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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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2012-04-16Remove dead SD nodes after the combining pass. Fixes PR12201.Hal Finkel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154786 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-11Reapply 154397. Original message:Nadav Rotem
Fix a dagcombine optimization which assumes that the vsetcc result type is always of the same size as the compared values. This is ture for SSE/AVX/NEON but not for all targets. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154490 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-10Add a comment noting that the fdiv -> fmul conversion won't generateDuncan Sands
multiplication by a denormal, and some tests checking that. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154431 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-10Revert r154397, which was causing make check failures on the buildbots.Owen Anderson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154414 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-10Fix a dagcombine optimization which assumes that the vsetcc result type is ↵Nadav Rotem
always of the same size as the compared values. This is ture for SSE/AVX/NEON but not for all targets. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154397 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-10Transform div to mul with reciprocal only when fp imm is legal.Anton Korobeynikov
This fixes PR12516 and uncovers one weird problem in legalize (workarounded) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154394 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-10Don't try to zExt just to check if an integer constant is zero, it mightRafael Espindola
not fit in a i64. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154364 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09Pattern match a setcc of boolean value with 0 as a truncate.Rafael Espindola
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154322 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09Remove unnecessary type check when combining and/or/xor of swizzles. Move ↵Craig Topper
some checks to allow better early out. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154309 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09Remove unnecessary 'else' on an 'if' that always returnsCraig Topper
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154308 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09Optimize code slightly. No functionality change.Craig Topper
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154307 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09Replace some explicit checks with asserts for conditions that should never ↵Craig Topper
happen. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154305 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-08Silence sign-compare warning.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154297 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-08Only have codegen turn fdiv by a constant into fmul by the reciprocalDuncan Sands
when -ffast-math, i.e. don't just always do it if the reciprocal can be formed exactly. There is already an IR level transform that does that, and it does it more carefully. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154296 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-071. Remove the part of r153848 which optimizes shuffle-of-shuffle into a newNadav Rotem
shuffle node because it could introduce new shuffle nodes that were not supported efficiently by the target. 2. Add a more restrictive shuffle-of-shuffle optimization for cases where the second shuffle reverses the transformation of the first shuffle. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154266 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-07Convert floating point division by a constant into multiplication by theDuncan Sands
reciprocal if converting to the reciprocal is exact. Do it even if inexact if -ffast-math. This substantially speeds up ac.f90 from the polyhedron benchmarks. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154265 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-04Always compute all the bits in ComputeMaskedBits.Rafael Espindola
This allows us to keep passing reduced masks to SimplifyDemandedBits, but know about all the bits if SimplifyDemandedBits fails. This allows instcombine to simplify cases like the one in the included testcase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02Add predicates for checking whether targets have free FNEG and FABS ↵Owen Anderson
operations, and prevent the DAGCombiner from turning them into bitwise operations if they do. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153901 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02Optimizing swizzles of complex shuffles may generate additional complex ↵Nadav Rotem
shuffles. Do not try to optimize swizzles of shuffles if the source shuffle has more than a single user, except when the source shuffle is also a swizzle. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153864 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-01This commit contains a few changes that had to go in together.Nadav Rotem
1. Simplify xor/and/or (bitcast(A), bitcast(B)) -> bitcast(op (A,B)) (and also scalar_to_vector). 2. Xor/and/or are indifferent to the swizzle operation (shuffle of one src). Simplify xor/and/or (shuff(A), shuff(B)) -> shuff(op (A, B)) 3. Optimize swizzles of shuffles: shuff(shuff(x, y), undef) -> shuff(x, y). 4. Fix an X86ISelLowering optimization which was very bitcast-sensitive. Code which was previously compiled to this: movd (%rsi), %xmm0 movdqa .LCPI0_0(%rip), %xmm2 pshufb %xmm2, %xmm0 movd (%rdi), %xmm1 pshufb %xmm2, %xmm1 pxor %xmm0, %xmm1 pshufb .LCPI0_1(%rip), %xmm1 movd %xmm1, (%rdi) ret Now compiles to this: movl (%rsi), %eax xorl %eax, (%rdi) ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153848 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-27fix what looks like a real logic bug, found by PVS-Studio (part of PR12357)Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153513 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-20When combining (vextract shuffle (load ), <1,u,u,u>), 0) -> (load ), add ↵Craig Topper
users of the final load to the worklist too. Needed by changes I'm preparing to make to X86 backend. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153078 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-19Fix DAG combine which creates illegal vector shuffles. Patch by Heikki Kultala.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153035 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-15When optimizing certain BUILD_VECTOR nodes into other BUILD_VECTOR nodes, ↵Nadav Rotem
add the new node into the work list because there is a potential for further optimizations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152784 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-15Add a xform to the DAG combiner.Bill Wendling
Transform: (fsub x, (fadd x, y)) -> (fneg y) and (fsub x, (fadd y, x)) -> (fneg y) if 'unsafe math' is specified. <rdar://problem/7540295> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152777 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-13Fortify r152675 a bit. Although I'm not able to come up with a test case ↵Evan Cheng
that would trigger the truncation case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152678 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-13DAG combine incorrectly optimize (i32 vextract (v4i16 load $addr), c) toEvan Cheng
(i16 load $addr+c*sizeof(i16)) and replace uses of (i32 vextract) with the i16 load. It should issue an extload instead: (i32 extload $addr+c*sizeof(i16)). rdar://11035895 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152675 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-10Give dagcombiner's worklist some inline capacity.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152454 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-06Extend r148086 to check for [r +/- reg] address mode. This fixes queens ↵Evan Cheng
performance regression (due to increased register pressure from overly aggressive pre-inc formation). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152162 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-06Make it possible for a target to mark FSUB as Expand. This requires ↵Owen Anderson
providing a default expansion (FADD+FNEG), and teaching DAGCombine not to form FSUBs post-legalize if they are not legal. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152079 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-20Teach the DAGCombiner that certain loadext nodes followed by ANDs can be ↵James Molloy
converted to zeroexts. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150957 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16Remove extraneous #include and spelling mistake introduced in r150669.James Molloy
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150670 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16Modify the algorithm when traversing the DAGCombiner's worklist to be O(log ↵James Molloy
N) for all operations. This fixes a horrible worst case with lots of nodes where 99% of the time was being spent in std::remove. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150669 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-13Fix a bug in DAGCombine for the optimization of BUILD_VECTOR. We cant ↵Nadav Rotem
generate a shuffle node from two vectors of different types. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150383 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-12This patch addresses the problem of poor code generation for the zextNadav Rotem
v8i8 -> v8i32 on AVX machines. The codegen often scalarizes ANY_EXTEND nodes. The DAGCombiner has two optimizations that can mitigate the problem. First, if all of the operands of a BUILD_VECTOR node are extracted from an ZEXT/ANYEXT nodes, then it is possible to create a new simplified BUILD_VECTOR which uses UNDEFS/ZERO values to eliminate the scalar ZEXT/ANYEXT nodes. Second, another dag combine optimization lowers BUILD_VECTOR into a shuffle vector instruction. In the case of zext v8i8->v8i32 on AVX, a value in an XMM register is to be shuffled into a wide YMM register. This patch modifes the second optimization and allows the creation of shuffle vectors even when the newly generated vector and the original vector from which we extract the values are of different types. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150340 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-05Add additional documentation to the extract-and-trunc dagcombine optimization.Nadav Rotem
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149823 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-03The type-legalizer often scalarizes code. One of the common patterns is ↵Nadav Rotem
extract-and-truncate. In this patch we optimize this pattern and convert the sequence into extract op of a narrow type. This allows the BUILD_VECTOR dag optimizations to construct efficient shuffle operations in many cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149692 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-17Transform: (EXTRACT_VECTOR_ELT( VECTOR_SHUFFLE )) -> EXTRACT_VECTOR_ELT.Nadav Rotem
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148337 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-17Teach DAG combiner to turn a BUILD_VECTOR of UNDEFs into an UNDEF of vector ↵Craig Topper
type. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148297 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-15DAGCombiner: Deduplicate code.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148217 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-13DAGCombine's logic for forming pre- and post- indexed loads / stores were beingEvan Cheng
overly conservative. It was concerned about cases where it would prohibit folding simple [r, c] addressing modes. e.g. ldr r0, [r2] ldr r1, [r2, #4] => ldr r0, [r2], #4 ldr r1, [r2] Change the logic to look for such cases which allows it to form indexed memory ops more aggressively. rdar://10674430 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148086 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-11Teach the X86 instruction selection to do some heroic transforms toChandler Carruth
detect a pattern which can be implemented with a small 'shl' embedded in the addressing mode scale. This happens in real code as follows: unsigned x = my_accelerator_table[input >> 11]; Here we have some lookup table that we look into using the high bits of 'input'. Each entity in the table is 4-bytes, which means this implicitly gets turned into (once lowered out of a GEP): *(unsigned*)((char*)my_accelerator_table + ((input >> 11) << 2)); The shift right followed by a shift left is canonicalized to a smaller shift right and masking off the low bits. That hides the shift right which x86 has an addressing mode designed to support. We now detect masks of this form, and produce the longer shift right followed by the proper addressing mode. In addition to saving a (rather large) instruction, this also reduces stalls in Intel chips on benchmarks I've measured. In order for all of this to work, one part of the DAG needs to be canonicalized *still further* than it currently is. This involves removing pointless 'trunc' nodes between a zextload and a zext. Without that, we end up generating spurious masks and hiding the pattern. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147936 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07Replace some uses of hasNUsesOfValue(0, X) with !hasAnyUseOfValue(X)Craig Topper
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147733 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07Add some DAG combines for SUBC/SUBE. If nothing uses the carry/borrow out of ↵Craig Topper
subc, turn it into a sub. Turn (subc x, x) into 0 with no borrow. Turn (subc x, 0) into x with no borrow. Turn (subc -1, x) into (xor x, -1) with no borrow. Turn sube with no borrow in into subc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147728 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-05Prevent a DAGCombine from firing where there are two uses ofChandler Carruth
a combined-away node and the result of the combine isn't substantially smaller than the input, it's just canonicalized. This is the first part of a significant (7%) performance gain for Snappy's hot decompression loop. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147604 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-04Implement VECTOR_SHUFFLE canonicalizations during DAG combine.Craig Topper
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147525 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-26Make sure DAGCombiner doesn't introduce multiple loads from the same memory ↵Eli Friedman
location. PR10747, part 2. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147283 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-13Initial CodeGen support for CTTZ/CTLZ where a zero input produces anChandler Carruth
undefined result. This adds new ISD nodes for the new semantics, selecting them when the LLVM intrinsic indicates that the undef behavior is desired. The new nodes expand trivially to the old nodes, so targets don't actually need to do anything to support these new nodes besides indicating that they should be expanded. I've done this for all the operand types that I could figure out for all the targets. Owners of various targets, please review and let me know if any of these are incorrect. Note that the expand behavior is *conservatively correct*, and exactly matches LLVM's current behavior with these operations. Ideally this patch will not change behavior in any way. For example the regtest suite finds the exact same instruction sequences coming out of the code generator. That's why there are no new tests here -- all of this is being exercised by the existing test suite. Thanks to Duncan Sands for reviewing the various bits of this patch and helping me get the wrinkles ironed out with expanding for each target. Also thanks to Chris for clarifying through all the discussions that this is indeed the approach he was looking for. That said, there are likely still rough spots. Further review much appreciated. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146466 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07Zap unnecessary isIntDivCheap() check. PR11485. No testcase because this ↵Eli Friedman
doesn't affect any in-tree target. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146015 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07Fix an optimization involving EXTRACT_SUBVECTOR in DAGCombine so it behaves ↵Eli Friedman
correctly. PR11494. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145996 91177308-0d34-0410-b5e6-96231b3b80d8
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