As shown in the code comment, we don't need all of 'fast',
but we do need reassoc + nsz + nnan.
Differential Revision: https://reviews.llvm.org/D43765
llvm-svn: 327796
This matcher implementation appears to be slightly more efficient than
the generic constant check that it is replacing because every use was
for matching FP patterns, but the previous code would check int and
pointer type nulls too.
llvm-svn: 327627
From the LangRef definition for frem:
"The value produced is the floating-point remainder of the two operands.
This is the same output as a libm ‘fmod‘ function, but without any
possibility of setting errno. The remainder has the same sign as the
dividend. This instruction is assumed to execute in the default
floating-point environment."
llvm-svn: 327626
As shown in:
https://bugs.llvm.org/show_bug.cgi?id=27151
...the existing fold could miscompile when X is NaN.
The fold was also dependent on 'ninf' but that's not necessary.
From IEEE-754 (with default rounding which we can assume for these opcodes):
"When the sum of two operands with opposite signs (or the difference of two
operands with like signs) is exactly zero, the sign of that sum (or difference)
shall be +0...However, x + x = x − (−x) retains the same sign as x even when
x is zero."
llvm-svn: 327575
The 'hasOneUse' check is a giveaway that something's not right.
We never need to check that in InstSimplify because we don't
create new instructions here.
These are all handled as icmp simplifies which then trigger
existing select simplifies, so there's no need to duplicate
a composite fold of the two.
llvm-svn: 326750
This is NFC for the moment (and independent of any potential NaN semantic
controversy). Besides making the code in InstSimplify easier to read, the
motivation is to eventually allow undef elements in vector constants to
match too. A proposal to add the base logic for that is in D43792.
llvm-svn: 326600
Loosening the matcher definition reveals a subtle bug in InstSimplify (we should not
assume that because an operand constant matches that it's safe to return it as a result).
So I'm making that change here too (that diff could be independent, but I'm not sure how
to reveal it before the matcher change).
This also seems like a good reason to *not* include matchers that capture the value.
We don't want to encourage the potential misstep of propagating undef values when it's
not allowed/intended.
I didn't include the capture variant option here or in the related rL325437 (m_One),
but it already exists for other constant matchers.
llvm-svn: 325466
Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.
Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html
I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.
Differential Revision: https://reviews.llvm.org/D42123
llvm-svn: 325102
These intrinsic folds were added with D41381, but only allowed with isFast().
That's more than necessary because FMF has 'reassoc' to apply to these
kinds of folds after D39304, and that's all we need in these cases.
Differential Revision: https://reviews.llvm.org/D43160
llvm-svn: 324967
Summary:
If any vector divisor element is undef, we can arbitrarily choose it be
zero which would make the div/rem an undef value by definition.
Reviewers: spatel, reames
Reviewed By: spatel
Subscribers: magabari, llvm-commits
Differential Revision: https://reviews.llvm.org/D42485
llvm-svn: 323343
This doesn't handle the more complicated case in the bug report yet:
https://bugs.llvm.org/show_bug.cgi?id=35790
For that, we have to match / look through a cast.
llvm-svn: 322327
In one case, we were handling out of bounds, but not undef indices. In the other, we were handling undef (with the comment making the analogy to out of bounds), but not out of bounds. Be consistent and treat both undef and constant out of bounds indices as producing undefined results.
As a side effect, this also protects instcombine from having to handle large constant indices as we always simplify first.
llvm-svn: 321575
Most of the -Wsign-compare warnings are due to the fact that
enums are signed by default in the MS ABI, while the
tautological comparison warnings trigger on x86 builds where
sizeof(size_t) is 4 bytes, so N > numeric_limits<unsigned>::max()
is always false.
Differential Revision: https://reviews.llvm.org/D41256
llvm-svn: 320750
Summary:
An undef extract index can be arbitrarily chosen to be an
out-of-range index value, which would result in the instruction being undef.
This change closes a gap identified while working on lowering vector permute intrinsics
with variable index vectors to pure LLVM IR.
Reviewers: arsenm, spatel, majnemer
Reviewed By: arsenm, spatel
Subscribers: fhahn, nhaehnle, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D40231
llvm-svn: 319910
The 'ord' and 'uno' predicates have a logic operation for NAN built into their definitions:
FCMP_ORD = 7, ///< 0 1 1 1 True if ordered (no nans)
FCMP_UNO = 8, ///< 1 0 0 0 True if unordered: isnan(X) | isnan(Y)
So we can simplify patterns like this:
(fcmp ord (known NNAN), X) && (fcmp ord X, Y) --> fcmp ord X, Y
(fcmp uno (known NNAN), X) || (fcmp uno X, Y) --> fcmp uno X, Y
It might be better to split this into (X uno 0) | (Y uno 0) as a canonicalization, but that
would be another patch.
Differential Revision: https://reviews.llvm.org/D40130
llvm-svn: 318627
Call ConstantFoldSelectInstruction() to fold cases like below
select <2 x i1><i1 true, i1 false>, <2 x i8> <i8 0, i8 1>, <2 x i8> <i8 2, i8 3>
All operands are constants and the condition has mixed true and false conditions.
Differential Revision: https://reviews.llvm.org/D38369
llvm-svn: 314741
This should bring signed div/rem analysis up to the same level as unsigned.
We use icmp simplification to determine when the divisor is known greater than the dividend.
Each positive test is followed by a negative test to show that we're not overstepping the boundaries of the known bits.
There are extra tests for the signed-min-value special cases.
Alive proofs:
http://rise4fun.com/Alive/WI5
Differential Revision: https://reviews.llvm.org/D37713
llvm-svn: 313264
The idea to make an 'isDivZero' helper was suggested for the signed case in D37713:
https://reviews.llvm.org/D37713
This clean-up makes it clear that D37713 is just filling the gap for signed div/rem,
removes unnecessary code, and allows us to remove a bit of duplicated code from the
planned improvement in D37713.
llvm-svn: 313261
I'm trying to refactor some shared code for integer div/rem,
but I keep having to scroll through fdiv. The FP ops have
nothing in common with the integer ops, so I'm moving FP
below everything else.
While here, improve a couple of comments and fix some formatting.
llvm-svn: 312913
This removes some duplicated code and makes it easier to support signed div/rem
in a similar way if we want to do that. Note that the existing comments were not
accurate - we don't need a constant divisor to simplify; icmp simplification does
more than that. But as the added tests show, it could go even further.
llvm-svn: 312885
It now knows the tricks of both functions.
Also, fix a bug that considered allocas of non-zero address space to be always non null
Differential Revision: https://reviews.llvm.org/D37628
llvm-svn: 312869
This patch teaches decomposeBitTestICmp to look through truncate instructions on the input to the compare. If a truncate is found it will now return the pre-truncated Value and appropriately extend the APInt mask.
This allows some code to be removed from InstSimplify that was doing this functionality.
This allows InstCombine's bit test combining code to match a pre-truncate Value with the same Value appear with an 'and' on another icmp. Or it allows us to combine a truncate to i16 and a truncate to i8. This also required removing the type check from the beginning of getMaskedTypeForICmpPair, but I believe that's ok because we still have to find two values from the input to each icmp that are equal before we'll do any transformation. So the type check was really just serving as an early out.
There was one user of decomposeBitTestICmp that didn't want to look through truncates, so I've added a flag to prevent that behavior when necessary.
Differential Revision: https://reviews.llvm.org/D37158
llvm-svn: 312382
This recommits r310869, with the moved files and no extra changes.
Original commit message:
This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.
I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.
I also had to make decomposeBitTest support vectors since InstSimplify needs that.
As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.
Differential Revision: https://reviews.llvm.org/D36593
llvm-svn: 310889
Failed to add the two files that moved. And then added an extra change I didn't mean to while trying to fix that. Reverting everything.
llvm-svn: 310873
