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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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2008-08-29Back out 55498. It broken Apple style bootstrapping.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55549 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-28erect abstraction boundaries for accessing SDValue members, rename Val -> ↵Gabor Greif
Node to reflect semantics git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55504 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-28Optimize DAGCombiner's worklist processing. Previously it startedDan Gohman
its work by putting all nodes in the worklist, requiring a big dynamic allocation. Now, DAGCombiner just iterates over the AllNodes list and maintains a worklist for nodes that are newly created or need to be revisited. This allows the worklist to stay small in most cases, so it can be a SmallVector. This has the side effect of making DAGCombine not miss a folding opportunity in alloca-align-rounding.ll. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55498 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-26disallow direct access to SDValue::ResNo, provide a getter insteadGabor Greif
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55394 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-20Disable DAGCombine's alignment inference in "fast" codegen mode.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55059 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-14Improve support for vector casts in LLVM IR and CodeGen.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54784 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-11Take the FrameOffset into account when computing the alignmentDan Gohman
of stack objects. This fixes PR2656. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54646 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-31Improve dagcombining for sext-loads and sext-in-reg nodes.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54239 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-27Rename SDOperand to SDValue.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54128 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-27Tidy SDNode::use_iterator, and complete the transition to have itDan Gohman
parallel its analogue, Value::value_use_iterator. The operator* method now returns the user, rather than the use. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54127 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-22Fix pr2566: incorrect assumption about bit_convert. It doesn't not have to ↵Evan Cheng
output a vector value. Patch by Nicolas Capens! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53932 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-21Add titles to the various SelectionDAG viewGraph callsDan Gohman
that include useful information like the name of the block being viewed and the current phase of compilation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53872 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-21Add VerifyNode, a place to put sanity checks onDuncan Sands
generic SDNode's (nodes with their own constructors should do sanity checking in the constructor). Add sanity checks for BUILD_VECTOR and fix all the places that were producing bogus BUILD_VECTORs, as found by "make check". My favorite is the BUILD_VECTOR with only two operands that was being used to build a vector with four elements! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53850 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-18Revert 53729, after waking up in the middle ofDuncan Sands
the night realising that it was wrong :) I think the reason the same type was being used for the shufflevec of indices as for the actual indices is so that if one of them needs splitting then so does the other. After my patch it might be that the indices need splitting but not the rest, yet there is no good way of handling that. I think the right solution is to not have the shufflevec be an operand at all: just have it be the list of numbers it actually is, stored as extra info in the node. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53768 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17Use a legal type for elements of the vector_shuffleDuncan Sands
mask. These are just indices into the shuffled vector so their type is unrelated to the type of the shuffled elements (which is what was being used before). This fixes vec_shuffle-11.ll when using LegalizeTypes. What seems to have happened is that Dan's recent change r53687, which corrected the result type of the shuffle, somehow caused LegalizeTypes to notice that the mask operand was a BUILD_VECTOR with a legal type but elements of an illegal type (i64). LegalizeTypes legalized this by introducing a new BUILD_VECTOR of i32 and bitcasting it to the old type. But the mask operand is not supposed to be a bitcast but a straight BUILD_VECTOR of constants, causing a crash. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53729 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-16Fix the result type of a VECTOR_SHUFFLE+BIT_CONVERT dagcombine. ThisDan Gohman
was turned up by some new SelectionDAG assertion checks that I'm working on. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53687 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-30Use reserve.Dan Gohman
SelectionDAG::allnodes_size is linear, but that doesn't appear to outweigh the benefit of reducing heap traffic. If it does become a problem, we should teach SelectionDAG to keep a count of how many nodes are live, because there are several other places where that information would be useful as well. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52926 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-28When folding a bitcast into a load or store, preserve the alignmentDan Gohman
information of the original load or store, which is checked to be at least as good, and possibly better. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52849 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-26duncan points out that isOperationLegal includes a check forChris Lattner
type legality. Thanks Duncan! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52786 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-26when we know the signbit of an input to uint_to_fp is zero,Chris Lattner
change it to sint_to_fp on targets where that is cheaper (and visaversa of course). This allows us to compile uint_to_fp to: _test: movl 4(%esp), %eax shrl $23, %eax cvtsi2ss %eax, %xmm0 movl 8(%esp), %eax movss %xmm0, (%eax) ret instead of: .align 3 LCPI1_0: ## double .long 0 ## double least significant word 4.5036e+15 .long 1127219200 ## double most significant word 4.5036e+15 .text .align 4,0x90 .globl _test _test: subl $12, %esp movl 16(%esp), %eax shrl $23, %eax movl %eax, (%esp) movl $1127219200, 4(%esp) movsd (%esp), %xmm0 subsd LCPI1_0, %xmm0 cvtsd2ss %xmm0, %xmm0 movl 20(%esp), %eax movss %xmm0, (%eax) addl $12, %esp ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52747 91177308-0d34-0410-b5e6-96231b3b80d8
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