Commit Graph

3747 Commits

Author SHA1 Message Date
Duncan Sands 5b721fc21d When DAE drops the varargs part of a function, ensure any
attributes on the vararg call arguments are also dropped.

llvm-svn: 45892
2008-01-11 23:13:45 +00:00
Chris Lattner b5bd924e83 Teach argpromote to ruthlessly hack small byval structs when it can
get away with it, which exposes opportunities to eliminate the memory
objects entirely.  For example, we now compile byval.ll to:

define internal void @f1(i32 %b.0, i64 %b.1) {
entry:
	%tmp2 = add i32 %b.0, 1		; <i32> [#uses=0]
	ret void
}

define i32 @main() nounwind  {
entry:
	call void @f1( i32 1, i64 2 )
	ret i32 0
}

This seems like it would trigger a lot for code that passes around small
structs (e.g. SDOperand's or _Complex)...

llvm-svn: 45886
2008-01-11 22:31:41 +00:00
Chris Lattner b66fbdde42 Use smallptrset instead of std::set for efficiency.
llvm-svn: 45878
2008-01-11 19:36:30 +00:00
Chris Lattner 4a70261f00 a byval argument is guaranteed to be valid to load.
llvm-svn: 45877
2008-01-11 19:34:32 +00:00
Chris Lattner 4062a625e5 Update this code to use eraseFromParent where possible. Compute
whether an argument is byval and pass into isSafeToPromoteArgument.

llvm-svn: 45876
2008-01-11 19:20:39 +00:00
Chris Lattner e736e55d3c replace a loop with a constant time check.
llvm-svn: 45875
2008-01-11 18:55:10 +00:00
Chris Lattner 669e7054ca another minor datastructure tweak.
llvm-svn: 45874
2008-01-11 18:47:45 +00:00
Chris Lattner a8ba28f6e4 start using smallvector to avoid vector heap thrashing.
llvm-svn: 45873
2008-01-11 18:43:58 +00:00
Chris Lattner 908117bf69 When inlining a functino with a byval argument, make an explicit
copy of it in case the callee modifies the struct.

llvm-svn: 45853
2008-01-11 06:09:30 +00:00
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