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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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2008-06-23Duncan pointed out this code could be tidied.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52624 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-21Simplify some getNode calls.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52604 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16Allow these transforms for types like i256 whileDuncan Sands
still excluding types like i1 (not byte sized) and i120 (loading an i120 requires loading an i64, an i32, an i16 and an i8, which is expensive). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52310 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-15The transforms in visitEXTRACT_VECTOR_ELT areDuncan Sands
not valid if the load is volatile. Hopefully all wrong DAG combiner transforms of volatile loads and stores have now been caught. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52293 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-14Remove a redundant AfterLegalize check. TurnDuncan Sands
on some code when !AfterLegalize - but since this whole code section is turned off by an "if (0)" it's not really turning anything on. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52276 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-13Disable some DAG combiner optimizations that may beDuncan Sands
wrong for volatile loads and stores. In fact this is almost all of them! There are three types of problems: (1) it is wrong to change the width of a volatile memory access. These may be used to do memory mapped i/o, in which case a load can have an effect even if the result is not used. Consider loading an i32 but only using the lower 8 bits. It is wrong to change this into a load of an i8, because you are no longer tickling the other three bytes. It is also unwise to make a load/store wider. For example, changing an i16 load into an i32 load is wrong no matter how aligned things are, since the fact of loading an additional 2 bytes can have i/o side-effects. (2) it is wrong to change the number of volatile load/stores: they may be counted by the hardware. (3) it is wrong to change a volatile load/store that requires one memory access into one that requires several. For example on x86-32, you can store a double in one processor operation, but to store an i64 requires two (two i32 stores). In a multi-threaded program you may want to bitcast an i64 to a double and store as a double because that will occur atomically, and be indivisible to other threads. So it would be wrong to convert the store-of-double into a store of an i64, because this will become two i32 stores - no longer atomic. My policy here is to say that the number of processor operations for an illegal operation is undefined. So it is alright to change a store of an i64 (requires at least two stores; but could be validly lowered to memcpy for example) into a store of double (one processor op). In short, if the new store is legal and has the same size then I say that the transform is ok. It would also be possible to say that transforms are always ok if before they were illegal, whether after they are illegal or not, but that's more awkward to do and I doubt it buys us anything much. However this exposed an interesting thing - on x86-32 a store of i64 is considered legal! That is because operations are marked legal by default, regardless of whether the type is legal or not. In some ways this is clever: before type legalization this means that operations on illegal types are considered legal; after type legalization there are no illegal types so now operations are only legal if they really are. But I consider this to be too cunning for mere mortals. Better to do things explicitly by testing AfterLegalize. So I have changed things so that operations with illegal types are considered illegal - indeed they can never map to a machine operation. However this means that the DAG combiner is more conservative because before it was "accidentally" performing transforms where the type was illegal because the operation was nonetheless marked legal. So in a few such places I added a check on AfterLegalize, which I suppose was actually just forgotten before. This causes the DAG combiner to do slightly more than it used to, which resulted in the X86 backend blowing up because it got a slightly surprising node it wasn't expecting, so I tweaked it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52254 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-11Sometimes (rarely) nodes held in LegalizeTypesDuncan Sands
maps can be deleted. This happens when RAUW replaces a node N with another equivalent node E, deleting the first node. Solve this by adding (N, E) to ReplacedNodes, which is already used to remap nodes to replacements. This means that deleted nodes are being allowed in maps, which can be delicate: the memory may be reused for a new node which might get confused with the old deleted node pointer hanging around in the maps, so detect this and flush out maps if it occurs (ExpungeNode). The expunging operation is expensive, however it never occurs during a llvm-gcc bootstrap or anywhere in the nightly testsuite. It occurs three times in "make check": Alpha/illegal-element-type.ll, PowerPC/illegal-element-type.ll and X86/mmx-shift.ll. If expunging proves to be too expensive then there are other more complicated ways of solving the problem. In the normal case this patch adds the overhead of a few more map lookups, which is hopefully negligable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52214 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-09Various tweaks related to apint codegen. No functionalityDuncan Sands
change for non-funky-sized integers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52151 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-09Remove some DAG combiner assumptions about sizesDuncan Sands
of integer types. Fix the isMask APInt method to actually work (hopefully) rather than crashing because it adds apints of different bitwidths. It looks like isShiftedMask is also broken, but I'm leaving that one to the APInt people (it is not used anywhere). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52142 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-08Remove comparison methods for MVT. The main causeDuncan Sands
of apint codegen failure is the DAG combiner doing the wrong thing because it was comparing MVT's using < rather than comparing the number of bits. Removing the < method makes this mistake impossible to commit. Instead, add helper methods for comparing bits and use them. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52098 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-06Wrap MVT::ValueType in a struct to get type safetyDuncan Sands
and better control the abstraction. Rename the type to MVT. To update out-of-tree patches, the main thing to do is to rename MVT::ValueType to MVT, and rewrite expressions like MVT::getSizeInBits(VT) in the form VT.getSizeInBits(). Use VT.getSimpleVT() to extract a MVT::SimpleValueType for use in switch statements (you will get an assert failure if VT is an extended value type - these shouldn't exist after type legalization). This results in a small speedup of codegen and no new testsuite failures (x86-64 linux). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52044 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-23Add #includes to make some dependencies explicit.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51496 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-20Code simplification.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51345 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-13Instead of a vector load, shuffle and then extract an element. Load the ↵Evan Cheng
element from address with an offset. pshufd $1, (%rdi), %xmm0 movd %xmm0, %eax => movl 4(%rdi), %eax git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51026 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-12Xform bitconvert(build_pair(load a, load b)) to a single load if the load ↵Evan Cheng
locations are at the right offset from each other. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51008 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-28Evan pointed out that folding sext to zext may not be correctDan Gohman
if the zext is not legal. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50368 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-28Teach DAGCombine to convert (sext x) to (zext x) when theDan Gohman
sign-bit of x is known to be zero. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50357 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-16Ongoing work on improving the instruction selection infrastructure:Roman Levenstein
Rename SDOperandImpl back to SDOperand. Introduce the SDUse class that represents a use of the SDNode referred by an SDOperand. Now it is more similar to Use/Value classes. Patch is approved by Dan Gohman. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49795 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-07Re-commit of the r48822, where the infinite looping problem discoveredRoman Levenstein
by Dan Gohman is fixed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49330 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-03Backing out 48222 temporarily.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49124 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-31Fix a DAGCombiner optimization to respect volatile qualification.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48994 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-26Use a linked data structure for the uses lists of an SDNode, just like Roman Levenstein
LLVM Value/Use does and MachineRegisterInfo/MachineOperand does. This allows constant time for all uses list maintenance operations. The idea was suggested by Chris. Reviewed by Evan and Dan. Patch is tested and approved by Dan. On normal use-cases compilation speed is not affected. On very big basic blocks there are compilation speedups in the range of 15-20% or even better. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48822 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-25Handle a special case xor undef, undef -> 0. Technically this should be ↵Evan Cheng
transformed to undef. But this is such a common idiom (misuse) we are going to handle it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48792 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-24Remove an unneeded test.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48755 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-22Teach DAG combiner to commute commutable binary nodes in order to achieve ↵Evan Cheng
sdisel CSE. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48673 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-20Check even more carefully before applying this DAGCombine transform.Christopher Lamb
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48580 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-20Fix this xform: (sra (shl X, m), result_size) -> (sign_extend (trunc (shl X, ↵Evan Cheng
result_size - n - m))) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48578 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-19Fix X86's isTruncateFree to not claim that truncate to i1 is free. This ↵Christopher Lamb
fixes Bill's testcase that failed for r48491. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48542 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-18Temporarily revert r48491. It's breaking test/CodeGen/X86/xorl.ll.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48510 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-18Target independent DAG transform to use truncate for field extraction + sign ↵Christopher Lamb
extend on targets where this is profitable. Passes nightly on x86-64. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48491 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-13More APInt-ification.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48344 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-12Clean up my own mess.Evan Cheng
X86 lowering normalize vector 0 to v4i32. However DAGCombine can fold (sub x, x) -> 0 after legalization. It can create a zero vector of a type that's not expected (e.g. v8i16). We don't want to disable the optimization since leaving a (sub x, x) is really bad. Add isel patterns for other types of vector 0 to ensure correctness. It's highly unlikely to happen other than in bugpoint reduced test cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48279 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-12Total brain cramp.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48274 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-10Somewhat better solution.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48170 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-10Give TargetLowering::getSetCCResultType() a parameter so that ISD::SETCC'sScott Michel
return ValueType can depend its operands' ValueType. This is a cosmetic change, no functionality impacted. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48145 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-10DohEvan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48140 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-10Avoid creating BUILD_VECTOR of all zero elements of "non-normalized" type ↵Evan Cheng
(e.g. v8i16 on x86) after legalizer. Instruction selection does not expect to see them. In all likelihood this can only be an issue in a bugpoint reduced test case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48136 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-04Rename isOperand() to isOperandOf() (and other similar methods). It always ↵Evan Cheng
confuses me. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47872 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-03Misc. APInt-ification in the DAGCombiner.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47869 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27Convert SimplifyDemandedMask and ShrinkDemandedConstant to use APInt.Dan Gohman
Change several cases in SimplifyDemandedMask that don't ever do any simplifying to reuse the logic in ComputeMaskedBits instead of duplicating it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47648 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-26Fix PR2096, a regression introduced with my patch last night. ThisChris Lattner
also fixes cfrac, flops, and 175.vpr git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47605 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-26Fix isNegatibleForFree to not return true for ConstantFP nodes Chris Lattner
after legalize. Just because a constant is legal (e.g. 0.0 in SSE) doesn't mean that its negated value is legal (-0.0). We could make this stronger by checking to see if the negated constant is actually legal post negation, but it doesn't seem like a big deal. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47591 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-25Convert MaskedValueIsZero and all its users to use APInt. Also addDan Gohman
a SignBitIsZero function to simplify a common use case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47561 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Add explicit keywords.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47382 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Convert DAGCombiner to use the APInt form of ComputeMaskedBits.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47381 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-20Update gcc 4.3 warnings fix patch with recent head changesAnton Korobeynikov
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47368 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18- When DAG combiner is folding a bit convert into a BUILD_VECTOR, it should ↵Evan Cheng
check if it's essentially a SCALAR_TO_VECTOR. Avoid turning (v8i16) <10, u, u, u> to <10, 0, u, u, u, u, u, u>. Instead, simply convert it to a SCALAR_TO_VECTOR of the proper type. - X86 now normalize SCALAR_TO_VECTOR to (BIT_CONVERT (v4i32 SCALAR_TO_VECTOR)). Get rid of X86ISD::S2VEC. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47290 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-13teach dag combiner how to eliminate MERGE_VALUES nodes.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47052 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-11Add a isBigEndian method to complement isLittleEndian.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46954 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-10Return "(c1 + c2)" instead of yet another ADD node (which made this aBill Wendling
no-op). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46922 91177308-0d34-0410-b5e6-96231b3b80d8