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* [Constants] If we already have a ConstantInt*, prefer to use ↵Craig Topper2017-07-061-3/+3
| | | | | | | | isZero/isOne/isMinusOne instead of isNullValue/isOneValue/isAllOnesValue inherited from Constant. NFCI Going through the Constant methods requires redetermining that the Constant is a ConstantInt and then calling isZero/isOne/isMinusOne. llvm-svn: 307292
* [InstCombine] Change helper method to a file local static method. NFCCraig Topper2017-07-061-4/+5
| | | | llvm-svn: 307275
* [InstCombine] Clarify comment to mention other transform that it does. NFCCraig Topper2017-07-061-1/+2
| | | | llvm-svn: 307274
* [InstCombine] Add single use checks to SimplifyBSwap to ensure we are really ↵Craig Topper2017-07-061-4/+9
| | | | | | | | | | | | saving instructions Bswap isn't a simple operation so we need to make sure we are really removing a call to it before doing these simplifications. For the case when both LHS and RHS are bswaps I've allowed it to be moved if either LHS or RHS has a single use since that at least allows us to move it later where it might find another bswap to combine with and it decreases the use count on the other side so maybe the other user can be optimized. Differential Revision: https://reviews.llvm.org/D34974 llvm-svn: 307273
* [InstCombine] Use CmpInst::Predicate with m_Cmp instead of ↵Craig Topper2017-07-051-1/+1
| | | | | | | | ICmpInst::Predicate. NFC There isn't really an ICmpInst version so we're just accessing the CmpInst version through inheritance. llvm-svn: 307199
* [InstCombine] Add a TODO for a probable missing single use check. NFCCraig Topper2017-07-031-0/+2
| | | | | | Will try to fix it soon, but in case I forget. llvm-svn: 307003
* [InstCombine] Support BITWISE_OP( BSWAP(x), CONSTANT ) -> BSWAP( ↵Craig Topper2017-07-031-18/+12
| | | | | | BITWISE_OP(x, BSWAP(CONSTANT) ) ) for splat vectors. llvm-svn: 307002
* [InstCombine] Remove support for BITWISE_OP(CONSTANT, BSWAP(x)) -> ↵Craig Topper2017-07-031-7/+2
| | | | | | | | BSWAP(OP(BSWAP(CONSTANT), x)). Constants were already canonicalized to the right hand side before we got here. llvm-svn: 307000
* [InstCombine] Support BITWISE_OP(BSWAP(A),BSWAP(B))->BSWAP(BITWISE_OP(A, B)) ↵Craig Topper2017-07-031-7/+3
| | | | | | for vectors. llvm-svn: 306999
* [InstCombine] Remove an if that should have been guaranteed by the caller. ↵Craig Topper2017-07-031-4/+2
| | | | | | Replace with an assert. NFC llvm-svn: 306997
* [InstCombine] Fold (a | b) ^ (~a | ~b) --> ~(a ^ b) and (a & b) ^ (~a & ~b) ↵Craig Topper2017-07-021-2/+18
| | | | | | | | | | | | | | | | | | | --> ~(a ^ b) Summary: I came across this while thinking about what would happen if one of the operands in this xor pattern was itself a inverted (A & ~B) ^ (~A & B)-> (A^B). The patterns here assume that the (~a | ~b) will be demorganed to ~(a & b) first. Though I wonder if there's a multiple use case that would prevent the demorgan. Reviewers: spatel Reviewed By: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34870 llvm-svn: 306967
* [InstCombine] In foldXorToXor, move the commutable matcher from the LHS ↵Craig Topper2017-06-301-8/+8
| | | | | | | | | | match to the RHS match. No meaningful change intended. There are two conditions ORed here with similar checks and each contain two matches that must be true for the if to succeed. With the commutable match on the first half of the OR then both ifs basically have the same first part and only the second part distinguishs. With this change we move the commutable match to second half and make the first half unique. This caused some tests to change because we now produce a commuted result, but this shouldn't matter in practice. llvm-svn: 306800
* [InstCombine] In visitXor, use m_Not on the instruction itself instead of ↵Craig Topper2017-06-291-3/+2
| | | | | | looking for all ones in Op1. This is consistent with 3 other not checks before this one. NFCI llvm-svn: 306617
* [InstCombine] Add one use checks to or/and->xnor foldingCraig Topper2017-06-221-6/+8
| | | | | | | | | | If the components of the and/or had multiple uses, this transform created an additional instruction. This patch makes sure we remove one of the components. Differential Revision: https://reviews.llvm.org/D34498 llvm-svn: 306027
* [InstCombine] reverse bitcast + bitwise-logic canonicalization (PR33138)Sanjay Patel2017-06-221-16/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are 2 parts to this patch made simultaneously to avoid a regression. We're reversing the canonicalization that moves bitwise vector ops before bitcasts. We're moving bitwise vector ops *after* bitcasts instead. That's the 1st and 3rd hunks of the patch. The motivation is that there's only one fold that currently depends on the existing canonicalization (see next), but there are many folds that would automatically benefit from the new canonicalization. PR33138 ( https://bugs.llvm.org/show_bug.cgi?id=33138 ) shows why/how we have these patterns in IR. There's an or(and,andn) pattern that requires an adjustment in order to continue matching to 'select' because the bitcast changes position. This match is unfortunately complicated because it requires 4 logic ops with optional bitcast and sext ops. Test diffs: 1. The bitcast.ll and bitcast-bigendian.ll changes show the most basic difference - bitcast comes before logic. 2. There are also tests with no diffs in bitcast.ll that verify that we're still doing folds that were enabled by the previous canonicalization. 3. icmp-xor-signbit.ll shows the payoff. We don't need to adjust existing icmp patterns to look through bitcasts. 4. logical-select.ll contains several tests for the or(and,andn) --> select fold to verify that we are still handling those cases. The lone diff shows the movement of the bitcast from the new canonicalization rule. Differential Revision: https://reviews.llvm.org/D33517 llvm-svn: 306011
* [InstCombine] add peekThroughBitcast() helper; NFCSanjay Patel2017-06-221-6/+2
| | | | | | This is an NFC portion of D33517. We have similar helpers in the backend. llvm-svn: 306008
* [InstCombine] Cleanup using commutable matchers. Make a couple helper ↵Craig Topper2017-06-211-21/+19
| | | | | | methods standalone static functions. Put 'if' around variable declaration instead of after. NFC llvm-svn: 305941
* [InstCombine] fix code/test comments for r305792; NFCSanjay Patel2017-06-201-1/+1
| | | | | | | These diffs were in the last version of the patch in D33342, but I accidentally committed the previous rev. llvm-svn: 305793
* [InstCombine] try to canonicalize xor-of-icmps to and-of-icmpsSanjay Patel2017-06-201-0/+24
| | | | | | | | | | | | | | | | We have a large portfolio of folds for and-of-icmps and or-of-icmps in InstSimplify and InstCombine, but hardly anything for xor-of-icmps. Rather than trying to rethink and translate all of those folds, we can use the truth table definition of xor: X ^ Y --> (X | Y) & !(X & Y) ...to see if we can convert the xor to and/or and then use the existing folds. http://rise4fun.com/Alive/J9v Differential Revision: https://reviews.llvm.org/D33342 llvm-svn: 305792
* [InstCombine] Cleanup some duplicated one use checksCraig Topper2017-06-191-10/+4
| | | | | | | | | | | | | | | | | | | Summary: These 4 patterns have the same one use check repeated twice for each. Once without a cast and one with. But the cast has no effect on what method is called. For the OR case I believe it is always profitable regardless of the number of uses since we'll never increase the instruction count. For the AND case I believe it is profitable if the pair of xors has one use such that we'll get rid of it completely. Or if the C value is something freely invertible, in which case the not doesn't cost anything. Reviewers: spatel, majnemer Reviewed By: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34308 llvm-svn: 305705
* [InstCombine] Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) ↵Craig Topper2017-06-161-31/+58
| | | | | | | | | | | | | | | | == (K1 | K2) if K1 and K2 are a 1-bit mask Summary: This is the demorganed version of the case we already handle for the OR of iszero. Reviewers: spatel Reviewed By: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34244 llvm-svn: 305548
* [InstCombine] Add two FIXMEs for bad single use checks. NFCCraig Topper2017-06-151-0/+4
| | | | llvm-svn: 305510
* [InstCombine] Make the context instruction parameter of foldOrOfICmps a ↵Craig Topper2017-06-151-9/+9
| | | | | | reference to discourage passing nullptr and to remove the '&' from all of the call sites. NFC llvm-svn: 305493
* [InstCombine] Handle (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != ↵Craig Topper2017-06-151-20/+14
| | | | | | | | | | | | (K1 | K2) when the one of the Ands is commuted relative to the other Currently we expect A to be on the same side in both Ands but nothing guarantees that. While there also switch to using matchers for some of the code. Differential Revision: https://reviews.llvm.org/D34230 llvm-svn: 305487
* [InstCombine] Pass a proper context instruction to all of the calls into ↵Craig Topper2017-06-091-3/+3
| | | | | | | | | | | | | | | | InstSimplify Summary: This matches the behavior we already had for compares and makes us consistent everywhere. Reviewers: dberlin, hfinkel, spatel Reviewed By: dberlin Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D33604 llvm-svn: 305049
* [InstCombine][InstSimplify] Use APInt::isNullValue/isOneValue to reduce ↵Craig Topper2017-06-071-10/+11
| | | | | | | | compiled code for comparing APInts with 0 and 1. NFC These methods are specifically optimized to only counting leading zeros without an additional uint64_t compare. llvm-svn: 304876
* [InstCombine] Add an InstCombine specific wrapper around ↵Craig Topper2017-05-251-8/+4
| | | | | | | | isKnownToBeAPowerOfTwo to shorten code. NFC We have wrappers for several other ValueTracking methods that take care of passing all of the analysis and assumption cache parameters. This extends it to isKnownToBeAPowerOfTwo. llvm-svn: 303924
* [InstCombine] add helper to foldXorOfICmps(); NFCISanjay Patel2017-05-181-37/+42
| | | | | | | | | | | Also, fix the old-style capitalization of the related functions and move them to the 'private' section of the class since they are just helpers of the visit* functions. As shown in the post-commit comments for D32143, we are missing folds for xor-of-icmps. llvm-svn: 303381
* [ValueTracking] Replace all uses of ComputeSignBit with computeKnownBits.Craig Topper2017-05-151-3/+2
| | | | | | | | This patch finishes off the conversion of ComputeSignBit to computeKnownBits. Differential Revision: https://reviews.llvm.org/D33166 llvm-svn: 303035
* [InstCombine] remove fold that swaps xor/or with constants; NFCISanjay Patel2017-05-101-12/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2) This canonicalization was added at: https://reviews.llvm.org/rL7264 By moving xors out/down, we can more easily combine constants. I'm adding tests that do not change with this patch, so we can verify that those kinds of transforms are still happening. This is no-functional-change-intended because there's a later fold: // (X^C)|Y -> (X|Y)^C iff Y&C == 0 ...and demanded-bits appears to guarantee that any fold that would have hit the fold we're removing here would be caught by that 2nd fold. Similar reasoning was used in: https://reviews.llvm.org/rL299384 The larger motivation for removing this code is that it could interfere with the fix for PR32706: https://bugs.llvm.org/show_bug.cgi?id=32706 Ie, we're not checking if the 'xor' is actually a 'not', so we could reverse a 'not' optimization and cause an infinite loop by altering an 'xor X, -1'. Differential Revision: https://reviews.llvm.org/D33050 llvm-svn: 302733
* [InstCombine] clean up matchDeMorgansLaws(); NFCISanjay Patel2017-05-091-32/+13
| | | | | | | | | | | | | | The motivation for getting rid of dyn_castNotVal is to allow fixing: https://bugs.llvm.org/show_bug.cgi?id=32706 So this was supposed to be functional-change-intended for the case of inverting constants and applying DeMorgan. However, I can't find any cases where that pattern will actually get to matchDeMorgansLaws() because we have other folds in visitAnd/visitOr that do the same thing. So this ends up just being a clean-up patch with slight efficiency improvement, but no-functional-change-intended. llvm-svn: 302581
* [InstCombine] add folds for not-of-shift-rightSanjay Patel2017-05-081-15/+32
| | | | | | | | | | | | | | | This is another step towards getting rid of dyn_castNotVal, so we can recommit: https://reviews.llvm.org/rL300977 As the tests show, we were missing the lshr case for constants and both ashr/lshr vector splat folds. The ashr case with constant was being performed inefficiently in 2 steps. It's also possible there was a latent bug in that case because we can't do that fold if the constant is positive: http://rise4fun.com/Alive/Bge llvm-svn: 302465
* [InstSimplify] use ConstantRange to simplify or-of-icmpsSanjay Patel2017-05-071-55/+2
| | | | | | | | | | | | | We can simplify (or (icmp X, C1), (icmp X, C2)) to 'true' or one of the icmps in many cases. I had to check some of these with Alive to prove to myself it's right, but everything seems to check out. Eg, the deleted code in instcombine was completely ignoring predicates with mismatched signedness. This is a follow-up to: https://reviews.llvm.org/rL301260 https://reviews.llvm.org/D32143 llvm-svn: 302370
* [InstCombine] don't use DeMorgan's Law on integer constants (2nd try)Sanjay Patel2017-05-021-18/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was originally checked in here: https://reviews.llvm.org/rL301923 And reverted here: https://reviews.llvm.org/rL301924 Because there's a clang test that would fail after this. I fixed/removed the offending CHECK lines in: https://reviews.llvm.org/rL301928 So let's try this again. Original commit message: This is the fold that causes the infinite loop in BoringSSL (https://github.com/google/boringssl/blob/master/crypto/cipher/e_rc2.c) when we fix instcombine demanded bits to prefer 'not' ops as in https://reviews.llvm.org/D32255. There are 2 or 3 problems with dyn_castNotVal, and I don't think we can reinstate https://reviews.llvm.org/D32255 until dyn_castNotVal is completely eliminated. 1. As shown here, it transforms 'not' into random xor. This transform is harmful to SCEV and codegen because 'not' can often be folded while random xor cannot. 2. It does not transform vector constants. This is actually a good thing, but if you don't believe the above argument, then we shouldn't have excluded vectors. 3. It tries to avoid transforming not(not(X)). That's nice, but it doesn't match the greedy nature of instcombine. If we DeMorganize a pattern that has an extra 'not' in it: ~(~(~X) & Y) --> (~X | ~Y) That's just another case of DeMorgan, so we should trust that we'll fold that pattern too: (~X | ~ Y) --> ~(X & Y) Differential Revision: https://reviews.llvm.org/D32665 llvm-svn: 301929
* revert r301923 : [InstCombine] don't use DeMorgan's Law on integer constantsSanjay Patel2017-05-021-21/+18
| | | | | | There's a clang test that is wrongly using -O1 and failing after this commit. llvm-svn: 301924
* [InstCombine] don't use DeMorgan's Law on integer constantsSanjay Patel2017-05-021-18/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | This is the fold that causes the infinite loop in BoringSSL (https://github.com/google/boringssl/blob/master/crypto/cipher/e_rc2.c) when we fix instcombine demanded bits to prefer 'not' ops as in D32255. There are 2 or 3 problems with dyn_castNotVal, and I don't think we can reinstate D32255 until dyn_castNotVal is completely eliminated. 1. As shown here, it transforms 'not' into random xor. This transform is harmful to SCEV and codegen because 'not' can often be folded while random xor cannot. 2. It does not transform vector constants. This is actually a good thing, but if you don't believe the above argument, then we shouldn't have excluded vectors. 3. It tries to avoid transforming not(not(X)). That's nice, but it doesn't match the greedy nature of instcombine. If we DeMorganize a pattern that has an extra 'not' in it: ~(~(~X) & Y) --> (~X | ~Y) That's just another case of DeMorgan, so we should trust that we'll fold that pattern too: (~X | ~ Y) --> ~(X & Y) Differential Revision: https://reviews.llvm.org/D32665 llvm-svn: 301923
* [InstCombine] check one-use before applying DeMorgan nor/nand foldsSanjay Patel2017-05-011-10/+14
| | | | | | | | | | | | | | | If we have ~(~X & Y), it only makes sense to transform it to (X | ~Y) when we do not need the intermediate (~X & Y) value. In that case, we would need an extra instruction to generate ~Y + 'or' (as shown in the test changes). It's ok if we have multiple uses of ~X or Y, however. In those cases, we may not reduce the instruction count or critical path, but we might improve throughput because we can generate ~X and ~Y in parallel. Whether that actually makes perf sense or not for a target is something we can't answer in IR. Differential Revision: https://reviews.llvm.org/D32703 llvm-svn: 301848
* [InstCombine] fix matcher to bind to specific operand (PR32830)Sanjay Patel2017-04-271-1/+1
| | | | | | | Matching any random value would be very wrong: https://bugs.llvm.org/show_bug.cgi?id=32830 llvm-svn: 301594
* InstCombine: Use the new SimplifyQuery versions of Simplify*. Use ↵Daniel Berlin2017-04-261-3/+3
| | | | | | AssumptionCache, DominatorTree, TargetLibraryInfo everywhere. llvm-svn: 301464
* [InstCombine] Add missing commute handling to (A | B) & (B ^ (~A)) -> (A & B)Craig Topper2017-04-251-3/+8
| | | | | | | | The matching here wasn't able to handle all the possible commutes. It always assumed the not would be on the left of the xor, but that's not guaranteed. Differential Revision: https://reviews.llvm.org/D32474 llvm-svn: 301316
* [InstCombine] Use commutable matchers to reduce some code. NFCCraig Topper2017-04-251-4/+2
| | | | llvm-svn: 301294
* [InstSimplify] use ConstantRange to simplify more and-of-icmpsSanjay Patel2017-04-241-40/+0
| | | | | | | | | | | | | We can simplify (and (icmp X, C1), (icmp X, C2)) to one of the icmps in many cases. I had to check some of these with Alive to prove to myself it's right, but everything seems to check out. Eg, the code in instcombine was completely ignoring predicates with mismatched signedness. Handling or-of-icmps would be a follow-up step. Differential Revision: https://reviews.llvm.org/D32143 llvm-svn: 301260
* [InstSimplify] move (A & ~B) | (A ^ B) -> (A ^ B) from InstCombineSanjay Patel2017-04-241-13/+0
| | | | | | | | | | | This is a straight cut and paste, but there's a bigger problem: if this fold exists for simplifyOr, there should be a DeMorganized version for simplifyAnd. But more than that, we have a patchwork of ad hoc logic optimizations in InstCombine. There should be some structure to ensure that we're not missing sibling folds across and/or/xor. llvm-svn: 301213
* [InstCombine] add/move folds for [not]-xorSanjay Patel2017-04-231-38/+67
| | | | | | | | | | | | We handled all of the commuted variants for plain xor already, although they were scattered around and sometimes folded less efficiently using distributive laws. We had no folds for not-xor. Handling all of these patterns consistently is part of trying to reinstate: https://reviews.llvm.org/rL300977 llvm-svn: 301144
* [InstCombine] add pattern matches for commuted variants of xor-to-xorSanjay Patel2017-04-231-34/+55
| | | | | | | | | There's probably some better way to write this that eliminates the code duplication without hurting readability, but at least this eliminates the logic holes and is hopefully slightly more efficient than creating new instructions. llvm-svn: 301129
* [InstCombine] use 'match' to reduce code; NFCISanjay Patel2017-04-221-36/+31
| | | | | | | | | | | The later uses of dyn_castNotVal in this block are either incomplete (doesn't handle vector constants) or overstepping (shouldn't handle constants at all), but this first use is just unnecessary. 'I' is obviously not a constant, and it can't be a not-of-a-not because that would already be instsimplified. llvm-svn: 301088
* [APInt] Rename getSignBit to getSignMaskCraig Topper2017-04-201-2/+2
| | | | | | | | getSignBit is a static function that creates an APInt with only the sign bit set. getSignMask seems like a better name to convey its functionality. In fact several places use it and then store in an APInt named SignMask. Differential Revision: https://reviews.llvm.org/D32108 llvm-svn: 300856
* [InstCombine] Matchers work with both ConstExpr and Instructions.Davide Italiano2017-04-171-2/+2
| | | | | | | | | | So, `cast<Instruction>` is not guaranteed to succeed. Change the code so that we create a new constant and use it in the newly created instruction, as it's done in other places in InstCombine. OK'ed by Sanjay/Craig. Fixes PR32686. llvm-svn: 300495
* [InstCombine] allow (X != C1 && X != C2) and similar patterns to match splat ↵Sanjay Patel2017-04-151-19/+19
| | | | | | vector constants llvm-svn: 300402
* [InstCombine] (X != C1 && X != C2) --> (X | (C1 ^ C2)) != C2Sanjay Patel2017-04-141-36/+65
| | | | | | | | | | ...when C1 differs from C2 by one bit and C1 <u C2: http://rise4fun.com/Alive/Vuo And move related folds to a helper function. This reduces code duplication and will make it easier to remove the scalar-only restriction as a follow-up step. llvm-svn: 300364
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