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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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2008-02-03the world doesn't need my debugging code.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46678 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-03Change the 'global modification' APIs in SelectionDAG to take a newChris Lattner
DAGUpdateListener object pointer instead of just returning a vector of deleted nodes. This makes the interfaces more efficient (no more allocating a vector [at least a malloc], filling it in, then walking it) and more clean. This also allows the client to be notified of nodes that are *changed* but not deleted. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46677 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-30Factor the addressing mode and the load/store VT out of LoadSDNodeDan Gohman
and StoreSDNode into their common base class LSBaseSDNode. Member functions getLoadedVT and getStoredVT are replaced with the common getMemoryVT to simplify code that will handle both loads and stores. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46538 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-29Use empty() instead of comparing size() with zero.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46514 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-27Fix PowerPC/./2007-10-18-PtrArithmetic.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46424 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-27fix a crash on CodeGen/X86/vector-rem.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46422 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-27Implement some dag combines that allow doing fneg/fabs/fcopysign in integerChris Lattner
registers if used by a bitconvert or using a bitconvert. This allows us to avoid constant pool loads and use cheaper integer instructions when the values come from or end up in integer regs anyway. For example, we now compile CodeGen/X86/fp-in-intregs.ll to: _test1: movl $2147483648, %eax xorl 4(%esp), %eax ret _test2: movl $1065353216, %eax orl 4(%esp), %eax andl $3212836864, %eax ret Instead of: _test1: movss 4(%esp), %xmm0 xorps LCPI2_0, %xmm0 movd %xmm0, %eax ret _test2: movss 4(%esp), %xmm0 andps LCPI3_0, %xmm0 movss LCPI3_1, %xmm1 andps LCPI3_2, %xmm1 orps %xmm0, %xmm1 movd %xmm1, %eax ret bitconverts can happen due to various calling conventions that require fp values to passed in integer regs in some cases, e.g. when returning a complex. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46414 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-26Infer alignment of loads and increase their alignment when we can tell they are Chris Lattner
from the stack. This allows us to compile stack-align.ll to: _test: movsd LCPI1_0, %xmm0 movapd %xmm0, %xmm1 *** andpd 4(%esp), %xmm1 andpd _G, %xmm0 addsd %xmm1, %xmm0 movl 20(%esp), %eax movsd %xmm0, (%eax) ret instead of: _test: movsd LCPI1_0, %xmm0 ** movsd 4(%esp), %xmm1 ** andpd %xmm0, %xmm1 andpd _G, %xmm0 addsd %xmm1, %xmm0 movl 20(%esp), %eax movsd %xmm0, (%eax) ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46401 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-26Fix some bugs in SimplifyNodeWithTwoResults where it would call deletenode to Chris Lattner
delete a node even if it was not dead in some cases. Instead, just add it to the worklist. Also, make sure to use the CombineTo methods, as it was doing things that were unsafe: the top level combine loop could touch dangling memory. This fixes CodeGen/Generic/2008-01-25-dag-combine-mul.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46384 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-25reduce indentationChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46377 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-25Add skeletal code to increase the alignment of loads and stores whenChris Lattner
we can infer it. This will eventually help stuff, though it doesn't do much right now because all fixed FI's have an alignment of 1. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46349 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24clarify a comment, thanks Duncan.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46313 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24Fix this buggy transformation. Two observations:Chris Lattner
1. we already know the value is dead, so don't bother replacing it with undef. 2. The very case the comment describes actually makes the load live which asserts in deletenode. If we do the replacement and the node becomes live, just treat it as new. This fixes a failure on X86/2008-01-16-InvalidDAGCombineXform.ll with some local changes in my tree. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46306 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24The dag combiner is missing revisiting nodes that it really should, and thus ↵Chris Lattner
leaving dead stuff around. This gets fed into the isel pass and causes certain foldings from happening because nodes have extraneous uses floating around. For example, if we turned foo(bar(x)) -> baz(x), we sometimes left bar(x) around. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46305 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24fold fp_round(fp_round(x)) -> fp_round(x).Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46304 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-17This commit changes:Chris Lattner
1. Legalize now always promotes truncstore of i1 to i8. 2. Remove patterns and gunk related to truncstore i1 from targets. 3. Rename the StoreXAction stuff to TruncStoreAction in TLI. 4. Make the TLI TruncStoreAction table a 2d table to handle from/to conversions. 5. Mark a wide variety of invalid truncstores as such in various targets, e.g. X86 currently doesn't support truncstore of any of its integer types. 6. Add legalize support for truncstores with invalid value input types. 7. Add a dag combine transform to turn store(truncate) into truncstore when safe. The later allows us to compile CodeGen/X86/storetrunc-fp.ll to: _foo: fldt 20(%esp) fldt 4(%esp) faddp %st(1) movl 36(%esp), %eax fstps (%eax) ret instead of: _foo: subl $4, %esp fldt 24(%esp) fldt 8(%esp) faddp %st(1) fstps (%esp) movl 40(%esp), %eax movss (%esp), %xmm0 movss %xmm0, (%eax) addl $4, %esp ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46140 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-17code cleanups, no functionality change.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46126 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-17* Introduce a new SelectionDAG::getIntPtrConstant methodChris Lattner
and switch various codegen pieces and the X86 backend over to using it. * Add some comments to SelectionDAGNodes.h * Introduce a second argument to FP_ROUND, which indicates whether the FP_ROUND changes the value of its input. If not it is safe to xform things like fp_extend(fp_round(x)) -> x. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46125 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-16Fixes a nasty dag combiner bug that causes a bunch of tests to fail at -O0.Evan Cheng
It's not safe to use the two value CombineTo variant to combine away a dead load. e.g. v1, chain2 = load chain1, loc v2, chain3 = load chain2, loc v3 = add v2, c Now we replace use of v1 with undef, use of chain2 with chain1. ReplaceAllUsesWith() will iterate through uses of the first load and update operands: v1, chain2 = load chain1, loc v2, chain3 = load chain1, loc v3 = add v2, c Now the second load is the same as the first load, SelectionDAG cse will ensure the use of second load is replaced with the first load. v1, chain2 = load chain1, loc v3 = add v1, c Then v1 is replaced with undef and bad things happen. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46099 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-16Factor the ReachesChainWithoutSideEffects out of dag combiner into Chris Lattner
a public SDOperand::reachesChainWithoutSideEffects method. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46050 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-08Make load->store deletion a bit smarter. This allows us to compile this:Chris Lattner
void test(long long *P) { *P ^= 1; } into just: _test: movl 4(%esp), %eax xorl $1, (%eax) ret instead of code like this: _test: movl 4(%esp), %ecx xorl $1, (%ecx) movl 4(%ecx), %edx movl %edx, 4(%ecx) ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45762 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29Remove attribution from file headers, per discussion on llvmdev.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45418 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29make sure not to zap volatile stores, thanks a lot to Dale for noticing this!Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45402 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29don't fold fp_round(fp_extend(load)) -> fp_round(extload)Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45400 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29Delete a store whose input is a load from the same pointer:Chris Lattner
x = load p store x -> p git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45398 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-22Tell TargetLoweringOpt whether it is running beforeChris Lattner
or after legalize. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45321 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-19Don't leave newly created nodes around if it turns out they are not needed.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45186 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-06Redo previous patch so optimization only done for i1.Dale Johannesen
Simpler and safer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44663 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-06third time around: instead of disabling this completely,Chris Lattner
only disable it if we don't know it will be obviously profitable. Still fixme, but less so. :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44658 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-06Actually, disable this code for now. More analysis and improvements toChris Lattner
the X86 backend are needed before this should be enabled by default. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44657 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-06implement a readme entry, compiling the code into:Chris Lattner
_foo: movl $12, %eax andl 4(%esp), %eax movl _array(%eax), %eax ret instead of: _foo: movl 4(%esp), %eax shrl $2, %eax andl $3, %eax movl _array(,%eax,4), %eax ret As it turns out, this triggers all the time, in a wide variety of situations, for example, I see diffs like this in various programs: - movl 8(%eax), %eax - shll $2, %eax - andl $1020, %eax - movl (%esi,%eax), %eax + movzbl 8(%eax), %eax + movl (%esi,%eax,4), %eax - shll $2, %edx - andl $1020, %edx - movl (%edi,%edx), %edx + andl $255, %edx + movl (%edi,%edx,4), %edx Unfortunately, I also see stuff like this, which can be fixed in the X86 backend: - andl $85, %ebx - addl _bit_count(,%ebx,4), %ebp + shll $2, %ebx + andl $340, %ebx + addl _bit_count(%ebx), %ebp git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44656 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-06Fix PR1842.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44649 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-26Don't lower srem/urem X%C to X-X/C*C unless the division is actuallyDan Gohman
optimized. This avoids creating illegal divisions when the combiner is running after legalize; this fixes PR1815. Also, it produces better code in the included testcase by avoiding the subtract and multiply when the division isn't optimized. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44341 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-09Move MinAlign to MathExtras.h.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43944 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-09Fix some load/store logic that would be wrong forDuncan Sands
apints on big-endian machines if the bitwidth is not a multiple of 8. Introduce a new helper, MVT::getStoreSizeInBits, and use it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43934 91177308-0d34-0410-b5e6-96231b3b80d8
2007-11-08If both parts of smul_lohi, etc. are used, don't simplify. If only one part ↵Evan Cheng
is used, try simplify it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43888 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-30Typo.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43511 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-29Fix a DAGCombiner abort on a bitcast from a scalar to a vector.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43470 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-29Enable more fold (sext (load x)) -> (sext (truncate (sextload x)))Evan Cheng
transformation. Previously, it's restricted by ensuring the number of load uses is one. Now the restriction is loosened up by allowing setcc uses to be "extended" (e.g. setcc x, c, eq -> setcc sext(x), sext(c), eq). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43465 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-28The guaranteed alignment of ptr+offset is only the minimum ofDuncan Sands
of offset and the alignment of ptr if these are both powers of 2. While the ptr alignment is guaranteed to be a power of 2, there is no reason to think that offset is. For example, if offset is 12 (the size of a long double on x86-32 linux) and the alignment of ptr is 8, then the alignment of ptr+offset will in general be 4, not 8. Introduce a function MinAlign, lifted from gcc, for computing the minimum guaranteed alignment. I've tried to fix up everywhere under lib/CodeGen/SelectionDAG/. I also changed some places that weren't wrong (because both values were a power of 2), as a defensive change against people copying and pasting the code. Hopefully someone who cares about alignment will review the rest of LLVM and fix up the remaining places. Since I'm on x86 I'm not very motivated to do this myself... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43421 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-19Redo "last ppc long double fix" as Chris wants.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43189 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-19More ppcf128 issues (maybe the last)?Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43160 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-16Disable attempts to constant fold PPC f128.Dale Johannesen
Remove the assumption that this will happen from various places. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43053 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-15One mundane change: Change ReplaceAllUsesOfValueWith to *optionally* Chris Lattner
take a deleted nodes vector, instead of requiring it. One more significant change: Implement the start of a legalizer that just works on types. This legalizer is designed to run before the operation legalizer and ensure just that the input dag is transformed into an output dag whose operand and result types are all legal, even if the operations on those types are not. This design/impl has the following advantages: 1. When finished, this will *significantly* reduce the amount of code in LegalizeDAG.cpp. It will remove all the code related to promotion and expansion as well as splitting and scalarizing vectors. 2. The new code is very simple, idiomatic, and modular: unlike LegalizeDAG.cpp, it has no 3000 line long functions. :) 3. The implementation is completely iterative instead of recursive, good for hacking on large dags without blowing out your stack. 4. The implementation updates nodes in place when possible instead of deallocating and reallocating the entire graph that points to some mutated node. 5. The code nicely separates out handling of operations with invalid results from operations with invalid operands, making some cases simpler and easier to understand. 6. The new -debug-only=legalize-types option is very very handy :), allowing you to easily understand what legalize types is doing. This is not yet done. Until the ifdef added to SelectionDAGISel.cpp is enabled, this does nothing. However, this code is sufficient to legalize all of the code in 186.crafty, olden and freebench on an x86 machine. The biggest issues are: 1. Vectors aren't implemented at all yet 2. SoftFP is a mess, I need to talk to Evan about it. 3. No lowering to libcalls is implemented yet. 4. Various operations are missing etc. 5. There are FIXME's for stuff I hax0r'd out, like softfp. Hey, at least it is a step in the right direction :). If you'd like to help, just enable the #ifdef in SelectionDAGISel.cpp and compile code with it. If this explodes it will tell you what needs to be implemented. Help is certainly appreciated. Once this goes in, we can do three things: 1. Add a new pass of dag combine between the "type legalizer" and "operation legalizer" passes. This will let us catch some long-standing isel issues that we miss because operation legalization often obfuscates the dag with target-specific nodes. 2. We can rip out all of the type legalization code from LegalizeDAG.cpp, making it much smaller and simpler. When that happens we can then reimplement the core functionality left in it in a much more efficient and non-recursive way. 3. Once the whole legalizer is non-recursive, we can implement whole-function selectiondags maybe... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42981 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-13Enhance the truncstore optimization code to handle shiftedChris Lattner
values and propagate demanded bits through them in simple cases. This allows this code: void foo(char *P) { strcpy(P, "abc"); } to compile to: _foo: ldrb r3, [r1] ldrb r2, [r1, #+1] ldrb r12, [r1, #+2]! ldrb r1, [r1, #+1] strb r1, [r0, #+3] strb r2, [r0, #+1] strb r12, [r0, #+2] strb r3, [r0] bx lr instead of: _foo: ldrb r3, [r1, #+3] ldrb r2, [r1, #+2] orr r3, r2, r3, lsl #8 ldrb r2, [r1, #+1] ldrb r1, [r1] orr r2, r1, r2, lsl #8 orr r3, r2, r3, lsl #16 strb r3, [r0] mov r2, r3, lsr #24 strb r2, [r0, #+3] mov r2, r3, lsr #16 strb r2, [r0, #+2] mov r3, r3, lsr #8 strb r3, [r0, #+1] bx lr testcase here: test/CodeGen/ARM/truncstore-dag-combine.ll This also helps occasionally for X86 and other cases not involving unaligned load/stores. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42954 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-13Add a simple optimization to simplify the input toChris Lattner
truncate and truncstore instructions, based on the knowledge that they don't demand the top bits. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42952 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-10Correct swapped arguments to getConstant.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42824 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-08DAGCombiner support for UDIVREM/SDIVREM and UMUL_LOHI/SMUL_LOHI. Dan Gohman
Check if one of the two results unneeded so see if a simpler operator could bs used. Also check to see if each of the two computations could be simplified if they were split into separate operators. Factor out the code that calls visit() so that it can be used for this purpose. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42759 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-06Reapply 42677.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42692 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-06revert evan's patch until the header is committedChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42686 91177308-0d34-0410-b5e6-96231b3b80d8