ptrtoaddr can be handled the same as ptrtoint here. The pointer known
bits cover the full pointer width, and ptrtoaddr either passes those
through directly or truncates to the address size.
This partially reverts commit 108a22ed5fa1836b4cfcd05e9d96f98a533068d5.
Restore the sign-bit tracking for both inputs known-negative case,
and leave the 0 handling for later. There is a libc test improperly
relying on running code compiled for IEEE behavior that changed
the output denormal mode.
Reverts llvm/llvm-project#174123
This caused test failures within LLVM libc. They can be reproduced by
doing a libc build against a clang with this commit included and running
`ninja -k 0 libc.test.src.math.smoke.log1p_test.__unit__
libc.test.src.math.smoke.log1p_test.__unit__.__NO_FMA_OPT`.
This already recognized that if both inputs are positive, the
result is positive. Extend this to the mirror situation with
negative inputs.
Also special case fadd x, x. Canonically, fmul x, 2 is fadd x, x.
We can tell the sign bit won't change, and 0 will propagate.
I'm working on optimizing out the tail sequences in the
implementations of the 4 different flavors of pow. These
include chains of selects on the various edge cases.
Related to #64870
Improve known non-nan sign bit tracking. Handle cases with
a known 0 or inf input of indeterminate sign.
The tails of some library functions have sign management
for special cases.
Add support for ptrtoaddr in isKnownNonZero(). We can directly forward
to isKnownNonZero() for the pointer here, as we define nonnull as
applying to the address bits.
Also adjust the ptrtoint implementation to match, by requiring that the
result type >= address size (rather than >= pointer size). This is just
for clarity, in practice this is a non-canonical form.
Currently these intrinsics output `undef` on poison, which triggers CI
errors on PRs that want to add poison tests for funnel shifts (such as
#172723). Let's make `fshl` and `fshr` propagate poison instead.
Multiply by large constant can be used to scale denormal inputs into
a normal range. This pattern appears frequently in math function library
implementations to make use of hardware instructions that do not support
denormals. We already handle this case for ldexp, but now canonicalize
ldexp by a constant to an fmul.
The test cases are mostly the existing nofpclass test for ldexp,
run through the new instcombine to replace ldexp with fmul.
Changed the range computation in computeOverflowForUnsignedMul to use
computeConstantRange as well.
This expands the patterns that InstCombine manages to narrow a mul that
has values that come from zext, for example if a value comes from a div
operation then the known bits doesn't give the narrowest possible range
for that value.
---------
Co-authored-by: Adar Dagan <adar.dagan@mobileye.com>
Only check up to CtxI (CtxIter) when checking for calls that may free
in CtxI's block.
Missed update in https://github.com/llvm/llvm-project/pull/167965.
This should be NFC, as all current callers pass a terminator that is
guaranteed to not free as CtxI
In https://github.com/llvm/llvm-project/pull/165748 constant expressions
were allowed in `collectPossibleValues` because we are still using
insertelement + shufflevector idioms to represent a scalable vector
splat. However, it also accepts some unresolved constants like ptrtoint
of globals or pointer difference between two globals. Absolutely we can
ask the user to check this case with the constant folding API. However,
since we don't observe the real-world usefulness of handling constant
expressions, I decide to be more conservative and only handle immediate
constants in the helper function. With this patch, we don't need to
touch the SimplifyCFG part, as the values can only be either ConstantInt
or undef/poison values (NB: switch on undef condition is UB).
Fix the miscompilation reported by
https://github.com/llvm/llvm-project/pull/165748#issuecomment-3532245218
Extend willNotFreeBetween to perform simple checking across blocks to
support the case where CtxI is in a successor of the block that contains
the assume, but the assume's parent is the single predecessor of CtxI's
block.
This enables using _builtin_assume_dereferenceable to vectorize
std::find_if and co in practice.
End-to-end reproducer: https://godbolt.org/z/6jbsd4EjT
PR: https://github.com/llvm/llvm-project/pull/167965
In this patch, we try to detect the lerp pattern: a * (b - c) + c * d
where a >= 0, b >= 0, c >= 0, d >= 0, and b >= c.
In that particular case, we can use the following chain of reasoning:
a * (b - c) + c * d <= a' * (b - c) + a' * c = a' * b where a' = max(a,
d)
Since that is true for arbitrary a, b, c and d within our constraints,
we can
conclude that:
max(a * (b - c) + c * d) <= max(max(a), max(d)) * max(b) = U
Considering that any result of the lerp would be less or equal to U, it
would
have at least the number of leading 0s as in U.
While being quite a specific situation, it is fairly common in computer
graphics in the shape of alpha blending.
In conjunction with #165877, increases vectorization factor for lerp
loops.
Also add a corresponding intrinsic property that can be used to mark
intrinsics that do not introduce poison, for example simple arithmetic
intrinsics that propagate poison just like a simple arithmetic
instruction.
As a smoke test this patch adds the new property to
llvm.amdgcn.fmul.legacy.
Add support for the new maximumnum and minimumnum intrinsics in various
optimizations in InstSimplify.
Also, change the behavior of optimizing maxnum(sNaN, x) to simplify to
qNaN instead of x to better match the LLVM IR spec, and add more tests
for sNaN behavior for all 3 max/min intrinsic types.
When using information from dereferenceable assumptions, we need to make
sure that the memory is not freed between the assume and the specified
context instruction. Instead of just checking canBeFreed, check if there
any calls that may free between the assume and the context instruction.
This patch introduces a willNotFreeBetween to check for calls that may
free between an assume and a context instructions, to also be used in
https://github.com/llvm/llvm-project/pull/161255.
PR: https://github.com/llvm/llvm-project/pull/161725
A common idiom is the usage of the PatternMatch match function within a
functional algorithm like all_of. Introduce a match functor to shorten
this idiom.
Co-authored-by: Luke Lau <luke@igalia.com>
Fixes an issue where bits next to the sign bit were not constant-folded
when squaring a sign- or zero-extended small integer. Added logic to
detect when both operands of a multiplication are the same extended
value, allowing InstCombine to mark bits above the maximum possible
square as known zero. This enables correct folding of (x * x) & (1 << N)
to 0 when N is out of range.
Proof: https://alive2.llvm.org/ce/z/YGou44Fixes#152061
We just replaced SmallSet<T *, N> with SmallPtrSet<T *, N>, bypassing
the redirection found in SmallSet.h. With that, we no longer need to
include SmallSet.h in many files.
This makes the optimization in optimizeStringLength for strlen(gep
@glob, %x) -> sub endof@glob, %x a little more resilient, and maybe a
bit more correct for geps with non-array types.
This patch replaces SmallSet<T *, N> with SmallPtrSet<T *, N>. Note
that SmallSet.h "redirects" SmallSet to SmallPtrSet for pointer
element types:
template <typename PointeeType, unsigned N>
class SmallSet<PointeeType*, N> : public SmallPtrSet<PointeeType*, N>
{};
We only have 140 instances that rely on this "redirection", with the
vast majority of them under llvm/. Since relying on the redirection
doesn't improve readability, this patch replaces SmallSet with
SmallPtrSet for pointer element types.
When InstTy is a type like IntrinsicInst which can have a variable
number of arguments, we can encounter a case where Operation will have
fewer than two arguments and error at the getOperand() calls.
Fixes: https://github.com/llvm/llvm-project/issues/152725.
