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_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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44649 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43944 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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is used, try simplify it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43888 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43511 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43470 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43189 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43160 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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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
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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
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42824 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42692 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42686 91177308-0d34-0410-b5e6-96231b3b80d8
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(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
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42103 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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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
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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
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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
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where both pointers have non-zero offsets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41491 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41409 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41163 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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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
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Thanks to Lauro for spotting this!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38491 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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simplifying loads and stores.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38473 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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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
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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
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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
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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
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(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
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37579 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37330 91177308-0d34-0410-b5e6-96231b3b80d8
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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
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37233 91177308-0d34-0410-b5e6-96231b3b80d8
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37130 91177308-0d34-0410-b5e6-96231b3b80d8
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This fixes PR1423
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37102 91177308-0d34-0410-b5e6-96231b3b80d8
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