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Commit Graph

5996 Commits

Author SHA1 Message Date
Dale Johannesen
4510149fd2 Fix unsigned->ppcf128 conversion.
llvm-svn: 58856
2008-11-07 19:11:43 +00:00
Bill Wendling
dea20bc52f Refactor code that adjusts the offsets of stack objects.
llvm-svn: 58829
2008-11-07 01:48:58 +00:00
Dale Johannesen
89da8440e1 When we're doing a compare of load-AND-constant to 0
(e.g. a bitfield test) narrow the load as much as possible.
The has the potential to avoid unnecessary partial-word
load-after-store conflicts, which cause stalls on several targets.
Also a size win on x86 (testb vs testl).

llvm-svn: 58825
2008-11-07 01:28:02 +00:00
Bill Wendling
3fe9fef0da - Modify the stack protector algorithm so that the stack slot is allocated in
LLVM IR code and not in the selection DAG ISel. This is a cleaner solution.

- Fix the heuristic for determining if protectors are necessary. The previous
  one wasn't checking the proper type size.

llvm-svn: 58824
2008-11-07 01:23:58 +00:00
Bill Wendling
54a5c87823 Remove unneeded header file.
llvm-svn: 58823
2008-11-06 23:56:59 +00:00
Bill Wendling
70e06738b4 Don't build a vector of returns. Just modify the Function in the loop.
llvm-svn: 58822
2008-11-06 23:55:49 +00:00
Mon P Wang
888f4e6fb0 Fixed scalarizing an extract subvector and prevent an infinite loop
when simplify a vector. 

llvm-svn: 58820
2008-11-06 22:52:21 +00:00
Bill Wendling
1e6576e1e0 The size limit is for individual arrays. So if any array has more than 8 bytes
in it, then emit stack protectors.

llvm-svn: 58819
2008-11-06 22:18:44 +00:00
Bill Wendling
26eadae94d Don't recalculate the stack position of the stack protector.
llvm-svn: 58815
2008-11-06 21:37:09 +00:00
Devang Patel
8640fd500a Emit label for llvm.dbg.func.start of the inlined function.
llvm-svn: 58814
2008-11-06 21:28:20 +00:00
Duncan Sands
50acaf2367 Formating/comment changes - no functionality change.
llvm-svn: 58801
2008-11-06 08:51:32 +00:00
Bill Wendling
b6e2d60e7a - Rename stackprotector_{prologue,epilogue} to stackprotector_{create,check}.
- Get rid of "HasStackProtector" in MachineFrameInfo.
- Modify intrinsics to tell which are doing what with memory.

llvm-svn: 58799
2008-11-06 07:23:03 +00:00
Mon P Wang
41f90a3ee5 Widening cleanup
llvm-svn: 58796
2008-11-06 05:31:54 +00:00
Bill Wendling
489791a127 Adjust the stack protector heuristic to care about only arrays or calls to
"alloca".

llvm-svn: 58792
2008-11-06 02:38:58 +00:00
Bill Wendling
08905ed703 Implement the stack protector stack accesses via intrinsics:
- stackprotector_prologue creates a stack object and stores the guard there.

- stackprotector_epilogue reads the stack guard from the stack position created
  by stackprotector_prologue.

- The PrologEpilogInserter was changed to make sure that the stack guard is
  first on the stack frame.

llvm-svn: 58791
2008-11-06 02:29:10 +00:00
Devang Patel
ec135e1f33 Emit label for llvm.dbg.func.start of the inlined function.
llvm-svn: 58786
2008-11-06 00:30:09 +00:00
Duncan Sands
f56e2fb5c2 Fix thinko in ppcf128 expansion of truncating store.
llvm-svn: 58753
2008-11-05 07:17:27 +00:00
Evan Cheng
1bde698192 Type of shuffle mask has changed.
llvm-svn: 58751
2008-11-05 06:04:18 +00:00
Bill Wendling
986e386794 Remove dead variable.
llvm-svn: 58741
2008-11-05 00:56:35 +00:00
Bill Wendling
8c86d20576 Simplify the allocated size calculation.
llvm-svn: 58740
2008-11-05 00:54:27 +00:00
Bill Wendling
2461aaa183 Fix comment
llvm-svn: 58739
2008-11-05 00:46:15 +00:00
Owen Anderson
df29b0d7b2 Use the new predicate to control when we do prealloc splitting. Fix a small bug.
llvm-svn: 58738
2008-11-05 00:32:13 +00:00
Bill Wendling
e73f31f526 Some code simplification. It now doesn't generate a prologue if the epilogue
isn't going to be generated.

llvm-svn: 58734
2008-11-05 00:00:21 +00:00
Bill Wendling
214f515922 Small simplification of the stack guard type.
llvm-svn: 58728
2008-11-04 22:54:43 +00:00
Bill Wendling
79a8798e07 - Add a "getOrInsertGlobal" method to the Module class. This acts similarly to
"getOrInsertFunction" in that it either adds a new declaration of the global
  and returns it, or returns the current one -- optionally casting it to the
  correct type.
- Use the new getOrInsertGlobal in the stack protector code.
- Use "splitBasicBlock" in the stack protector code.

llvm-svn: 58727
2008-11-04 22:51:24 +00:00
Owen Anderson
2ed3bc9016 First pass at checking for the creation of a new join point when doing pre-alloc splitting. This is not turned on yet.
llvm-svn: 58726
2008-11-04 22:22:41 +00:00
Bill Wendling
ae168b2c83 Update in response to feedback from Chris:
- Use enums instead of magic numbers.

- Rework algorithm to use the bytes size from the target to determine when to
  emit stack protectors.

- Get rid of "propolice" in any comments.

- Renamed an option to its expanded form.

- Other miscellanenous changes.

More changes will come after this.

llvm-svn: 58723
2008-11-04 21:53:09 +00:00
Dale Johannesen
eee3a8a2e0 80 columns
llvm-svn: 58717
2008-11-04 20:52:49 +00:00
Duncan Sands
aed2dfe3f6 Fix typo. Patch by nlewycky.
llvm-svn: 58709
2008-11-04 18:05:30 +00:00
Duncan Sands
58ebf09772 Fix PR3011: LegalizeTypes support for scalarizing
SELECT_CC.

llvm-svn: 58706
2008-11-04 17:31:08 +00:00
Nuno Lopes
0995eae6b8 fix leakage of IfcvtTokens
llvm-svn: 58690
2008-11-04 13:02:59 +00:00
Oscar Fuentes
9f6d4e7fb0 CMake: Updated list of source files.
llvm-svn: 58676
2008-11-04 03:24:04 +00:00
Bill Wendling
0f3f36688b Initial checkin for stack protectors. Here's what it does:
* The prologue is modified to read the __stack_chk_guard global and insert it
  onto the stack.

* The epilogue is modified to read the stored guard from the stack and compare
  it to the original __stack_chk_guard value. If they differ, then the
  __stack_chk_fail() function is called.

* The stack protector needs to be first on the stack (after the parameters) to
  catch any stack-smashing activities.

Front-end support will follow after a round of beta testing.

llvm-svn: 58673
2008-11-04 02:10:20 +00:00
Dale Johannesen
d9906b90d0 Fix some ppcf128 regressions: make ExpandFloatRes_LOAD
work correctly, and bring over a late change to ppcf128
SetCC handling.

llvm-svn: 58642
2008-11-03 20:47:45 +00:00
Duncan Sands
8a94be8c5b Make VAARG promotion work correctly with large funky
sized integers like i129, and also reduce the number
of assumptions made about how vaarg is implemented.
This still doesn't work correctly for small integers
like (eg) i1 on x86, since x86 passes each of them
(essentially an i8) in a 4 byte stack slot, so the
pointer needs to be advanced by 4 bytes not by 1 byte
as now.  But this is no longer a LegalizeTypes problem
(it was also wrong in LT before): it is a bug in the
operation expansion in LegalizeDAG: now LegalizeTypes
turns an i1 vaarg into an i8 vaarg which would work
fine if only the i8 vaarg was turned into correct code
later.

llvm-svn: 58635
2008-11-03 20:22:12 +00:00
Duncan Sands
a9047944bc Make VAARG work with x86 long double (which is
10 bytes long, but is passed in 12/16 bytes).

llvm-svn: 58608
2008-11-03 11:51:11 +00:00
Matthijs Kooijman
a91b759ccf Make MachineFrameInfo::print not crash when no TargetFrameInfo is available.
llvm-svn: 58606
2008-11-03 11:16:43 +00:00
Owen Anderson
6d82fd0e8e Revert my last patch until I consult with Evan about it.
llvm-svn: 58591
2008-11-03 02:33:28 +00:00
Owen Anderson
146d114669 Don't do pre-splitting if doing so would create a value join that did not
exist before.  Updating the live intervals in that care is tricky in the general
case.

Evan, if you see a tighter guard condition for this, let me know.

llvm-svn: 58560
2008-11-02 08:08:18 +00:00
Mon P Wang
0d137a1c51 Added interface to allow clients to create a MemIntrinsicNode for
target intrinsics that touches memory

llvm-svn: 58548
2008-11-01 20:24:53 +00:00
Anton Korobeynikov
705faa7911 Invalidate debug/eh/gc labels when unreachable MBB is deleted.
Based on patch by Martin Nowack!

llvm-svn: 58536
2008-10-31 20:08:30 +00:00
Dan Gohman
f46431018c Remove some unused virtual function bodies.
llvm-svn: 58524
2008-10-31 19:06:33 +00:00
Bill Wendling
f8f6ed82f1 Revert r58489. It isn't correct for all cases.
llvm-svn: 58523
2008-10-31 18:30:19 +00:00
Evan Cheng
d3b31c4fe1 Add a fixme.
llvm-svn: 58514
2008-10-31 16:41:59 +00:00
Duncan Sands
d2500010a3 Add a bunch of libcalls for ppcf128 that were somehow
completely forgotten about when writing LegalizeTypes.

llvm-svn: 58508
2008-10-31 14:06:52 +00:00
Bill Wendling
0f1f4f8bb1 Don't skip over all "terminator" instructions when determining where to put the
callee-saved restore code. It could skip over conditional jumps
accidentally. Instead, just skip the "return" instructions.

llvm-svn: 58489
2008-10-31 04:00:23 +00:00
Duncan Sands
615567edc6 Fix PR2986: do not use a potentially illegal
type for the shift amount type.  Add a check
that shifts and rotates use the type returned
by getShiftAmountTy for the amount.  This
exposed some problems in CellSPU and PPC,
which have already been fixed.

llvm-svn: 58455
2008-10-30 20:26:50 +00:00
Mon P Wang
64e6e15947 Add missing vsetcc expansion for widening
llvm-svn: 58443
2008-10-30 18:21:52 +00:00
Mon P Wang
d7e34cd378 Add initial support for vector widening. Logic is set to widen for X86.
One will only see an effect if legalizetype is not active.  Will move
support to LegalizeType soon.

llvm-svn: 58426
2008-10-30 08:01:45 +00:00
Duncan Sands
4f4d9d24a4 Uniformize capitalization of NodeId.
llvm-svn: 58386
2008-10-29 17:52:12 +00:00
Duncan Sands
fd032c5bef Fix PR2977: LegalizeTypes support for expanding
VAARG.

llvm-svn: 58379
2008-10-29 14:25:28 +00:00
Duncan Sands
ada9e7a16d Add sanity checking for BUILD_PAIR (I noticed the
other day that PPC custom lowering could create
a BUILD_PAIR of two f64 with a result type of...
f64! - already fixed).  Fix a place that triggers
the sanity check.

llvm-svn: 58378
2008-10-29 14:22:20 +00:00
Evan Cheng
6125b9e097 - More pre-split fixes: spill slot live interval computation bug; restore point bug.
- If a def is spilt, remember its spill index to allow its reuse.

llvm-svn: 58375
2008-10-29 08:39:34 +00:00
Duncan Sands
3faee6737e Fix a FIXME: in ReplaceNodeWith, if the new node
is morphed by AnalyzeNewNode into a previously
processed node, and different result values of
that node are remapped to values with different
nodes, then we could end up using wrong values
here [we were assuming that all results remap
to values with the same underlying node].  This
seems theoretically possible, but I don't have
a testcase.  The meat of the patch is in the
changes to AnalyzeNewNode/AnalyzeNewValue and
ReplaceNodeWith.  While there, I changed names
like RemapNode to RemapValue, since it really
remaps values.  To tell the truth, I would be
much happier if we were only remapping nodes
(it would simplify a bunch of logic, and allow
for some cute speedups) but I haven't yet worked
out how to do that.

llvm-svn: 58372
2008-10-29 06:42:19 +00:00
Duncan Sands
cb5432cdb4 Fix 80 column violations.
llvm-svn: 58371
2008-10-29 06:33:00 +00:00
Duncan Sands
790e7e655b Fix 80 column violations.
llvm-svn: 58370
2008-10-29 06:31:03 +00:00
Evan Cheng
cd21d433bb - Rewrite code that update register live interval that's split.
- Create and update spill slot live intervals.
- Lots of bug fixes.

llvm-svn: 58367
2008-10-29 05:06:14 +00:00
Dan Gohman
eb869eb116 Take Chris' suggestion and define EnableFastISelVerbose and
EnableFastISelAbort variables for Release mode instead of
using ifdefs in the code.

llvm-svn: 58350
2008-10-28 20:35:31 +00:00
Dan Gohman
5a2a8f4b9b Protect the code for fast-isel debugging with #ifndef NDEBUG.
llvm-svn: 58340
2008-10-28 19:08:46 +00:00
Duncan Sands
a64641fbd2 Fix darwin ppc llvm-gcc build breakage: intercept
ppcf128 to i32 conversion and expand it into a code
sequence like in LegalizeDAG.  This needs custom
ppc lowering of FP_ROUND_INREG, so turn that on and
make it work with LegalizeTypes.  Probably PPC should
simply custom lower the original conversion.

llvm-svn: 58329
2008-10-28 15:00:32 +00:00
Duncan Sands
ce82e0aa82 Fix a testcase provided by Bill in which the node
id could end up being wrong mostly because of
forgetting to remap new nodes that morphed into
processed nodes through CSE.

llvm-svn: 58323
2008-10-28 09:38:36 +00:00
Chris Lattner
508a62823e Don't produce invalid comparisons after legalize.
llvm-svn: 58320
2008-10-28 07:11:07 +00:00
Chris Lattner
e39269e22a fix some whitespace stuff
llvm-svn: 58319
2008-10-28 07:10:51 +00:00
Evan Cheng
8f9bfa5bff If def is in the same mbb as the barrier, spilt the value after the last use before the barrier.
llvm-svn: 58314
2008-10-28 05:28:21 +00:00
Evan Cheng
6242a4f47b Add command line option to limit the number splits to help debugging.
llvm-svn: 58312
2008-10-28 01:48:24 +00:00
Evan Cheng
9bbf76a1e9 Avoid putting a split past the end of the live range; always shrink wrap live interval in the barrier mbb.
llvm-svn: 58309
2008-10-28 00:47:49 +00:00
Evan Cheng
420490d6c4 Silence a bogus compile time warning.
llvm-svn: 58297
2008-10-27 23:29:28 +00:00
Evan Cheng
056ef89e68 Remove val# defined by a remat'ed def that is now dead.
llvm-svn: 58294
2008-10-27 23:21:01 +00:00
Ted Kremenek
03c067710c Fix bogus comparison of "const char *" with c-string literal. Use strcmp instead.
llvm-svn: 58290
2008-10-27 22:43:07 +00:00
David Greene
5015610892 Add setSubgraphColor to color an entire portion of a SelectionDAG. This
will be used to support debug features in TableGen.

llvm-svn: 58257
2008-10-27 18:17:03 +00:00
David Greene
78744a795a Fix PR2634. Create new virtual registers from spills early so that we
can give it the same stack slot as the spilled interval if it is folded.
This prevents the fold/unfold code from pointing to the wrong register.

llvm-svn: 58255
2008-10-27 17:38:59 +00:00
Duncan Sands
22451e0303 Fix UpdateNodeOperands so that it does CSE of calls
(and a bunch of other node types).  While there, I
added a doNotCSE predicate and used it to reduce code
duplication (some of the duplicated code was wrong...).
This fixes ARM/cse-libcalls.ll when using LegalizeTypes. 

llvm-svn: 58249
2008-10-27 15:30:53 +00:00
Duncan Sands
039edb065f Fix a bug in which a node could be added to the
worklist twice: UpdateNodeOperands could morph
a new node into a node already on the worklist.
We would then recalculate the NodeId for this
existing node and add it to the worklist.  The
testcase is ARM/cse-libcalls.ll, the problem
showing up once UpdateNodeOperands is taught to
do CSE for calls.

llvm-svn: 58246
2008-10-27 13:18:32 +00:00
Duncan Sands
a6bbc047d5 Turn on LegalizeTypes, the new type legalization
codegen infrastructure, by default.  Please report
any breakage to the mailing lists.

llvm-svn: 58232
2008-10-27 08:42:46 +00:00
Evan Cheng
3bcbccf563 For now, don't split live intervals around x87 stack register barriers. FpGET_ST0_80 must be right after a call instruction (and ADJCALLSTACKUP) so we need to find a way to prevent reload of x87 registers between them.
llvm-svn: 58230
2008-10-27 07:14:50 +00:00
Dale Johannesen
d0a0ce909b Increase default setting of tail-merge-threshold to
150, based on llvm-test measurements.

llvm-svn: 58225
2008-10-27 02:10:21 +00:00
Evan Cheng
8a7f04e7c2 Do not shrink wrap live interval in a mbb if it's livein any of its successor blocks. The mbb can be revisited again after all of the successors are processed.
llvm-svn: 58184
2008-10-26 07:49:03 +00:00
Evan Cheng
db1c135283 Handle cases where there aren't uses in the barrier mbb.
llvm-svn: 58174
2008-10-25 23:49:39 +00:00
Dan Gohman
e7c43e94b0 SDNodes may have at most one Flag result. Update this comment
to reflect that.

llvm-svn: 58145
2008-10-25 17:51:24 +00:00
Dan Gohman
66e878f316 Move the code that adds the DeadMachineInstructionElimPass from
target-independent code to target-specific code. This prevents it
from running on targets that aren't using fast-isel.

In addition to saving compile time, this addresses the problem
that not all targets are prepared for it. In order to use this
pass, all instructions must declare all their fixed uses and
defs of physical registers.

llvm-svn: 58144
2008-10-25 17:46:52 +00:00
Evan Cheng
0c78ace7dc If val# def is ~0U, meaning it's defined by a PHI, and it's previously split, spill before the barrier because it's impossible to determine if all the defs are spilled in the same spill slot.
llvm-svn: 58129
2008-10-25 00:52:41 +00:00
Evan Cheng
cfd2ecd29f Fix a pasto.
llvm-svn: 58102
2008-10-24 18:46:44 +00:00
Evan Cheng
efb8edb805 Fix a end() dereference; remove an abort() that wasn't meant to be left in.
llvm-svn: 58072
2008-10-24 05:53:44 +00:00
Evan Cheng
a7a0aabf99 Avoid splitting an interval multiple times; avoid splitting re-materializable val# (for now).
llvm-svn: 58068
2008-10-24 02:05:00 +00:00
Dale Johannesen
9edd60f710 Initialize uninitialized variable.
llvm-svn: 58057
2008-10-24 01:06:58 +00:00
Evan Cheng
c906d4938e Committing a good chunk of the pre-register allocation live interval splitting pass. It's handling simple cases and appear to do good things. Next: avoid splitting an interval multiple times; renumber registers when possible; record stack slot live intervals for coloring; rematerialize defs when possible.
llvm-svn: 58044
2008-10-23 20:43:13 +00:00
Duncan Sands
d4ea54fd77 Fix thinko - the operand number has nothing to do
with the result number.

llvm-svn: 58041
2008-10-23 19:34:23 +00:00
Duncan Sands
91535074e9 LegalizeTypes soft-float support for fpow.
llvm-svn: 57973
2008-10-22 11:49:09 +00:00
Duncan Sands
0d122150ce Be nice to CellSPU: for this target getSetCCResultType
may return i8, which can result in SELECT nodes for
which the type of the condition is i8, but there are
no patterns for select with i8 condition.  Tweak the
LegalizeTypes logic to avoid this as much as possible.
This isn't a real fix because it is still perfectly
possible to end up with such select nodes - CellSPU
needs to be fixed IMHO.

llvm-svn: 57968
2008-10-22 09:23:20 +00:00
Duncan Sands
ebf65ef3f9 Port from LegalizeDAG the logic to only generate
ADDC/ADDE/SUBC/SUBE if the target supports it.

llvm-svn: 57967
2008-10-22 09:07:29 +00:00
Duncan Sands
81c4c88859 Add some comments explaining the meaning of a boolean
that is not of type MVT::i1 in SELECT and SETCC nodes.
Relax the LegalizeTypes SELECT condition promotion
sanity checks to allow other condition types than i1.

llvm-svn: 57966
2008-10-22 09:06:24 +00:00
Duncan Sands
7ba0cc16c1 Temporarily allow the operands of a BUILD_VECTOR
to have a different type to the vector element
type.  This should be fairly harmless because in
the past guys like this were being built all over
the place (and were cleaned up when I added this
check).  The reason for relaxing this check is
that it helps LegalizeTypes legalize vector
shuffles: the mask is a BUILD_VECTOR that it is
*not always possible* to legalize while keeping it
a BUILD_VECTOR (vector_shuffle requires the mask
to be a BUILD_VECTOR, as opposed to a vector with
the right vector type).  With this check it is even
harder to legalize the mask - turning the check off
means that LegalizeTypes manages to legalize almost
all vector shuffles encountered in practice.  The
correct solution is to change vector_shuffle to be a
variadic node with the mask built into it as operands.
While waiting for that change, this hack stops the
problem with vector_shuffle from blocking the turning
on of LegalizeTypes.

llvm-svn: 57965
2008-10-22 09:00:33 +00:00
Daniel Dunbar
d1169ccaf2 Move Print*Pass to use raw_ostream.
llvm-svn: 57946
2008-10-22 03:25:22 +00:00
Daniel Dunbar
919ce3c16a Privatize PrintModulePass and PrintFunctionPass and add
createPrintModulePass and createPrintFunctionPass.
 - So clients who compile w/o RTTI can use them.

llvm-svn: 57933
2008-10-21 23:33:38 +00:00
Dale Johannesen
eb7e2deb1d Add an SSE2 algorithm for uint64->f64 conversion.
The same one Apple gcc uses, faster.  Also gets the
extreme case in gcc.c-torture/execute/ieee/rbug.c
correct which we weren't before; this is not
sufficient to get the test to pass though, there
is another bug.

llvm-svn: 57926
2008-10-21 20:50:01 +00:00
Dan Gohman
b6f073ce21 Fix SelectionDAGBuild lowering of Select instructions to
handle first-class aggregate values. Also, fix a bug in
the Ret handling for empty aggregates.

llvm-svn: 57925
2008-10-21 20:00:42 +00:00
Dan Gohman
847a83dbad Don't create TargetGlobalAddress nodes with offsets that don't fit
in the 32-bit signed offset field of addresses. Even though this
may be intended, some linkers refuse to relocate code where the
relocated address computation overflows.

Also, fix the sign-extension of constant offsets to use the
actual pointer size, rather than the size of the GlobalAddress
node, which may be different, for example on x86-64 where MVT::i32
is used when the address is being fit into the 32-bit displacement
field.

llvm-svn: 57885
2008-10-21 03:38:42 +00:00
Dan Gohman
281881b8e2 Optimized FCMP_OEQ and FCMP_UNE for x86.
Where previously LLVM might emit code like this:

        ucomisd %xmm1, %xmm0
        setne   %al
        setp    %cl
        orb     %al, %cl
        jne     .LBB4_2

it now emits this:

        ucomisd %xmm1, %xmm0
        jne     .LBB4_2
        jp      .LBB4_2

It has fewer instructions and uses fewer registers, but it does
have more branches. And in the case that this code is followed by
a non-fallthrough edge, it may be followed by a jmp instruction,
resulting in three branch instructions in sequence. Some effort
is made to avoid this situation.

To achieve this, X86ISelLowering.cpp now recognizes FCMP_OEQ and
FCMP_UNE in lowered form, and replace them with code that emits
two branches, except in the case where it would require converting
a fall-through edge to an explicit branch.

Also, X86InstrInfo.cpp's branch analysis and transform code now
knows now to handle blocks with multiple conditional branches. It
uses loops instead of having fixed checks for up to two
instructions. It can now analyze and transform code generated
from FCMP_OEQ and FCMP_UNE.

llvm-svn: 57873
2008-10-21 03:29:32 +00:00
Dan Gohman
d692070372 When the coalescer is doing rematerializing, have it remove
the copy instruction from the instruction list before asking the
target to create the new instruction. This gets the old instruction
out of the way so that it doesn't interfere with the target's
rematerialization code. In the case of x86, this helps it find
more cases where EFLAGS is not live.

Also, in the X86InstrInfo.cpp, teach isSafeToClobberEFLAGS to check
to see if it reached the end of the block after scanning each
instruction, instead of just before. This lets it notice when the
end of the block is only two instructions away, without doing any
additional scanning.

These changes allow rematerialization to clobber EFLAGS in more
cases, for example using xor instead of mov to set the return value
to zero in the included testcase.

llvm-svn: 57872
2008-10-21 03:24:31 +00:00
Dan Gohman
d9b79484e0 Make the NaN test come second, heuristically assuming
that NaNs are less common.

llvm-svn: 57871
2008-10-21 03:12:54 +00:00