(%esp)
leal 40(%esp), %eax
movl %eax, 64(%esp)
leal 36(%esp), %eax
movl %eax, 72(%esp)
leal 32(%esp), %eax
movl %eax, 80(%esp)
leal 28(%esp), %eax
movl %eax, 88(%esp)
leal 24(%esp), %eax
movl %eax, 96(%esp)
leal 20(%esp), %eax
movl %eax, 104(%esp)
leal 16(%esp), %eax
movl %eax, 112(%esp)
; lowergc epilogue
movl 48(%esp), %edx
movl %edx, (%ecx)
; lowergc metadata
(none)
llvm-svn: 45670
2008-01-07 01:30:53 +00:00
Duncan Sands
fd975e4b3d
The transform that tries to turn calls to bitcast functions into
...
direct calls bails out unless caller and callee have essentially
equivalent parameter attributes. This is illogical - the callee's
attributes should be of no relevance here. Rework the logic, which
incidentally fixes a crash when removed arguments have attributes.
llvm-svn: 45658
2008-01-06 18:27:01 +00:00
Duncan Sands
b8489f09a2
When transforming a call to a bitcast function into
...
a direct call with cast parameters and cast return
value (if any), instcombine was prepared to cast any
non-void return value into any other, whether castable
or not. Add a new predicate for testing whether casting
is valid, and check it both for the return value and
(as a cleanup) for the parameters.
llvm-svn: 45657
2008-01-06 10:12:28 +00:00
Chris Lattner
7e1c3aa702
remove a couple more unsafe xforms in the face of overflow.
...
llvm-svn: 45613
2008-01-05 01:22:42 +00:00
Chris Lattner
983697dfac
remove the (x-y) < 0 comparison xform, it miscompiles
...
things that are not equality comparisons, for example:
(2147479553+4096)-2147479553 < 0 != (2147479553+4096) < 2147479553
llvm-svn: 45612
2008-01-05 01:18:20 +00:00
Wojciech Matyjewicz
9ec15f974f
fix typo
...
llvm-svn: 45594
2008-01-04 20:02:18 +00:00
Chris Lattner
ad9a6ccb83
Remove attribution from file headers, per discussion on llvmdev.
...
llvm-svn: 45418
2007-12-29 20:36:04 +00:00
Chris Lattner
8193d4af33
remove attribution from lib Makefiles.
...
llvm-svn: 45415
2007-12-29 20:09:26 +00:00
Christopher Lamb
dfad5f19b4
Disable null pointer folding transforms for non-generic address spaces. This should probably be a target-specific predicate based on address space. That way for targets where this isn't applicable the predicate can be optimized away.
...
llvm-svn: 45403
2007-12-29 07:56:53 +00:00
Owen Anderson
ebd3e9c500
Repair a transform that Chris noticed a bug in. Thanks to Nicholas for pointing out my stupid mistakes when writing this patch. :-)
...
llvm-svn: 45384
2007-12-28 07:42:12 +00:00
Chris Lattner
2456399ce5
disable this instcombine xform, it miscompiles:
...
define i32 @main() {
entry:
%z = alloca i32 ; <i32*> [#uses=2]
store i32 0, i32* %z
%tmp = load i32* %z ; <i32> [#uses=1]
%sub = sub i32 %tmp, 1 ; <i32> [#uses=1]
%cmp = icmp ult i32 %sub, 0 ; <i1> [#uses=1]
%retval = select i1 %cmp, i32 1, i32 0 ; <i32> [#uses=1]
ret i32 %retval
}
into ret 1, instead of ret 0.
Christopher, please investigate.
llvm-svn: 45383
2007-12-28 06:24:31 +00:00
Chris Lattner
90df7f7424
Don't break critical edges for single-bb loops, this helps with PR1877, though
...
it is only a partial fix. This change is noise for most programs, but
speeds up Shootout-C++/matrix by 20%, Ptrdist/ks by 24%, smg2000 by 8%,
hexxagon by 9%, bzip2 by 9% (not sure I trust this), ackerman by 13%, etc.
OTOH, it slows down Shootout/fib2 by 40% (I'll update PR1877 with this info).
llvm-svn: 45354
2007-12-25 19:06:45 +00:00
Chris Lattner
7e1e1f2933
add a -backedge-hack llc-beta option to codegenprepare.
...
When specified, don't split backedges of single-bb loops.
This helps address PR1877
llvm-svn: 45344
2007-12-24 19:32:55 +00:00
Chris Lattner
d64df490ca
implement InstCombine/shift-trunc-shift.ll. This allows
...
us to compile:
#include <math.h>
int t1(double d) { return signbit(d); }
into:
_t1:
movd %xmm0, %rax
shrq $63, %rax
ret
instead of:
_t1:
movd %xmm0, %rax
shrq $32, %rax
shrl $31, %eax
ret
on x86-64.
llvm-svn: 45311
2007-12-22 09:07:47 +00:00
Christopher Lamb
7ca648a7b1
Implement review feedback, including additional transforms
...
(icmp slt (sub A B) 1) -> (icmp sle A B)
icmp sgt (sub A B) -1) -> (icmp sge A B)
and add testcase.
llvm-svn: 45256
2007-12-20 07:21:11 +00:00
Evan Cheng
eb07401701
Clean up previous patch: PHI uses should not prevent iv reuse if all other uses are addresses. This trades a constant multiply for one fewer iv.
...
llvm-svn: 45251
2007-12-20 02:20:53 +00:00
Chris Lattner
1a386cbdae
simplify this code with the new m_Zero() pattern. Make sure the select only
...
has a single use, and generalize it to not require N to be a constant.
llvm-svn: 45250
2007-12-20 01:56:58 +00:00
Evan Cheng
cf7b6b419a
Allow iv reuse if the user is a PHI node which is in turn used as addresses.
...
llvm-svn: 45230
2007-12-19 23:33:23 +00:00
Duncan Sands
56f3add5b7
When inlining through an 'nounwind' call, mark inlined
...
calls 'nounwind'. It is important for correct C++
exception handling that nounwind markings do not get
lost, so this transformation is actually needed for
correctness.
llvm-svn: 45218
2007-12-19 21:13:37 +00:00
Christopher Lamb
be0cbc7e92
Fold subtracts into integer compares vs. zero. This improves generate code for this case on X86
...
from
_foo:
movl $99, %ecx
movl 4(%esp), %eax
subl %eax, %ecx
xorl %edx, %edx
testl %ecx, %ecx
cmovs %edx, %eax
ret
to
_foo:
xorl %ecx, %ecx
movl 4(%esp), %eax
cmpl $99, %eax
cmovg %ecx, %eax
ret
llvm-svn: 45173
2007-12-18 21:32:20 +00:00
Christopher Lamb
051a1320e8
Fix comments
...
llvm-svn: 45170
2007-12-18 20:33:11 +00:00
Christopher Lamb
d56318b885
Remove an orthogonal transformation of the selection condition from my most recent submission.
...
llvm-svn: 45169
2007-12-18 20:30:28 +00:00
Duncan Sands
242f80be86
Rename isNoReturn to doesNotReturn, and isNoUnwind to
...
doesNotThrow.
llvm-svn: 45160
2007-12-18 09:59:50 +00:00
Christopher Lamb
437b4d229e
Fix typos.
...
llvm-svn: 45159
2007-12-18 09:45:40 +00:00
Christopher Lamb
aeb76743dc
Fold certain additions through selects (and their compares) so as to eliminate subtractions. This code is often produced by the SMAX expansion in SCEV.
...
This implements test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
llvm-svn: 45158
2007-12-18 09:34:41 +00:00
David Greene
3f3a521a33
Get rid of annoying spaces.
...
llvm-svn: 45100
2007-12-17 17:40:29 +00:00
David Greene
8fda00ca05
Fix GLIBCXX_DEBUG errors. Erase invalidates std::vector iterators
...
passed the erased element.
llvm-svn: 45099
2007-12-17 17:39:51 +00:00
Christopher Lamb
a608afb52e
Change the PointerType api for creating pointer types. The old functionality of PointerType::get() has become PointerType::getUnqual(), which returns a pointer in the generic address space. The new prototype of PointerType::get() requires both a type and an address space.
...
llvm-svn: 45082
2007-12-17 01:12:55 +00:00
Duncan Sands
bf62f62058
Make instcombine promote inline asm calls to 'nounwind'
...
calls. Remove special casing of inline asm from the
inliner. There is a potential problem: the verifier
rejects invokes of inline asm (not sure why). If an
asm call is not marked "nounwind" in some .ll, and
instcombine is not run, but the inliner is run, then
an illegal module will be created. This is bad but
I'm not sure what the best approach is. I'm tempted
to remove the check in the verifier...
llvm-svn: 45073
2007-12-16 15:51:49 +00:00
Evan Cheng
4acb4eb95e
Fix typo.
...
llvm-svn: 44997
2007-12-13 07:50:36 +00:00
Evan Cheng
a152909956
Be extra careful with extension use optimation. Now turned on by default.
...
llvm-svn: 44981
2007-12-13 03:32:53 +00:00
Wojciech Matyjewicz
8bb1d9e67c
1. "Upgrage" comments.
...
2. Using zero-extended value of Scale and unsigned division is safe provided
that Scale doesn't have the sign bit set.
Previously these 2 instructions:
%p = bitcast [100 x {i8,i8,i8}]* %x to i8*
%q = getelementptr i8* %p, i32 -4
were combined into:
%q = getelementptr [100 x { i8, i8, i8 }]* %x, i32 0,
i32 1431655764, i32 0
what was incorrect.
llvm-svn: 44936
2007-12-12 15:21:32 +00:00
Evan Cheng
bb418c4551
Don't muck with phi nodes; bug fixes.
...
llvm-svn: 44905
2007-12-12 02:53:41 +00:00
Evan Cheng
d6ecb2e58d
Bug fix. Only safe to perform extension uses optimization if the source of extension is also defined in the same BB as the extension.
...
llvm-svn: 44896
2007-12-12 00:51:06 +00:00
Duncan Sands
b7ac459292
Make PruneEH update the nounwind/noreturn attributes
...
on functions as it calculates them.
llvm-svn: 44802
2007-12-10 19:09:40 +00:00
Owen Anderson
e3de18ac1d
Fix several cache coherence bugs in MemDep/GVN that were found. Also add some (disabled) debugging code
...
to make such problems easier to diagnose in the future, written by Duncan Sands.
llvm-svn: 44695
2007-12-08 01:37:09 +00:00
Chris Lattner
861df2f4e9
simplify some code.
...
llvm-svn: 44655
2007-12-06 06:25:04 +00:00
Chris Lattner
1f2a96f9c1
move some ashr-specific code out of commonShiftTransforms into visitAShr.
...
llvm-svn: 44650
2007-12-06 01:59:46 +00:00
Evan Cheng
9e69c0ada8
If both result of the {s|z}xt and its source are live out, rewrite all uses of the source with result of extension.
...
llvm-svn: 44643
2007-12-05 23:58:20 +00:00
Duncan Sands
1e2e4972ff
Rather than having special rules like "intrinsics cannot
...
throw exceptions", just mark intrinsics with the nounwind
attribute. Likewise, mark intrinsics as readnone/readonly
and get rid of special aliasing logic (which didn't use
anything more than this anyway).
llvm-svn: 44544
2007-12-03 20:06:50 +00:00
Chris Lattner
0c41f32943
update file comment.
...
llvm-svn: 44543
2007-12-03 19:43:18 +00:00
Devang Patel
c47f68e747
If ExitValue operand is also defined in Loop header then
...
insert new ExitValue after this operand definition.
This fixes PR1828.
llvm-svn: 44539
2007-12-03 19:17:21 +00:00
Duncan Sands
14f11d6836
Integrate the readonly/readnone logic more deeply
...
into alias analysis. This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter. These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function. Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite. To reduce the
chance of misuse it is now protected.
llvm-svn: 44487
2007-12-01 07:51:45 +00:00
Owen Anderson
3b893e1f84
Fix a miscompilation in spiff on PPC.
...
llvm-svn: 44437
2007-11-29 18:02:22 +00:00
Duncan Sands
1b0feb42e2
Add some convenience methods for querying attributes, and
...
use them.
llvm-svn: 44403
2007-11-28 17:07:01 +00:00
Duncan Sands
3602011bec
Fix PR1146: parameter attributes are longer part of
...
the function type, instead they belong to functions
and function calls. This is an updated and slightly
corrected version of Reid Spencer's original patch.
The only known problem is that auto-upgrading of
bitcode files doesn't seem to work properly (see
test/Bitcode/AutoUpgradeIntrinsics.ll). Hopefully
a bitcode guru (who might that be? :) ) will fix it.
llvm-svn: 44359
2007-11-27 13:23:08 +00:00
Owen Anderson
43d4a82d4b
Make LoopInfoBase more generic, in preparation for having MachineLoopInfo. This involves a small interface change.
...
llvm-svn: 44348
2007-11-27 03:43:35 +00:00
Owen Anderson
2aa0218a6c
Fix another bug that was causing siod to fail.
...
llvm-svn: 44325
2007-11-26 07:17:19 +00:00
Owen Anderson
05275b7b14
Allow GVN to eliminate read-only function calls when it can detect that they are redundant.
...
llvm-svn: 44323
2007-11-26 02:26:36 +00:00
Anton Korobeynikov
14246a2eba
Remove another leak. Due to some reason AliasSetTracker didn't had any dtor...
...
llvm-svn: 44320
2007-11-25 23:52:02 +00:00