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* [DAG] Don't pull the binary operation though the shift if the operands have ↵Juergen Ributzka2014-02-061-2/+9
| | | | | | | | | | | | opaque constants. During DAGCombine visitShiftByConstant assumes that certain binary operations with only constant operands can always be folded successfully. This is no longer true when the constant is opaque. This commit fixes visitShiftByConstant by not performing the optimization for opaque constants. Otherwise we would end up in an infinite DAGCombine loop. llvm-svn: 200900
* This patch teaches the DAGCombiner how to fold insert_subvector nodesManman Ren2014-01-311-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | when the input is a concat_vectors and the insert replaces one of the concat halves: Lower half: fold (insert_subvector (concat_vectors X, Y), Z) -> (concat_vectors Z, Y) Upper half: fold (insert_subvector (concat_vectors X, Y), Z) -> (concat_vectors X, Z) This can be seen with the following IR: define <8 x float> @lower_half(<4 x float> %v1, <4 x float> %v2, <4 x float> %v3) { %1 = shufflevector <4 x float> %v1, <4 x float> %v2, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7> %2 = tail call <8 x float> @llvm.x86.avx.vinsertf128.ps.256(<8 x float> %1, <4 x float> %v3, i8 0) The vinsertf128 intrinsic is converted into an insert_subvector node in SelectionDAGBuilder.cpp. Using AVX, without the patch this generates two vinsertf128 instructions: vinsertf128 $1, %xmm1, %ymm0, %ymm0 vinsertf128 $0, %xmm2, %ymm0, %ymm0 With the patch this is optimized into: vinsertf128 $1, %xmm1, %ymm2, %ymm0 Patch by Robert Lougher. llvm-svn: 200506
* DAGCombine should not produce ISD::OR nodes after operation legalization if ↵Owen Anderson2014-01-311-2/+4
| | | | | | they're not legal. llvm-svn: 200503
* [DAGCombiner] Avoid introducing an illegal build_vector when folding a ↵Andrea Di Biagio2014-01-281-9/+15
| | | | | | | | | | | | | | | | | sign_extend. Make sure that we don't introduce illegal build_vector dag nodes when trying to fold a sign_extend of a build_vector. This fixes a regression introduced by r200234. Added test CodeGen/X86/fold-vector-sext-crash.ll to verify that llc no longer crashes with an assertion failure due to an illegal build_vector of type MVT::v4i64. Thanks to Ilia Filippov for spotting this regression and for providing a reproducible test case. llvm-svn: 200313
* Fix sext(setcc) -> select_cc using wrong type for setcc.Matt Arsenault2014-01-271-10/+16
| | | | | | | | | | | | | | | | Also update the comment, since it actually produces a select (setcc) instead of select_cc. It was checking and using the setcc result type for the type of the sext, instead of the type of the compared items. In my problem case, the sext was to i32 and was used as the setcc type, but the expected type was i64. No test since I haven't been able to hit the problem with this on any in-tree targets. llvm-svn: 200249
* [DAGCombiner] Teach how to fold sext/aext/zext of constant build vectors.Andrea Di Biagio2014-01-271-9/+64
| | | | | | | | | | | | | This patch teaches the DAGCombiner how to fold a sext/aext/zext dag node when the operand in input is a build vector of constants (or UNDEFs). The inability to fold a sext/zext of a constant build_vector was the root cause of some pcg bugs affecting vselect expansion on x86-64 with AVX support. Before this change, the DAGCombiner only knew how to fold a sext/zext/aext of a ConstantSDNode. llvm-svn: 200234
* Fix for PR18102.Stepan Dyatkovskiy2014-01-271-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issue outcomes from DAGCombiner::MergeConsequtiveStores, more precisely from mem-ops sequence sorting. Consider, how MergeConsequtiveStores works for next example: store i8 1, a[0] store i8 2, a[1] store i8 3, a[1] ; a[1] again. return ; DAG starts here 1. Method will collect all the 3 stores. 2. It sorts them by distance from the base pointer (farthest with highest index). 3. It takes first consecutive non-overlapping stores and (if possible) replaces them with a single store instruction. The point is, we can't determine here which 'store' instruction would be the second after sorting ('store 2' or 'store 3'). It happens that 'store 3' would be the second, and 'store 2' would be the third. So after merging we have the next result: store i16 (1 | 3 << 8), base ; is a[0] but bit-casted to i16 store i8 2, a[1] So actually we swapped 'store 3' and 'store 2' and got wrong contents in a[1]. Fix: In sort routine just also take into account mem-op sequence number. llvm-svn: 200201
* Disable the use of TBAA when using AA in CodeGenHal Finkel2014-01-251-2/+14
| | | | | | | | | | | | | | | | | There are currently two issues, of which I currently know, that prevent TBAA from being correctly usable in CodeGen: 1. Stack coloring does not update TBAA when merging allocas. This is easy enough to fix, but is not the largest problem. 2. CGP inserts ptrtoint/inttoptr pairs when sinking address computations. Because BasicAA does not handle inttoptr, we'll often miss basic type punning idioms that we need to catch so we don't miscompile real-world code (like LLVM). I don't yet have a small test case for this, but this fixes self hosting a non-asserts build of LLVM on PPC64 when using -enable-aa-sched-mi and -misched=shuffle. llvm-svn: 200093
* Add combiner-aa-only-func (debug only)Hal Finkel2014-01-251-0/+22
| | | | | | | | | This option (which is !NDEBUG only) allows restricting the use of alias analysis in DAGCombiner to a specific function. This has proved extremely valuable to isolating bugs related to this feature, and mirrors the misched-only-func option provided by the new instruction scheduler. llvm-svn: 200088
* Improve descriptions of combiner-alias-analysis and ↵Hal Finkel2014-01-251-2/+2
| | | | | | combiner-global-alias-analysis llvm-svn: 200087
* Revert "Revert "Add Constant Hoisting Pass" (r200034)"Juergen Ributzka2014-01-251-3/+6
| | | | | | | This reverts commit r200058 and adds the using directive for ARMTargetTransformInfo to silence two g++ overload warnings. llvm-svn: 200062
* Revert "Add Constant Hoisting Pass" (r200034)Hans Wennborg2014-01-251-6/+3
| | | | | | | | | | | | | | | This commit caused -Woverloaded-virtual warnings. The two new TargetTransformInfo::getIntImmCost functions were only added to the superclass, and to the X86 subclass. The other targets were not updated, and the warning highlighted this by pointing out that e.g. ARMTTI::getIntImmCost was hiding the two new getIntImmCost variants. We could pacify the warning by adding "using TargetTransformInfo::getIntImmCost" to the various subclasses, or turning it off, but I suspect that it's wrong to leave the functions unimplemnted in those targets. The default implementations return TCC_Free, which I don't think is right e.g. for ARM. llvm-svn: 200058
* Add Constant Hoisting PassJuergen Ributzka2014-01-241-3/+6
| | | | | | | | Retry commit r200022 with a fix for the build bot errors. Constant expressions have (unlike instructions) module scope use lists and therefore may have users in different functions. The fix is to simply ignore these out-of-function uses. llvm-svn: 200034
* Fix DAGCombiner::GatherAllAliases to account for non-chain dependenciesHal Finkel2014-01-241-1/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DAGCombiner::GatherAllAliases, which is only used when AA used is enabled during DAGCombine, had a fundamentally incorrect assumption for which this change compensates. GatherAllAliases, which is used to find aliasing predecessor chain nodes (so that a better chain can be selected for a load or store to enable subsequent optimizations) assumed that walking up the chain would always catch all possibly-aliasing loads and stores. This is not true: To really find all aliases, we also need to search for aliases through the value operand of a store, etc. Consider the following situation: Token1 = ... L1 = load Token1, %52 S1 = store Token1, L1, %51 L2 = load Token1, %52+8 S2 = store Token1, L2, %51+8 Token2 = Token(S1, S2) L3 = load Token2, %53 S3 = store Token2, L3, %52 L4 = load Token2, %53+8 S4 = store Token2, L4, %52+8 If we search for aliases of S3 (which loads address %52), and we look only through the chain, then we'll miss the trivial dependence on L1 (which loads from %52). We then might change all loads and stores to use Token1 as their chain operand, which could result in copying %53 into %52 before copying %52 into %51 (which should happen first). The problem is, however, that searching for such data dependencies can become expensive, and the cost is not directly related to the chain depth. Instead, we'll rule out such configurations by insisting that we've visited all chain users (except for users of the original chain, which is not necessary). When doing this, we need to look through nodes we don't care about (otherwise, things like register copies will interfere with trivial use cases). Unfortunately, I don't have a small test case for this problem. Creating the underlying situation is not hard (a pair of memcpys will do it), but arranging for the default instruction schedule to be incorrect is very fragile. This unbreaks self hosting on PPC64 when using -mllvm -combiner-global-alias-analysis -mllvm -combiner-alias-analysis. llvm-svn: 200033
* Revert "Add Constant Hoisting Pass"Juergen Ributzka2014-01-241-6/+3
| | | | | | This reverts commit r200022 to unbreak the build bots. llvm-svn: 200024
* Restrict FindBetterChain DAG combines to unindexed nodesHal Finkel2014-01-241-2/+2
| | | | | | | | | | | | These transformations obviously won't work for indexed (pre/post-inc) loads and stores. In practice, I'm not sure there is any benefit to enabling them for indexed nodes because other transformations that these might enable likely also won't handle indexed nodes. I don't have an in-tree test case that hits this problem, but an upcoming bug fix will make it much more likely. llvm-svn: 200023
* Add Constant Hoisting PassJuergen Ributzka2014-01-241-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This pass identifies expensive constants to hoist and coalesces them to better prepare it for SelectionDAG-based code generation. This works around the limitations of the basic-block-at-a-time approach. First it scans all instructions for integer constants and calculates its cost. If the constant can be folded into the instruction (the cost is TCC_Free) or the cost is just a simple operation (TCC_BASIC), then we don't consider it expensive and leave it alone. This is the default behavior and the default implementation of getIntImmCost will always return TCC_Free. If the cost is more than TCC_BASIC, then the integer constant can't be folded into the instruction and it might be beneficial to hoist the constant. Similar constants are coalesced to reduce register pressure and materialization code. When a constant is hoisted, it is also hidden behind a bitcast to force it to be live-out of the basic block. Otherwise the constant would be just duplicated and each basic block would have its own copy in the SelectionDAG. The SelectionDAG recognizes such constants as opaque and doesn't perform certain transformations on them, which would create a new expensive constant. This optimization is only applied to integer constants in instructions and simple (this means not nested) constant cast experessions. For example: %0 = load i64* inttoptr (i64 big_constant to i64*) Reviewed by Eric llvm-svn: 200022
* Fix known typosAlp Toker2014-01-241-3/+3
| | | | | | | Sweep the codebase for common typos. Includes some changes to visible function names that were misspelt. llvm-svn: 200018
* AVX512: combining setcc and zext is wrong on AVX512Elena Demikhovsky2014-01-221-1/+4
| | | | | | because vector compare instruction puts result in mask register. llvm-svn: 199798
* Allow SMUL_LOHI and UMUL_LOHI to be narrow to MUL on targets where MUL is ↵Owen Anderson2014-01-201-1/+1
| | | | | | Custom rather than Legal. Even if the target is doing some kind of expansion for MUL, it's pretty much guaranteed to be more efficent than whatever it does for SMUL_LOHI or UMUL_LOHI! llvm-svn: 199678
* [DAGCombiner] Fix a wrong check in method SimplifyVBinOp.Andrea Di Biagio2014-01-151-2/+2
| | | | | | | | | | | | | | | | | | | This fixes a regression intruced by r199135. Revision 199135 tried to simplify part of the logic in method DAGCombiner::SimplifyVBinOp introducing calls to method BuildVectorSDNode::isConstant(). However, that revision wrongly changed the check performed by method SimplifyVBinOp to identify dag nodes that can be folded. Before revision 199135, that method only tried to simplify vector binary operations if both operands were build_vector of Constant/ConstantFP/Undef only. After revision 199135, method SimplifyVBinop tried to simplify also vector binary operations with only one constant operand. This fixes the problem restoring the old behavior of SimplifyVBinOp. llvm-svn: 199328
* [DAG] Refactor ReassociateOps - no functional change intended.Juergen Ributzka2014-01-131-73/+44
| | | | llvm-svn: 199146
* [DAG] Teach DAG to also reassociate vector operationsJuergen Ributzka2014-01-131-16/+51
| | | | | | | | | | This commit teaches DAG to reassociate vector ops, which in turn enables constant folding of vector op chains that appear later on during custom lowering and DAG combine. Reviewed by Andrea Di Biagio llvm-svn: 199135
* Handle masked rotate amountsRichard Sandiford2014-01-091-16/+72
| | | | | | | | | | | | | | At the moment we expect rotates to have the form: (or (shl X, Y), (shr X, Z)) where Y == bitsize(X) - Z or Z == bitsize(X) - Y. This form means that the (or ...) is undefined for Y == 0 or Z == 0. This undefinedness can be avoided by using Y == (C * bitsize(X) - Z) & (bitsize(X) - 1) or Z == (C * bitsize(X) - Y) & (bitsize(X) - 1) for any integer C (including 0, the most natural choice). llvm-svn: 198861
* Match the InstCombine form of rotates by X+CRichard Sandiford2014-01-091-12/+39
| | | | | | | | | | | | | | | | | InstCombine converts (sub 32, (add X, C)) into (sub 32-C, X), so a rotate left of a 32-bit Y by X+C could appear as either: (or (shl Y, (add X, C)), (shr Y, (sub 32, (add X, C)))) without InstCombine or: (or (shl Y, (add X, C)), (shr Y, (sub 32-C, X))) with it. We already matched the first form. This patch handles the second too. llvm-svn: 198860
* Teach the DAGCombiner how to fold 'vselect' dag nodes accordingAndrea Di Biagio2014-01-081-0/+7
| | | | | | | | to the following two rules: 1) fold (vselect (build_vector AllOnes), A, B) -> A 2) fold (vselect (build_vector AllZeros), A, B) -> B llvm-svn: 198777
* [DAGCombiner] Factor duplicated rotate code into a separate functionRichard Sandiford2014-01-081-66/+70
| | | | | | No functional change intended. llvm-svn: 198768
* [AArch64 NEON] Fix invalid constant used in vselect condition.Kevin Qin2014-01-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | There is a wrong assumption that the vector element type and the type of each ConstantSDNode in the build_vector were the same. However, when promoting the integer operand of a legally typed build_vector, the operand type and the vector element type do not need to be the same (See method 'DAGTypeLegalizer::PromoteIntOp_BUILD_VECTOR' in LegalizeIntegerTypes.cpp). in AArch64 backend, the following dag sequence: C0: i1 = Constant<0> C1: i1 = Constant<-1> V: v8i1 = BUILD_VECTOR C1, C1, C0, C0, C0, C0, C0, C0 is type-legalized into: NewC0: i32 = Constant<0> NewC1: i32 = Constant<1> V: v8i8 = BUILD_VECTOR NewC1, NewC1, NewC0, NewC0, NewC0, NewC0, NewC0, NewC0 Forcing a getZeroExtend to VTBits to ensure that the new constant is correctly. llvm-svn: 198582
* Fix a bug in DAGcombiner about zero-extend after setcc.Kevin Qin2013-12-301-1/+2
| | | | | | | | | | For AArch64 backend, if DAGCombiner see "sext(setcc)", it will combine them together to a single setcc with extended value type. Then if it see "zext(setcc)", it assumes setcc is Vxi1, and try to create "(and (vsetcc), (1, 1, ...)". While setcc isn't Vxi1, DAGcombiner will create wrong node and get wrong code emitted. llvm-svn: 198190
* Teach DAGCombiner how to fold a SIGN_EXTEND_INREG of a BUILD_VECTOR ofAndrea Di Biagio2013-12-271-0/+23
| | | | | | | | | | | | | | | | | | | | ConstantSDNodes (or UNDEFs) into a simple BUILD_VECTOR. For example, given the following sequence of dag nodes: i32 C = Constant<1> v4i32 V = BUILD_VECTOR C, C, C, C v4i32 Result = SIGN_EXTEND_INREG V, ValueType:v4i1 The SIGN_EXTEND_INREG node can be folded into a build_vector since the vector in input is a BUILD_VECTOR of constants. The optimized sequence is: i32 C = Constant<-1> v4i32 Result = BUILD_VECTOR C, C, C, C llvm-svn: 198084
* Extend (truncate (load)) foldingRichard Sandiford2013-12-111-0/+14
| | | | | | | | | DAGCombiner could fold (truncate (load)) -> smaller load if the original load was the width of the truncation result or wider. This patch extends it to handle cases where the original load was narrower (and so the extension type stays the same). llvm-svn: 197030
* Fix PR18162 - Incorrect assertion assumed that the SDValue resno is zero.Nadav Rotem2013-12-101-1/+1
| | | | llvm-svn: 196858
* Correct word hyphenationsAlp Toker2013-12-051-2/+2
| | | | | | | This patch tries to avoid unrelated changes other than fixing a few hyphen-related ambiguities and contractions in nearby lines. llvm-svn: 196471
* Unrevert r195599 with testcase fix.Bill Wendling2013-11-251-0/+5
| | | | | | | I'm not sure how it was checking for the wrong values... PR18023. llvm-svn: 195670
* Revert r195599 as it broke the builds.Amara Emerson2013-11-251-5/+0
| | | | llvm-svn: 195636
* Fixed tryFoldToZero() for vector types that need expansion.Daniel Sanders2013-11-251-13/+2
| | | | | | | | | | | | | | | | | | | | | | Summary: Moved the requirement for SelectionDAG::getConstant() to return legally typed nodes slightly earlier. There were two optional DAGCombine passes that were missed out and were required to produce type-legal DAGs. Simplified a code-path in tryFoldToZero() to use SelectionDAG::getConstant(). This provides support for both promoted and expanded vector types whereas the previous code only supported promoted vector types. Fixes a "Type for zero vector elements is not legal" assertion detected by an llvm-stress generated test. Reviewers: resistor CC: llvm-commits Differential Revision: http://llvm-reviews.chandlerc.com/D2251 llvm-svn: 195635
* Don't look past volatile loads.Bill Wendling2013-11-251-0/+5
| | | | | | | A volatile load should block us from trying to coalesce stores. PR18023 llvm-svn: 195599
* Split SETCC if VSELECT requires splitting too.Tom Stellard2013-11-221-17/+39
| | | | | | | | | | | | | This patch is a rewrite of the original patch commited in r194542. Instead of relying on the type legalizer to do the splitting for us, we now peform the splitting ourselves in the DAG combiner. This is necessary for the case where the vector mask is a legal type after promotion and still wouldn't require splitting. Patch by: Juergen Ributzka NOTE: This is a candidate for the 3.4 branch. llvm-svn: 195397
* DAGCombiner: Partially revert r192795, getNOT was fixed not to create ↵Benjamin Kramer2013-11-171-1/+1
| | | | | | illegal constants. llvm-svn: 194959
* Add target hook to prevent folding some bitcasted loads.Matt Arsenault2013-11-151-1/+2
| | | | | | | | | | | | | This is to avoid this transformation in some cases: fold (conv (load x)) -> (load (conv*)x) On architectures that don't natively support some vector loads efficiently casting the load to a smaller vector of larger types and loading is more efficient. Patch by Micah Villmow. llvm-svn: 194783
* SelectionDAG: Teach the legalizer to split SETCC if VSELECT needs splitting too.Juergen Ributzka2013-11-131-0/+23
| | | | | | | | | | | | | | | | | | | | | | This patch reapplies r193676 with an additional fix for the Hexagon backend. The SystemZ backend has already been fixed by r194148. The Type Legalizer recognizes that VSELECT needs to be split, because the type is to wide for the given target. The same does not always apply to SETCC, because less space is required to encode the result of a comparison. As a result VSELECT is split and SETCC is unrolled into scalar comparisons. This commit fixes the issue by checking for VSELECT-SETCC patterns in the DAG Combiner. If a matching pattern is found, then the result mask of SETCC is promoted to the expected vector mask type for the given target. Now the type legalizer will split both VSELECT and SETCC. This allows the following X86 DAG Combine code to sucessfully detect the MIN/MAX pattern. This fixes PR16695, PR17002, and <rdar://problem/14594431>. Reviewed by Nadav llvm-svn: 194542
* Vector forms of SHL, SRA, and SRL can be constant folded using ↵Daniel Sanders2013-11-111-0/+18
| | | | | | | | | | | | | | SimplifyVBinOp too Reviewers: dsanders Reviewed By: dsanders CC: llvm-commits, nadav Differential Revision: http://llvm-reviews.chandlerc.com/D1958 llvm-svn: 194393
* Revert "SelectionDAG: Teach the legalizer to split SETCC if VSELECT needs ↵Juergen Ributzka2013-10-301-22/+0
| | | | | | | | splitting too." Now Hexagon and SystemZ are not happy with it :-( llvm-svn: 193677
* SelectionDAG: Teach the legalizer to split SETCC if VSELECT needs splitting too.Juergen Ributzka2013-10-301-0/+22
| | | | | | | | | | | | | | | | | | | | The Type Legalizer recognizes that VSELECT needs to be split, because the type is to wide for the given target. The same does not always apply to SETCC, because less space is required to encode the result of a comparison. As a result VSELECT is split and SETCC is unrolled into scalar comparisons. This commit fixes the issue by checking for VSELECT-SETCC patterns in the DAG Combiner. If a matching pattern is found, then the result mask of SETCC is promoted to the expected vector mask type for the given target. This mask has usually the same size as the VSELECT return type (except for Intel KNL). Now the type legalizer will split both VSELECT and SETCC. This allows the following X86 DAG Combine code to sucessfully detect the MIN/MAX pattern. This fixes PR16695, PR17002, and <rdar://problem/14594431>. Reviewed by Nadav llvm-svn: 193676
* [DAGCombiner] Respect volatility when checking for aliasesRichard Sandiford2013-10-281-18/+25
| | | | | | | | Making useAA() default to true for SystemZ showed that the combiner alias analysis wasn't handling volatile accesses. This hit many of the SystemZ tests, but I arbitrarily picked one for the purpose of this patch. llvm-svn: 193518
* Keep TBAA info when rewriting SelectionDAG loads and storesRichard Sandiford2013-10-281-99/+56
| | | | | | | | | | | | | | | | | Most SelectionDAG code drops the TBAA info when creating a new form of a load and store (e.g. during legalization, or when converting a plain load to an extending one). This patch tries to catch all cases where the TBAA information can legitimately be carried over. The patch adds alternative forms of getLoad() and getExtLoad() that take a MachineMemOperand instead of individual fields. (The corresponding getTruncStore() already exists.) The idea is to use the MachineMemOperand forms when all fields are carried over (size, pointer info, isVolatile, isNonTemporal, alignment and TBAA info). If some adjustment is being made, e.g. to narrow the load, then we still pass the individual fields but also pass the TBAA info. llvm-svn: 193517
* Optimize concat_vectors(X, undef) -> scalar_to_vector(X).Nadav Rotem2013-10-251-1/+28
| | | | | | | This optimization is not SSE specific so I am moving it to DAGco. The new scalar_to_vector dag node exposed a missing pattern in the AArch64 target that I needed to add. llvm-svn: 193393
* Fix edge condition in DAGCombiner to improve codegen of shift sequences.Andrea Di Biagio2013-10-171-0/+1
| | | | | | | | | | | | When canonicalizing dags according to the rule (shl (zext (shr X, c1) ), c1) ==> (zext (shl (shr X, c1), c1)) remember to add the new shl dag to the DAGCombiner worklist of nodes. If we don't explicitly add it to the worklist of nodes to visit, we may not trigger later on the rule that folds the shift left + logical shift right into a AND instruction with bitmask. llvm-svn: 192883
* [projects/test-suite] White space and long line fixes.Jack Carter2013-10-171-15/+21
| | | | | | No functionality changes. llvm-svn: 192863
* DAGCombiner: Don't fold xor into not if getNOT would introduce an illegal ↵Benjamin Kramer2013-10-161-1/+1
| | | | | | | | | | | constant. This happens e.g. with <2 x i64> -1 on x86_32. It cannot be generated directly because i64 is illegal. It would be nice if getNOT would handle this transparently, but I don't see a way to generate a legal constant there right now. Fixes PR17487. llvm-svn: 192795
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