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3738 Commits

Author SHA1 Message Date
Chris Lattner
2940c5c56d Implement PR1795, an instcombine hack for forming GEPs with integer pointer arithmetic. 
llvm-svn: 45745
 2008-01-08 07:23:51 +00:00
Duncan Sands
b18c30acec Small cleanup for handling of type/parameter attribute 
incompatibility.

llvm-svn: 45704
 2008-01-07 17:16:06 +00:00
Gordon Henriksen
efb08802ec Deleting an empty file. Thanks, /usr/bin/patch! 
llvm-svn: 45675
 2008-01-07 02:29:04 +00:00
Gordon Henriksen
6047b6e140 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
404eb05247 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
55e5090fe8 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
e666bc272d remove a couple more unsafe xforms in the face of overflow. 
llvm-svn: 45613
 2008-01-05 01:22:42 +00:00
Chris Lattner
db026d703b 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
30e434569e fix typo 
llvm-svn: 45594
 2008-01-04 20:02:18 +00:00
Chris Lattner
bdd6acfb59 Fix PR1896 
llvm-svn: 45568
 2008-01-04 05:04:53 +00:00
Chris Lattner
f391883670 don't hoist FP additions into unconditional adds + selects. This 
could theoretically introduce a trap, but is also a performance issue.
This speeds up ptrdist/ks by 8%.

llvm-svn: 45533
 2008-01-03 07:25:26 +00:00
Chris Lattner
d2b0e15535 add missing #include 
llvm-svn: 45516
 2008-01-02 23:41:05 +00:00
Chris Lattner
f3ebc3f3d2 Remove attribution from file headers, per discussion on llvmdev. 
llvm-svn: 45418
 2007-12-29 20:36:04 +00:00
Chris Lattner
a087a8d2ce remove attribution from lib Makefiles. 
llvm-svn: 45415
 2007-12-29 20:09:26 +00:00
Christopher Lamb
b053b80b79 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
Chris Lattner
e96658392d dead calls to llvm.stacksave can be deleted, even though they 
have potential side-effects.

llvm-svn: 45392
 2007-12-29 00:59:12 +00:00
Owen Anderson
7363914ef7 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
5179819beb 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
Gordon Henriksen
520e64c0c2 Fixing several transforms which would drop the collector attribute 
when copying functions.

llvm-svn: 45356
 2007-12-25 22:16:06 +00:00
Chris Lattner
ef1bbfc762 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
Gordon Henriksen
b969c5981b GC poses hazards to the inliner. Consider: 
define void @f() {
            ...
            call i32 @g()
            ...
    }

    define void @g() {
            ...
    }

The hazards are:

  - @f and @g have GC, but they differ GC. Inlining is invalid. This
    may never occur.
  - @f has no GC, but @g does. g's GC must be propagated to @f.

The other scenarios are safe:

  - @f and @g have the same GC.
  - @f and @g have no GC.
  - @g has no GC.

This patch adds inliner checks for the former two scenarios.

llvm-svn: 45351
 2007-12-25 03:10:07 +00:00
Chris Lattner
62a806d565 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
74b2ab59fd 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
Devang Patel
7a2c66b11e If succ has succ itself as one of the predecessors then do 
not merge current bb and succ even if bb's terminator is
unconditional branch to succ.

llvm-svn: 45305
 2007-12-22 01:32:53 +00:00
Duncan Sands
6a7703ed63 Make DAE not wipe out attributes on calls, and not drop 
return attributes on the floor.  In the case of a call
to a varargs function where the varargs arguments are
being removed, any call attributes on those arguments
need to be dropped.  I didn't do this because I plan to
make it illegal to have such attributes (see next patch).
With this change, compiling the gcc filter2 eh test at -O0
and then running opt -std-compile-opts on it results in
a correctly working program (compiling at -O1 or higher
results in the test failing due to a problem with how we
output eh info into the IR).

llvm-svn: 45285
 2007-12-21 19:16:16 +00:00
Christopher Lamb
7d82bc46b8 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
26ee54eb05 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
16a51da0e2 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
e2a8ba7fec 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
aa31b92508 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
f00ac6dd93 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
b7016c53d1 Fix comments 
llvm-svn: 45170
 2007-12-18 20:33:11 +00:00
Christopher Lamb
74dbad9216 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
3353ed09ac Rename isNoReturn to doesNotReturn, and isNoUnwind to 
doesNotThrow.

llvm-svn: 45160
 2007-12-18 09:59:50 +00:00
Christopher Lamb
30291f4a30 Fix typos. 
llvm-svn: 45159
 2007-12-18 09:45:40 +00:00
Christopher Lamb
8b09a464b4 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
Duncan Sands
b5a79d0eaa Make invokes of inline asm legal. Teach codegen 
how to lower them (with no attempt made to be
efficient, since they should only occur for
unoptimized code).

llvm-svn: 45108
 2007-12-17 18:08:19 +00:00
David Greene
71eae8a5ee GLIBCXX_DEBUG fix. std::vector<>::end() is invalidated by erase. 
llvm-svn: 45101
 2007-12-17 17:42:03 +00:00
David Greene
c4a80fb574 Get rid of annoying spaces. 
llvm-svn: 45100
 2007-12-17 17:40:29 +00:00
David Greene
2a5967b36a 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
edf0788758 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
56ed48036b Revert this part of r45073 until the verifier is 
changed not to reject invoke of inline asm.

llvm-svn: 45077
 2007-12-16 21:01:21 +00:00
Duncan Sands
8e4847ee95 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
2011df4e39 Fix typo. 
llvm-svn: 44997
 2007-12-13 07:50:36 +00:00
Evan Cheng
37c36ed79a Be extra careful with extension use optimation. Now turned on by default. 
llvm-svn: 44981
 2007-12-13 03:32:53 +00:00
Chris Lattner
f0fbf077d2 Fix for edge profiling, patch by 'Marc' for PR1857 
llvm-svn: 44965
 2007-12-13 00:04:46 +00:00
Wojciech Matyjewicz
309e5a723b 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
63d33cfd2b Don't muck with phi nodes; bug fixes. 
llvm-svn: 44905
 2007-12-12 02:53:41 +00:00
Evan Cheng
7bc8942532 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
Chris Lattner
d2265b45ae Fix PR1850 by removing an unsafe transformation from VMCore/ConstantFold.cpp. 
Reimplement the xform in Analysis/ConstantFolding.cpp where we can use
targetdata to validate that it is safe.  While I'm in there, fix some const
correctness issues and generalize the interface to the "operand folder".

llvm-svn: 44817
 2007-12-10 22:53:04 +00:00