GEP offsets have sext_or_trunc semantics. We were already doing
this for the outer-most GEP, but not for the inner ones.
I believe one of the sanitizer buildbot failures was due to this,
but I did not manage to reproduce the issue or come up with a
test case. Usually the problematic case will already be folded
away due to index type canonicalization.
This fixes all the places that hit the new assertion added in
https://github.com/llvm/llvm-project/pull/106524 in tests. That is,
cases where the value passed to the APInt constructor is not an N-bit
signed/unsigned integer, where N is the bit width and signedness is
determined by the isSigned flag.
The fixes either set the correct value for isSigned, set the
implicitTrunc flag, or perform more calculations inside APInt.
Note that the assertion is currently still disabled by default, so this
patch is mostly NFC.
ConstantFolding behaves differently depending on host's `HAS_IEE754_FLOAT128`.
LLVM should not change the behavior depending on host configurations.
This reverts commit 14c7e4a1844904f3db9b2dc93b722925a8c66b27.
(llvmorg-20-init-3262-g14c7e4a18449 and llvmorg-20-init-3498-g001e423ac626)
This is a reland of (#96287). This patch attempts to reduce the reverted
patch's clang compile time by removing #includes of float128.h and
inlining convertToQuad functions instead.
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.
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.
Uses of __float128 in (#94944) should be float128. Although ConstantFoldFP128
is not reliant on HAS_LOGF128, it is only used by conditional code controlled
by HAS_LOGF128, and will cause unused errors on buildbots.
This is a follow up patch from #90611 which folds logl calls in the same
manner as log.f128 calls. logl suffers from the same problem as logf128
of having slow calls to fp128 log functions which can be constant
folded. However, logl is emitted with -fmath-errno and log.f128 is
emitted by -fno-math-errno by certain intrinsics.
Remove support for the icmp and fcmp constant expressions.
This is part of:
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179
As usual, many of the updated tests will no longer test what they were
originally intended to -- this is hard to preserve when constant
expressions get removed, and in many cases just impossible as the
existence of a specific kind of constant expression was the cause of the
issue in the first place.
This is a second attempt to land #84501 which failed on several targets.
This patch adds the HAS_IEE754_FLOAT128 define which makes the check for
typedef'ing float128 more precise by checking whether __uint128_t is
available and checking if the host does not use __ibm128 which is
prevalent on power pc targets and replaces IEEE754 float128s.
This implements the `nusw` and `nuw` flags for `getelementptr` as
proposed at
https://discourse.llvm.org/t/rfc-add-nusw-and-nuw-flags-for-getelementptr/78672.
The three possible flags are encapsulated in the new `GEPNoWrapFlags`
class. Currently this class has a ctor from bool, interpreted as the
InBounds flag. This ctor should be removed in the future, as code gets
migrated to handle all flags.
There are a few places annotated with `TODO(gep_nowrap)`, where I've had
to touch code but opted to not infer or precisely preserve the new
flags, so as to keep this as NFC as possible and make sure any changes
of that kind get test coverage when they are made.
This patch canonicalizes constant expression GEPs to use i8 source
element type, aka ptradd. This is the ConstantFolding equivalent of the
InstCombine canonicalization introduced in #68882.
I believe all our optimizations working on constant expression GEPs
(like GlobalOpt etc) have already been switched to work on offsets, so I
don't expect any significant fallout from this change.
This is part of:
https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699
When calculating the exit count exhaustively, if any of the involved
operations is non-deterministic, the exit count we compute at
compile-time and the exit count at run-time may differ. Using these
non-deterministic constant folding results is only correct if we
actually replace all uses of the instruction with the value. SCEV (or
its consumers) generally don't do this.
Handle this by adding a new AllowNonDeterministic flag to the constant
folding API, and disabling it in SCEV. If non-deterministic results are
not allowed, do not fold FP lib calls in general, and FP operations
returning NaNs in particular. This could be made more precise (some FP
libcalls like fabs are fully deterministic), but I don't think this that
precise handling here is worthwhile.
Fixes the interesting part of
https://github.com/llvm/llvm-project/issues/89885.
Use ICmpInst::compare() where possible, ConstantFoldCompareInstOperands
in other places. This only changes places where the either the fold is
guaranteed to succeed, or the code doesn't use the resulting compare if
we fail to fold.
This is a second attempt to land #84501 which failed on several targets.
This patch adds the HAS_IEE754_FLOAT128 define which makes the check for
typedef'ing float128 more precise by checking whether __uint128_t is available
and checking if the host does not use __ibm128 which is prevalent on power pc
targets and replaces IEEE754 float128s.
This patch enables constant folding for 128 bit floating-point logf
calls. This is achieved by querying if the host system has the logf128()
symbol available with a CMake test. If so, replace the runtime call with
the compile time value returned from logf128.
As part of the migration to ptradd
(https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699),
we need to change the representation of the `inrange` attribute, which
is used for vtable splitting.
Currently, inrange is specified as follows:
```
getelementptr inbounds ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, inrange i32 1, i64 2)
```
The `inrange` is placed on a GEP index, and all accesses must be "in
range" of that index. The new representation is as follows:
```
getelementptr inbounds inrange(-16, 16) ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, i32 1, i64 2)
```
This specifies which offsets are "in range" of the GEP result. The new
representation will continue working when canonicalizing to ptradd
representation:
```
getelementptr inbounds inrange(-16, 16) (i8, ptr @vt, i64 48)
```
The inrange offsets are relative to the return value of the GEP. An
alternative design could make them relative to the source pointer
instead. The result-relative format was chosen on the off-chance that we
want to extend support to non-constant GEPs in the future, in which case
this variant is more expressive.
This implementation "upgrades" the old inrange representation in bitcode
by simply dropping it. This is a very niche feature, and I don't think
trying to upgrade it is worthwhile. Let me know if you disagree.
Teaching ConstantFoldLoadFromUniformValue that types that are padded in
memory can't be considered as uniform.
Using the big hammer to prevent optimizations when loading from a
constant for which DataLayout::typeSizeEqualsStoreSize would return
false.
Main problem solved would be something like this:
store i17 -1, ptr %p, align 4
%v = load i8, ptr %p, align 1
If for example the i17 occupies 32 bits in memory, then LLVM IR doesn't
really tell where the padding goes. And even if we assume that the 15
most significant bits are padding, then they should be considered as
undefined (even if LLVM backend typically would pad with zeroes).
Anyway, for a big-endian target the load would read those most
significant bits, which aren't guaranteed to be one's. So it would be
wrong to constant fold the load as returning -1.
If LLVM IR had been more explicit about the placement of padding, then
we could allow the constant fold of the load in the example, but only
for little-endian.
Fixes: https://github.com/llvm/llvm-project/issues/81793
