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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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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
2007-10-06Added DAG xforms. e.g.Evan Cheng
(vextract (v4f32 s2v (f32 load $addr)), 0) -> (f32 load $addr) (vextract (v4i32 bc (v4f32 s2v (f32 load $addr))), 0) -> (i32 load $addr) Remove x86 specific patterns. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42677 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-18Fix a bogus splat xform:Evan Cheng
shuffle <undef, undef, x, undef>, <undef, undef, undef, undef>, <2, 2, 2, 2> != <undef, undef, x, undef> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42111 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-18Prevent crash on long double.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42103 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-12Revise previous patch per review comments.Dale Johannesen
Next round of x87 long double stuff. Getting close now, basically works. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41875 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-11Add APInt interfaces to APFloat (allows directlyDale Johannesen
access to bits). Use them in place of float and double interfaces where appropriate. First bits of x86 long double constants handling (untested, probably does not work). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41858 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-10Emit:Chris Lattner
cmpl %eax, %ecx setae %al movzbl %al, %eax instead of: cmpl %eax, %ecx setb %al xorb $1, %al movzbl %al, %eax when using logical not of a C comparison. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41807 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-31Add mod, copysign, abs operations to APFloat.Dale Johannesen
Implement some constant folding in SelectionDAG and DAGCombiner using APFloat. Remove double versions of constructor and getValue from ConstantFPSDNode. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41664 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-27Make DAGCombiner's global alias analysis query more precise in the caseDan Gohman
where both pointers have non-zero offsets. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41491 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-26Revise per review comments.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41409 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-25Add APFloat interface to ConstantFPSDNode. ChangeDale Johannesen
over uses in DAGCombiner. Fix interfaces to work with APFloats. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41407 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-18Fold C ? 0 : 1 to ~C or zext(~C) or trunc(~C) depending the types.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41163 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-26Fix the alias analysis query in DAGCombiner to not add in twoDan Gohman
offsets. The SrcValueOffset values are the real offsets from the SrcValue base pointers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40534 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-13Don't call SimplifyVBinOp for non-vector operations, following earlier reviewDan Gohman
feedback. This theoretically makes the common (scalar) case more efficient. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39823 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-10Fix a bug in the folding of binary operators to undef.Dan Gohman
Thanks to Lauro for spotting this! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38491 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-10Fix the folding of undef in several binary operators to recognizeDan Gohman
undef in either the left or right operand. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38489 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-09Preserve volatililty and alignment information when lowering orDan Gohman
simplifying loads and stores. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38473 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-09Fix this warning:Chris Lattner
DAGCombiner.cpp: In member function 'llvm::SDOperand<unnamed>::DAGCombiner::visitOR(llvm::SDNode*)': DAGCombiner.cpp:1608: warning: passing negative value '-0x00000000000000001' for argument 1 to 'llvm::SDOperand llvm::SelectionDAG::getConstant(uint64_t, llvm::MVT::ValueType, bool)' oiy. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38458 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-03Fix several over-aggressive folds for undef nodes in dagcombine, toDan Gohman
follow the rules for undef used in instcombine. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37851 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-02Teach GetNegatedExpression to negate 0-B to B in UnsafeFPMath mode, andDan Gohman
visitFSUB to fold 0-B to -B in UnsafeFPMath mode. Also change visitFNEG to use isNegatibleForFree/GetNegatedExpression instead of doing a subset of the same thing manually. This fixes test/CodeGen/X86/negative-sin.ll. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37842 91177308-0d34-0410-b5e6-96231b3b80d8
2007-06-25Generalize MVT::ValueType and associated functions to be able to representDan Gohman
extended vector types. Remove the special SDNode opcodes used for pre-legalize vector operations, and the special MVT::Vector type used with them. Adjust lowering and legalize to work with the normal SDNode kinds instead, and to use the normal MVT functions to work with vector types instead of using the two special operands that the pre-legalize nodes held. This allows pre-legalize and post-legalize DAGs, and the code that operates on them, to be more consistent. Pre-legalize vector operators can be handled more consistently with scalar operators. And, -view-dag-combine1-dags and -view-legalize-dags now look prettier for vector code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37719 91177308-0d34-0410-b5e6-96231b3b80d8
2007-06-22Move ComputeMaskedBits, MaskedValueIsZero, and ComputeNumSignBits fromDan Gohman
TargetLowering to SelectionDAG so that they have more convenient access to the current DAG, in preparation for the ValueType routines being changed from standalone functions to members of SelectionDAG for the pre-legalize vector type changes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37704 91177308-0d34-0410-b5e6-96231b3b80d8
2007-06-21Xforms:Evan Cheng
(add (select cc, 0, c), x) -> (select cc, x, (add, x, c)) (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c)) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37685 91177308-0d34-0410-b5e6-96231b3b80d8
2007-06-19Pass a SelectionDAG into SDNode::dump everywhere it's used, in preprationDan Gohman
for needing the DAG node to print pre-legalize extended value types, and to get better debug messages with target-specific nodes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37656 91177308-0d34-0410-b5e6-96231b3b80d8
2007-06-14Rename MVT::getVectorBaseType to MVT::getVectorElementType.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37579 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-25tighten up recursion depth againChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37330 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-24Fix a typo that caused combiner to create mal-formed pre-indexed store where ↵Evan Cheng
value store is the same as the base pointer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37318 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-23prevent exponential recursion in isNegatibleForFreeChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37310 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-18Qualify calls to getTypeForValueType with MVT:: too.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37233 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-16Don't fold bitconvert(load) for preinc/postdec loads. Likewise stores.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37130 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-16Use a ptr set instead of a linear search to unique TokenFactor operands.Chris Lattner
This fixes PR1423 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37102 91177308-0d34-0410-b5e6-96231b3b80d8