Commit Graph

378 Commits

Author SHA1 Message Date
Bill Wendling
6c923bb8d9 Merge the contents from exception-handling-rewrite to the mainline.
This adds the new instructions 'landingpad' and 'resume'.

llvm-svn: 136253
2011-07-27 20:18:04 +00:00
Jeffrey Yasskin
6381c0100b Explicitly cast narrowing conversions inside {}s that will become errors in
C++0x.

llvm-svn: 136211
2011-07-27 06:22:51 +00:00
Eli Friedman
fee02c6c13 Initial implementation of 'fence' instruction, the new C++0x-style replacement for llvm.memory.barrier.
This is just a LangRef entry and reading/writing/memory representation; optimizer+codegen support coming soon.

llvm-svn: 136009
2011-07-25 23:16:38 +00:00
Chris Lattner
229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Eric Christopher
92464be28c Check register class matching instead of width of type matching
when determining validity of matching constraint. Allow i1
types access to the GR8 reg class for x86.

Fixes PR10352 and rdar://9777108

llvm-svn: 135180
2011-07-14 20:13:52 +00:00
Benjamin Kramer
15cd5a3f12 Don't emit a bit test if there is only one case the test can yield false. A simple SETNE is sufficient.
llvm-svn: 135126
2011-07-14 01:38:42 +00:00
Jay Foad
57aa636794 Convert InsertValueInst and ExtractValueInst APIs to use ArrayRef.
llvm-svn: 135040
2011-07-13 10:26:04 +00:00
Cameron Zwarich
f03fa189ca Add an intrinsic and codegen support for fused multiply-accumulate. The intent
is to use this for architectures that have a native FMA instruction.

llvm-svn: 134742
2011-07-08 21:39:21 +00:00
Benjamin Kramer
2bb8b26aa8 Apparently we can't expect a BinaryOperator here.
Should fix llvm-gcc selfhost.

llvm-svn: 134699
2011-07-08 12:08:24 +00:00
Benjamin Kramer
9960a25006 Emit a more efficient magic number multiplication for exact sdivs.
We have to do this in DAGBuilder instead of DAGCombiner, because the exact bit is lost after building.

  struct foo { char x[24]; };
  long bar(struct foo *a, struct foo *b) { return a-b; }
is now compiled into
  movl	4(%esp), %eax
  subl	8(%esp), %eax
  sarl	$3, %eax
  imull	$-1431655765, %eax, %eax
instead of
  movl	4(%esp), %eax
  subl	8(%esp), %eax
  movl	$715827883, %ecx
  imull	%ecx
  movl	%edx, %eax
  shrl	$31, %eax
  sarl	$2, %edx
  addl	%eax, %edx
  movl	%edx, %eax

llvm-svn: 134695
2011-07-08 10:31:30 +00:00
Jakub Staszak
3f158fdf6e Introduce "expect" intrinsic instructions.
llvm-svn: 134516
2011-07-06 18:22:43 +00:00
Eric Christopher
f81292ba3b Remove getRegClassForInlineAsmConstraint and all dependencies.
Fixes rdar://9643582

llvm-svn: 134123
2011-06-30 01:20:03 +00:00
Jakob Stoklund Olesen
537a302d1a Distinguish early clobber output operands from clobbered registers.
Both become <earlyclobber> defs on the INLINEASM MachineInstr, but we
now use two different asm operand kinds.

The new Kind_Clobber is treated identically to the old
Kind_RegDefEarlyClobber for now, but x87 floating point stack inline
assembly does care about the difference.

This will pop a register off the stack:

  asm("fstp %st" : : "t"(x) : "st");

While this will pop the input and push an output:

  asm("fst %st" : "=&t"(r) : "t"(x));

We need to know if ST0 was a clobber or an output operand, and we can't
depend on <dead> flags for that.

llvm-svn: 133902
2011-06-27 04:08:33 +00:00
Nadav Rotem
36896bfd0c When promoting the vector elements in CopyToParts, use vector trunc
instead of scalarizing, and doing an element-by-element truncat.

llvm-svn: 133382
2011-06-19 08:49:38 +00:00
Jakub Staszak
12a43bdde5 Introduce MachineBranchProbabilityInfo class, which has similar API to
BranchProbabilityInfo (expect setEdgeWeight which is not available here).
Branch Weights are kept in MachineBasicBlocks. To turn off this analysis
set -use-mbpi=false.

llvm-svn: 133184
2011-06-16 20:22:37 +00:00
Jakob Stoklund Olesen
1f641d577e Add TargetRegisterInfo::getRawAllocationOrder().
This virtual function will replace allocation_order_begin/end as the one
to override when implementing custom allocation orders. It is simpler to
have one function return an ArrayRef than having two virtual functions
computing different ends of the same array.

Use getRawAllocationOrder() in place of allocation_order_begin() where
it makes sense, but leave some clients that look like they really want
the filtered allocation orders from RegisterClassInfo.

llvm-svn: 133170
2011-06-16 17:42:25 +00:00
Bruno Cardoso Lopes
dc9ff3a4b1 Add one more argument to the prefetch intrinsic to indicate whether it's a data
or instruction cache access. Update the targets to match it and also teach
autoupgrade.

llvm-svn: 132976
2011-06-14 04:58:37 +00:00
Nadav Rotem
083837e729 Improve the generated code by getCopyFromPartsVector for promoted integer types.
Instead of scalarizing, and doing an element-by-element truncat, use vector
truncate.
Add support for scalarization of vectors:  i8 -> <1 x i1> (from Duncan's
testcase).

llvm-svn: 132892
2011-06-12 14:49:38 +00:00
Eric Christopher
0713a9d8fc Add a parameter to CCState so that it can access the MachineFunction.
No functional change.

Part of PR6965

llvm-svn: 132763
2011-06-08 23:55:35 +00:00
Nadav Rotem
06bd6d304e TypeLegalizer: Add support for passing of vector-promoted types in registers (copyFromParts/copyToParts).
llvm-svn: 132649
2011-06-04 20:58:08 +00:00
Eric Christopher
fbff0e4f26 Add a TODO about memory operands.
llvm-svn: 132559
2011-06-03 17:21:23 +00:00
Eric Christopher
de9399bf76 Have LowerOperandForConstraint handle multiple character constraints.
Part of rdar://9119939

llvm-svn: 132510
2011-06-02 23:16:42 +00:00
Eric Christopher
690030c116 Allow bitcasts between valid types of the same size and vector
types if the vector type is legal.

Fixes rdar://9306086

llvm-svn: 132420
2011-06-01 19:55:10 +00:00
Devang Patel
7992883811 Preserve debug info during iSel by keeping DanglingDebugInfoMap live until end of function.
Patch by Micah Villmow

llvm-svn: 131908
2011-05-23 17:44:13 +00:00
Chris Lattner
68254fcbca Eliminate some temporary variables, and don't call getByValTypeAlignment
when we're just going to throw the result away.  No functionality change.

llvm-svn: 131880
2011-05-22 23:23:02 +00:00
Devang Patel
8e60ff11db Preserve debug info for unused zero extended boolean argument.
Radar 9422775.

llvm-svn: 131422
2011-05-16 21:24:05 +00:00
Rafael Espindola
e53b7d1a11 Make codegen able to handle values of empty types. This is one way
to fix PR9900. I will keep it open until sable is able to comment on it.

llvm-svn: 131294
2011-05-13 15:18:06 +00:00
Bill Wendling
50117f8186 Give the 'eh.sjlj.dispatchsetup' intrinsic call the value coming from the setjmp
intrinsic call. This prevents it from being reordered so that it appears
*before* the setjmp intrinsic (thus making it completely useless).
<rdar://problem/9409683>

llvm-svn: 131174
2011-05-11 01:11:55 +00:00
Eli Friedman
768de0a0f8 Disable my little CopyToReg argument hack with fast-isel. rdar://problem/9413587 .
llvm-svn: 131156
2011-05-10 21:50:58 +00:00
Eric Christopher
4480428474 Look through struct wrapped types for inline asm statments.
Patch by Evan Cheng.

llvm-svn: 131093
2011-05-09 20:04:43 +00:00
Evan Cheng
d26fc5e013 80 col violations.
llvm-svn: 131015
2011-05-06 20:52:23 +00:00
Eli Friedman
441a01a2b8 Avoid extra vreg copies for arguments passed in registers. Specifically, this can make MachineCSE more effective in some cases (especially in small functions). PR8361 / part of rdar://problem/8259436 .
llvm-svn: 130928
2011-05-05 16:53:34 +00:00
Devang Patel
734f2218ac A dbg.declare may not be in entry block, even if it is referring to an incoming argument. However, It is appropriate to emit DBG_VALUE referring to this incoming argument in entry block in MachineFunction.
llvm-svn: 130129
2011-04-25 16:33:52 +00:00
Chris Lattner
0ab5e2cded Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
2011-04-15 05:18:47 +00:00
Chris Lattner
cfe5aa65d2 Avoid excess precision issues that lead to generating host-compiler-specific code.
Switch lowering probably shouldn't be using FP for this.  This resolves PR9581.

llvm-svn: 129199
2011-04-09 06:57:13 +00:00
Evan Cheng
74d92c1924 Change -arm-trap-func= into a non-arm specific option. Now Intrinsic::trap is lowered into a call to the specified trap function at sdisel time.
llvm-svn: 129152
2011-04-08 21:37:21 +00:00
Bill Wendling
dd4dcd549b Revamp the SjLj "dispatch setup" intrinsic.
It needed to be moved closer to the setjmp statement, because the code directly
after the setjmp needs to know about values that are on the stack. Also, the
'bitcast' of the function context was causing a dead load. This wouldn't be too
horrible, except that at -O0 it wasn't optimized out, and because it wasn't
using the correct base pointer (if there is a VLA), it would try to access a
value from a garbage address.
<rdar://problem/9130540>

llvm-svn: 128873
2011-04-05 01:37:43 +00:00
Evan Cheng
8b1bca1998 Add comments.
llvm-svn: 128730
2011-04-01 19:57:01 +00:00
Evan Cheng
8d68ebd42a Assign node order numbers to results of call instruction lowering. This should improve src line debug info when sdisel is used. rdar://9199118
llvm-svn: 128728
2011-04-01 19:42:22 +00:00
Benjamin Kramer
355ce07425 Turn SelectionDAGBuilder::GetRegistersForValue into a local function.
It couldn't be used outside of the file because SDISelAsmOperandInfo
is local to SelectionDAGBuilder.cpp. Making it a static function avoids
a weird linkage dance.

llvm-svn: 128342
2011-03-26 16:35:10 +00:00
Cameron Zwarich
2ef0c69df1 Move more logic into getTypeForExtArgOrReturn.
llvm-svn: 127809
2011-03-17 14:53:37 +00:00
Cameron Zwarich
34e7b3f77e Rename getTypeForExtendedInteger() to getTypeForExtArgOrReturn().
llvm-svn: 127807
2011-03-17 14:21:56 +00:00
Cameron Zwarich
ac106273d4 The x86-64 ABI says that a bool is only guaranteed to be sign-extended to a byte
rather than an int. Thankfully, this only causes LLVM to miss optimizations, not
generate incorrect code.

This just fixes the zext at the return. We still insert an i32 ZextAssert when
reading a function's arguments, but it is followed by a truncate and another i8
ZextAssert so it is not optimized.

llvm-svn: 127766
2011-03-16 22:20:18 +00:00
Cameron Zwarich
d1ad9bc277 Don't recompute something that we already have in a local variable.
llvm-svn: 127764
2011-03-16 22:20:07 +00:00
Andrew Trick
710d5da306 Replace -dag-chain-limit flag with constant. It has survived a release cycle without being touched, so no longer needs to pollute the hidden-help text.
llvm-svn: 127468
2011-03-11 17:46:59 +00:00
Owen Anderson
b2c80da4ae Allow targets to specify a the type of the RHS of a shift parameterized on the type of the LHS.
llvm-svn: 126518
2011-02-25 21:41:48 +00:00
Jim Grosbach
14a07365cb Fix formatting of debug helper string.
llvm-svn: 126471
2011-02-25 03:59:03 +00:00
Cameron Zwarich
6470647383 Refactor the LiveOutInfo interface into a few methods on FunctionLoweringInfo
and make the actual map private.

llvm-svn: 126376
2011-02-24 10:00:08 +00:00
Cameron Zwarich
f8b22b3483 Roll out r126169 and r126170 in an attempt to fix the selfhost bot.
llvm-svn: 126185
2011-02-22 03:24:52 +00:00
Cameron Zwarich
800f85baf9 Merge information about the number of zero, one, and sign bits of live-out registers
at phis. This enables us to eliminate a lot of pointless zexts during the DAGCombine
phase. This fixes <rdar://problem/8760114>.

llvm-svn: 126170
2011-02-22 00:46:27 +00:00
Devang Patel
b7ae3ccb84 Do not lose debug info of an inlined function argument even if the argument is only used through GEPs.
This time with a fix that avoids using invalidated DenseMap iterator.

llvm-svn: 125984
2011-02-18 22:43:42 +00:00
Cameron Zwarich
0a1a36dc46 Roll out r125794 to help diagnose the llvm-gcc-i386-linux-selfhost failure.
llvm-svn: 125830
2011-02-18 04:58:10 +00:00
Devang Patel
f922a431ee Do not lose debug info of an inlined function argument even if the argument is only used through GEPs.
llvm-svn: 125794
2011-02-17 23:33:27 +00:00
Chris Lattner
69229316aa convert ConstantVector::get to use ArrayRef.
llvm-svn: 125537
2011-02-15 00:14:00 +00:00
Chris Lattner
34442e6ebf revert my ConstantVector patch, it seems to have made the llvm-gcc
builders unhappy.

llvm-svn: 125504
2011-02-14 18:15:46 +00:00
Chris Lattner
d9f5b88548 Switch ConstantVector::get to use ArrayRef instead of a pointer+size
idiom.  Change various clients to simplify their code.

llvm-svn: 125487
2011-02-14 07:55:32 +00:00
Chris Lattner
e95d195014 Revisit my fix for PR9028: the issue is that DAGCombine was
generating i8 shift amounts for things like i1024 types.  Add
an assert in getNode to prevent this from occuring in the future,
fix the buggy transformation, revert my previous patch, and
document this gotcha in ISDOpcodes.h

llvm-svn: 125465
2011-02-13 19:09:16 +00:00
Chris Lattner
d5f0b1148a when legalizing extremely wide shifts, make sure that
the shift amounts are in a suitably wide type so that
we don't generate out of range constant shift amounts.

This fixes PR9028.

llvm-svn: 125458
2011-02-13 09:10:56 +00:00
Chris Lattner
2a720d933a fix visitShift to properly zero extend the shift amount if the provided operand
is narrower than the shift register.  Doing an anyext provides undefined bits in
the top part of the register.

llvm-svn: 125457
2011-02-13 09:02:52 +00:00
Nick Lewycky
0af77fd45b Fix build with stdcxx by using llvm::next. Patch by Joerg Sonnenberger!
llvm-svn: 124472
2011-01-28 04:00:15 +00:00
Devang Patel
70f8e5962a Resolve DanglingDbgValue of PHI nodes where the use follows dbg.value intrinisic.
llvm-svn: 124203
2011-01-25 18:09:58 +00:00
Devang Patel
533479544b Speculatively revert r124138.
llvm-svn: 124142
2011-01-24 20:04:37 +00:00
Devang Patel
8cc5355c90 Resolve DanglingDbgValue of PHI nodes where the use follows dbg.value intrinisic.
llvm-svn: 124138
2011-01-24 19:24:37 +00:00
Anton Korobeynikov
2f93128109 Rename TargetFrameInfo into TargetFrameLowering. Also, put couple of FIXMEs and fixes here and there.
llvm-svn: 123170
2011-01-10 12:39:04 +00:00
Jakob Stoklund Olesen
2fb5b31578 Simplify a bunch of isVirtualRegister() and isPhysicalRegister() logic.
These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

llvm-svn: 123155
2011-01-10 02:58:51 +00:00
Jakob Stoklund Olesen
793d7b7626 Use an IndexedMap for LiveOutRegInfo to hide its dependence on TargetRegisterInfo::FirstVirtualRegister.
llvm-svn: 123096
2011-01-08 23:10:50 +00:00
Evan Cheng
6eb516dbea Do not model all INLINEASM instructions as having unmodelled side effects.
Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.

This allows memory instructions to be moved around INLINEASM instructions.

llvm-svn: 123044
2011-01-07 23:50:32 +00:00
Bob Wilson
8265d56638 Add ARM patterns to match EXTRACT_SUBVECTOR nodes.
Also fix an off-by-one in SelectionDAGBuilder that was preventing shuffle
vectors from being translated to EXTRACT_SUBVECTOR.
Patch by Tim Northover.

The test changes are needed to keep those spill-q tests from testing aligned
spills and restores.  If the only aligned stack objects are spill slots, we
no longer realign the stack frame.  Prior to this patch, an EXTRACT_SUBVECTOR
was legalized by loading from the stack, which created an aligned frame index.
Now, however, there is nothing except the spill slot in the stack frame, so
I added an aligned alloca.

llvm-svn: 122995
2011-01-07 04:59:04 +00:00
Evan Cheng
ac730dd2d1 Avoid zero extend bit test operands to pointer type if all the masks fit in
the original type of the switch statement key.
rdar://8781238

llvm-svn: 122935
2011-01-06 01:02:44 +00:00
Chris Lattner
3e5fbd74ed rename MVT::Flag to MVT::Glue. "Flag" is a terrible name for
something that just glues two nodes together, even if it is
sometimes used for flags.

llvm-svn: 122310
2010-12-21 02:38:05 +00:00
Chris Lattner
cb404360ca reduce indentation by using continue, no functionality change.
llvm-svn: 121662
2010-12-13 01:11:17 +00:00
Jay Foad
583abbc4df PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.

llvm-svn: 121120
2010-12-07 08:25:19 +00:00
Devang Patel
c24048a718 If dbg_declare() or dbg_value() is not lowered by isel then emit DEBUG message instead of creating DBG_VALUE for undefined value in reg0.
llvm-svn: 121059
2010-12-06 22:39:26 +00:00
Chris Lattner
ea41dfe385 add TLI support indicating that jumps are more expensive than logical operations
and use this to disable a specific optimization.  Patch by Micah Villmow!

llvm-svn: 120435
2010-11-30 18:12:52 +00:00
Wesley Peck
527da1b6e2 Renaming ISD::BIT_CONVERT to ISD::BITCAST to better reflect the LLVM IR concept.
llvm-svn: 119990
2010-11-23 03:31:01 +00:00
Benjamin Kramer
24656c9583 Implement the "if (X == 6 || X == 4)" -> "if ((X|2) == 6)" optimization.
This currently only catches the most basic case, a two-case switch, but can be
extended later.

llvm-svn: 119964
2010-11-22 09:45:38 +00:00
Andrew Trick
cf7fefb25c Removing the useless test that I added recently. It was meant as an example, but not complicated enough to merit another test.
llvm-svn: 119898
2010-11-20 07:26:51 +00:00
John Thompson
ddc7ce548c Bug 8621 fix - pointer cast stripped from inline asm constraint argument.
llvm-svn: 119590
2010-11-17 23:58:47 +00:00
Andrew Trick
6cbf6c1db5 typo (4th checkin for one fix)
llvm-svn: 118913
2010-11-12 18:36:03 +00:00
Andrew Trick
116efac780 Fixes PR8287: SD scheduling time. The fix is a failsafe that prevents
catastrophic compilation time in the event of unreasonable LLVM
IR. Code quality is a separate issue--someone upstream needs to do a
better job of reducing to llvm.memcpy. If the situation can be reproduced with
any supported frontend, then it will be a separate bug.

llvm-svn: 118904
2010-11-12 17:50:46 +00:00
Chris Lattner
64634c36dd tidy up.
llvm-svn: 118896
2010-11-12 17:24:29 +00:00
Dan Gohman
6cf9bb45ad Remove the memmove->memcpy optimization from CodeGen. MemCpyOpt does this.
llvm-svn: 118789
2010-11-11 16:24:49 +00:00
Duncan Sands
f5dda01f33 Inside the calling convention logic LocVT is always a simple
value type, so there is no point in passing it around using
an EVT.  Use the simpler MVT everywhere.  Rather than trying
to propagate this information maximally in all the code that
using the calling convention stuff, I chose to do a mainly
low impact change instead.

llvm-svn: 118167
2010-11-03 11:35:31 +00:00
Devang Patel
bc741405a7 If value map does not have register for an argument then try to find frame index before giving up.
llvm-svn: 118022
2010-11-02 17:19:03 +00:00
Devang Patel
94f2a2578c Use frameindex, if available, as a last resort to emit debug info for a parameter.
llvm-svn: 118020
2010-11-02 17:01:30 +00:00
John Thompson
e8360b7182 Inline asm multiple alternative constraints development phase 2 - improved basic logic, added initial platform support.
llvm-svn: 117667
2010-10-29 17:29:13 +00:00
Dale Johannesen
e660f4d072 Use a MemIntrinsicSDNode for ISD::PREFETCH, which touches
memory, so a MachineMemOperand is useful (not propagated
into the MachineInstr yet).  No functional change except
for dump output.

llvm-svn: 117413
2010-10-26 23:11:10 +00:00
Devang Patel
05561e8b7b Assign source ordering to nodes created for StoreInst.
llvm-svn: 117404
2010-10-26 22:14:52 +00:00
Michael J. Spencer
0e36e0340a X86: Base _fltused on the FunctionType of the called value instead of the potentially null "CalledFunction". Thanks Duncan!
This is needed for indirect calls.

llvm-svn: 117061
2010-10-21 20:49:23 +00:00
Michael J. Spencer
83ce5f181f CodeGen-Windows: Only emit _fltused if a VarArg function is called with floating point args.
This should be the minimum set of functions that could possibly need it.

llvm-svn: 116978
2010-10-21 00:08:21 +00:00
Dan Gohman
a94cc6dfe8 Make CodeGen TBAA-aware.
llvm-svn: 116890
2010-10-20 00:31:05 +00:00
Jim Grosbach
bbdc5d2ef9 Add a pre-dispatch SjLj EH hook on the unwind edge for targets to do any
setup they require. Use this for ARM/Darwin to rematerialize the base
pointer from the frame pointer when required. rdar://8564268

llvm-svn: 116879
2010-10-19 23:27:08 +00:00
Michael J. Spencer
5e683250ee X86-Windows: Emit an undefined global __fltused symbol when targeting Windows
if any floating point arguments are passed to an external function.

llvm-svn: 116665
2010-10-16 08:25:41 +00:00
Michael J. Spencer
d3ea25e66e Whitespace!
llvm-svn: 116664
2010-10-16 08:25:21 +00:00
Dan Gohman
aadc5596f1 ComputeLinearIndex doesn't need its TLI argument.
llvm-svn: 115792
2010-10-06 16:18:29 +00:00
Devang Patel
d3fe5fa5d1 Fix code gen crash reported in PR 8235. We still lose debug info for the unused argument here. This is a known limitation recorded debuginfo-tests/trunk/dbg-declare2.ll function 'f6' test case.
llvm-svn: 115323
2010-10-01 19:00:44 +00:00
Gabor Greif
47a3b8c30b typo
llvm-svn: 115310
2010-10-01 10:32:19 +00:00
Chris Lattner
f08bfdc29f fix typo
llvm-svn: 115300
2010-10-01 06:54:02 +00:00
Dale Johannesen
dd224d2333 Massive rewrite of MMX:
The x86_mmx type is used for MMX intrinsics, parameters and
return values where these use MMX registers, and is also
supported in load, store, and bitcast.

Only the above operations generate MMX instructions, and optimizations
do not operate on or produce MMX intrinsics. 

MMX-sized vectors <2 x i32> etc. are lowered to XMM or split into
smaller pieces.  Optimizations may occur on these forms and the
result casted back to x86_mmx, provided the result feeds into a
previous existing x86_mmx operation.

The point of all this is prevent optimizations from introducing
MMX operations, which is unsafe due to the EMMS problem.

llvm-svn: 115243
2010-09-30 23:57:10 +00:00
Jakob Stoklund Olesen
665aa6efcc When isel is emitting instructions for an x86 target without CMOV, the CFG is
edited during emission.

If the basic block ends in a switch that gets lowered to a jump table, any
phis at the default edge were getting updated wrong. The jump table data
structure keeps a pointer to the header blocks that wasn't getting updated
after the MBB is split.

This bug was exposed on 32-bit Linux when disabling critical edge splitting in
codegen prepare.

The fix is to uipdate stale MBB pointers whenever a block is split during
emission.

llvm-svn: 115191
2010-09-30 19:44:31 +00:00