Add constant-folding support for the NVVM intrinsics for converting
float/double to signed/unsigned int32/int64 types, including all
rounding-modes and ftz modifiers.
If x is NaN, then fmul (x, 1) may produce a different NaN value.
Our float semantics explicitly permit folding fmul (x, 1) to x, but we
can't do this when we're replacing a select input, as selects are
supposed to preserve the exact bitwise value.
Fixes
https://github.com/llvm/llvm-project/pull/115152#issuecomment-2545773114.
This calls into the existing constant folding for `llvm.sin` and
`llvm.cos`, which currently does not fold for any non-finite values, so
most tests are negative tests at the moment.
Note: The constant folding does not consider the `afn` fast-math flag
and will produce the same result regardless of if the flag is set.
This is a reland of #114527 that updates the syntax of one of the tests
from: `<float 1.000000e+00, float 1.000000e+00>` to `splat (float
1.000000e+00)`.
This calls into the existing constant folding for `llvm.sin` and
`llvm.cos`, which currently does not fold for any non-finite values, so
most tests are negative tests at the moment.
Note: The constant folding does not consider the `afn` fast-math flag
and will produce the same result regardless of if the flag is set.
Calls to `@llvm.abs(undef, i1 true)` and `@llvm.abs(INT_MIN, i1 true)`
can be optimized to `poison` instead of `undef`.
[Alive2](https://alive2.llvm.org/ce/z/Hg-2ug)
InstSimplify currently folds patterns like `(x | y) uge x` and `(x & y)
ule x` to true. However, it cannot handle combinations of such
situations, such as `(x | y) uge (x & z)` etc.
To support this, recursively collect operands of monotonic instructions
(that preserve either a greater-or-equal or less-or-equal relationship)
and then check whether any of them match.
Fixes https://github.com/llvm/llvm-project/issues/69333.
Since cd16b07 (IR: introduce CmpInst::isEquivalence), there is now an
isEquivalence routine in CmpInst that we can use to determine
equivalence in simplifySelectWithICmpEq. Implement this, extending the
code from integer-equalities to integer and floating-point equivalences.
InstSimplify currently folds alloc1 == alloc2 to false, even if one of
them is a zero-size allocation. A zero-size allocation may have the same
address as another allocation.
This also disables the fold for the case where we're comparing a
zero-size alloc with the middle of another allocation. It's possible
that this case is legal to fold depending on our precise zero-size
allocation semantics, but LangRef currently doesn't specify this either
way, so we shouldn't make assumptions here.
The existing logic mostly works with the main changes being:
* Use getScalarSizeInBits instead of IntegerType::getBitWidth
* Use ConstantInt::get(Type* instead of ConstantInt::get(LLVMContext
The two folding operations are causing a cycle for the following case
with
scalable vector types:
define <vscale x 2 x double> @test_fneg_select_abs(<vscale x 2 x i1>
%cond, <vscale x 2 x double> %b) {
%1 = select <vscale x 2 x i1> %cond, <vscale x 2 x double>
zeroinitializer, <vscale x 2 x double> %b
%2 = fneg fast <vscale x 2 x double> %1
ret <vscale x 2 x double> %2
}
1) fold fneg: -(Cond ? C : Y) -> Cond ? -C : -Y
2) fold select: (Cond ? -X : -Y) -> -(Cond ? X : Y)
1) results in the following since '<vscale x 2 x double>
zeroinitializer' passes
the check for the immediate constant:
%.neg = fneg fast <vscale x 2 x double> zeroinitializer
%b.neg = fneg fast <vscale x 2 x double> %b
%1 = select fast <vscale x 2 x i1> %cond, <vscale x 2 x double> %.neg,
<vscale x 2 x double> %b.neg
and so we end up going back and forth between 1) and 2).
Attempt to fold scalable vector constants, so that we end up with a
splat instead:
define <vscale x 2 x double> @test_fneg_select_abs(<vscale x 2 x i1>
%cond, <vscale x 2 x double> %b) {
%b.neg = fneg fast <vscale x 2 x double> %b
%1 = select fast <vscale x 2 x i1> %cond, <vscale x 2 x double>
shufflevector (<vscale x 2 x double> insertelement (<vscale x 2 x
double> poison, double -0.000000e+00, i64 0), <vscale x 2 x double>
poison, <vscale x 2 x i32> zeroinitializer), <vscale x 2 x double>
%b.neg
ret <vscale x 2 x double> %1
}
Reuse llvm::isTriviallyVectorizable in llvm::isNotCrossLaneOperation, in
order to get it to handle more intrinsics.
Alive2 proofs for changed tests: https://alive2.llvm.org/ce/z/XSV_GT
Factor out and unify common code from InstSimplify and InstCombine that
partially guard against cross-lane vector operations into
llvm::isNotCrossLaneOperation in ValueTracking.
Alive2 proofs for changed tests: https://alive2.llvm.org/ce/z/68H4ka
We were missing the signed flag on the negative value, so the
range was incorrectly interpreted for integers larger than 64-bit.
Split out from https://github.com/llvm/llvm-project/pull/80309.
This is a reland of #96287. This change makes tests in logf128.ll ignore
the sign of NaNs for negative value tests and moves an #include <cmath>
to be blocked behind #ifndef _GLIBCXX_MATH_H.
After #98505, the textual IR keyword `x86_mmx` was temporarily made to
parse as `<1 x i64>`, so as not to require a lot of test update noise.
This completes the removal of the type, by removing the`x86_mmx` keyword
from the IR parser, and making the (now no-op) test updates via `sed -i
's/\bx86_mmx\b/<1 x i64>/g' $(git grep -l x86_mmx llvm/test/)`.
Resulting bitcasts from <1 x i64> to itself were then manually deleted.
Changes to llvm/test/Bitcode/compatibility-$VERSION.ll were reverted, as
they're intended to be equivalent to the .bc file, if parsed by old
LLVM, so shouldn't be updated.
A few tests were removed, as they're no longer testing anything, in the
following files:
- llvm/test/Transforms/GlobalOpt/x86_mmx_load.ll
- llvm/test/Transforms/InstCombine/cast.ll
- llvm/test/Transforms/InstSimplify/ConstProp/gep-zeroinit-vector.ll
Works towards issue #98272.
It is now translated to `<1 x i64>`, which allows the removal of a bunch
of special casing.
This _incompatibly_ changes the ABI of any LLVM IR function with
`x86_mmx` arguments or returns: instead of passing in mmx registers,
they will now be passed via integer registers. However, the real-world
incompatibility caused by this is expected to be minimal, because Clang
never uses the x86_mmx type -- it lowers `__m64` to either `<1 x i64>`
or `double`, depending on ABI.
This change does _not_ eliminate the SelectionDAG `MVT::x86mmx` type.
That type simply no longer corresponds to an IR type, and is used only
by MMX intrinsics and inline-asm operands.
Because SelectionDAGBuilder only knows how to generate the
operands/results of intrinsics based on the IR type, it thus now
generates the intrinsics with the type MVT::v1i64, instead of
MVT::x86mmx. We need to fix this before the DAG LegalizeTypes, and thus
have the X86 backend fix them up in DAGCombine. (This may be a
short-lived hack, if all the MMX intrinsics can be removed in upcoming
changes.)
Works towards issue #98272.
The final case in Simplify (where Res == Absorber and the predicate is
inverted) is not generally safe when the simplification is a refinement.
In particular, we may simplify assuming a specific value for undef, but
then chose a different one later.
However, it *is* safe to refine poison in this context, unlike in the
equivalent select folds. This is the reason why this fold did not use
AllowRefinement=false in the first place, and using that option would
introduce a lot of test regressions.
This patch takes the middle path of disabling undef refinements in
particular using the getWithoutUndef() SimplifyQuery option. However,
this option doesn't actually work in this case, because the problematic
fold is inside constant folding, and we currently don't propagate this
option all the way from InstSimplify over ConstantFolding to
ConstantFold. Work around this by explicitly checking for undef operands
in simplifyWithOpReplaced().
Finally, make sure that places where AllowRefinement=false also use
Q.getWithoutUndef(). I don't have a specific test case for this (the
original one does not work because we don't simplify selects with
constant condition in this mode in the first place) but this seems like
the correct thing to do to be conservative.
Fixes https://github.com/llvm/llvm-project/issues/98753.
This patch avoids calling `isKnownNeverNaN` in `simplifyAndOrOfFCmps`
since `fcmp ord/uno X, NNAN` will be canonicalized into `fcmp ord/uno X,
0.0` in InstCombine.
