While we can form the @llvm.mul.with.overflow easily,
we are still left with that check that was guarding against div-by-0.
And in the second case we won't even flatten the CFG.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366747 91177308-0d34-0410-b5e6-96231b3b80d8
Liveness analysis abstract attribute used to indicate which BasicBlocks are dead and can therefore be ignored.
Right now we are only looking at noreturn calls.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential revision: https://reviews.llvm.org/D64162
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366736 91177308-0d34-0410-b5e6-96231b3b80d8
Porting function return value attribute noalias to attributor.
This will be followed with a patch for callsite and function argumets.
Reviewers: jdoerfert
Subscribers: lebedev.ri, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D63067
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366728 91177308-0d34-0410-b5e6-96231b3b80d8
While debugging code that uses SafeStack, we've noticed that LLVM
produces an invalid DWARF. Concretely, in the following example:
int main(int argc, char* argv[]) {
std::string value = "";
printf("%s\n", value.c_str());
return 0;
}
DWARF would describe the value variable as being located at:
DW_OP_breg14 R14+0, DW_OP_deref, DW_OP_constu 0x20, DW_OP_minus
The assembly to get this variable is:
leaq -32(%r14), %rbx
The order of operations in the DWARF symbols is incorrect in this case.
Specifically, the deref is incorrect; this appears to be incorrectly
re-inserted in repalceOneDbgValueForAlloca.
With this change which inserts the deref after the offset instead of
before it, LLVM produces correct DWARF:
DW_OP_breg14 R14-32
Differential Revision: https://reviews.llvm.org/D64971
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366726 91177308-0d34-0410-b5e6-96231b3b80d8
The bytes inserted before an overaligned global need to be padded according
to the alignment set on the original global in order for the initializer
to meet the global's alignment requirements. The previous implementation
that padded to the pointer width happened to be correct for vtables on most
platforms but may do the wrong thing if the vtable has a larger alignment.
This issue is visible with a prototype implementation of HWASAN for globals,
which will overalign all globals including vtables to 16 bytes.
There is also no padding requirement for the bytes inserted after the global
because they are never read from nor are they significant for alignment
purposes, so stop inserting padding there.
Differential Revision: https://reviews.llvm.org/D65031
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366725 91177308-0d34-0410-b5e6-96231b3b80d8
We were previously ignoring alignment entirely when combining globals
together in this pass. There are two main things that we need to do here:
add additional padding before each global to meet the alignment requirements,
and set the combined global's alignment to the maximum of all of the original
globals' alignments.
Since we now need to calculate layout as we go anyway, use the calculated
layout to produce GlobalLayout instead of using StructLayout.
Differential Revision: https://reviews.llvm.org/D65033
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366722 91177308-0d34-0410-b5e6-96231b3b80d8
Current algorithm to update branch weights of latch block and its copies is
based on the assumption that number of peeling iterations is approximately equal
to trip count.
However it is not correct. According to profitability check in one case we can decide to peel
in case it helps to reduce the number of phi nodes. In this case the number of peeled iteration
can be less then estimated trip count.
This patch introduces another way to set the branch weights to peeled of branches.
Let F is a weight of the edge from latch to header.
Let E is a weight of the edge from latch to exit.
F/(F+E) is a probability to go to loop and E/(F+E) is a probability to go to exit.
Then, Estimated TripCount = F / E.
For I-th (counting from 0) peeled off iteration we set the the weights for
the peeled latch as (TC - I, 1). It gives us reasonable distribution,
The probability to go to exit 1/(TC-I) increases. At the same time
the estimated trip count of remaining loop reduces by I.
As a result after peeling off N iteration the weights will be
(F - N * E, E) and trip count of loop becomes
F / E - N or TC - N.
The idea is taken from the review of the patch D63918 proposed by Philip.
Reviewers: reames, mkuper, iajbar, fhahn
Reviewed By: reames
Subscribers: hiraditya, zzheng, llvm-commits
Differential Revision: https://reviews.llvm.org/D64235
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366665 91177308-0d34-0410-b5e6-96231b3b80d8
icmp ne %x, INT_MIN can be treated similarly to icmp sgt %x, INT_MIN.
icmp ne %x, INT_MAX can be treated similarly to icmp slt %x, INT_MAX.
icmp ne %x, UINT_MAX can be treated similarly to icmp ult %x, UINT_MAX.
We already treat icmp ne %x, 0 similarly to icmp ugt %x, 0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366662 91177308-0d34-0410-b5e6-96231b3b80d8
If the blockaddress is not destoryed, the destination block will still
be marked as having its address taken, limiting further transformations.
I think there are other places where the dead blockaddress constants are kept
around, I'll look into that as follow up.
Reviewers: craig.topper, brzycki, davide
Reviewed By: brzycki, davide
Differential Revision: https://reviews.llvm.org/D64936
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366633 91177308-0d34-0410-b5e6-96231b3b80d8
If the legality check is `(shiftNbits-maskNbits) s>= 0`,
then we can simplify it to `shiftNbits u>= maskNbits`,
which is easier to check for.
However, currently switching the `dropRedundantMaskingOfLeftShiftInput()`
to `SimplifyICmpInst()` does not catch these cases and regresses
currently-handled cases, so i'll leave it as is for now.
https://rise4fun.com/Alive/25P
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366564 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
f. `((x << MaskShAmt) a>> MaskShAmt) << ShiftShAmt`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
f. `(ShiftShAmt-MaskShAmt) s>= 0` (i.e. `ShiftShAmt u>= MaskShAmt`)
Normally, the inner pattern is sign-extend,
but for our purposes it's no different to other patterns:
alive proofs:
f: https://rise4fun.com/Alive/7U3
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Differential Revision: https://reviews.llvm.org/D64524
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366540 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
e. `((x << MaskShAmt) l>> MaskShAmt) << ShiftShAmt`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
e. `(ShiftShAmt-MaskShAmt) s>= 0` (i.e. `ShiftShAmt u>= MaskShAmt`)
alive proofs:
e: https://rise4fun.com/Alive/0FT
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Differential Revision: https://reviews.llvm.org/D64521
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366539 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
d. `(x & ((-1 << MaskShAmt) >> MaskShAmt)) << ShiftShAmt`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
d. `(ShiftShAmt-MaskShAmt) s>= 0` (i.e. `ShiftShAmt u>= MaskShAmt`)
alive proofs:
d: https://rise4fun.com/Alive/I5Y
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Differential Revision: https://reviews.llvm.org/D64519
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366538 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
c. `(x & (-1 >> MaskShAmt)) << ShiftShAmt`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
c. `(ShiftShAmt-MaskShAmt) s>= 0` (i.e. `ShiftShAmt u>= MaskShAmt`)
alive proofs:
c: https://rise4fun.com/Alive/RgJh
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Differential Revision: https://reviews.llvm.org/D64517
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366537 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
b. `(x & (~(-1 << maskNbits))) << shiftNbits`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
b. `(MaskShAmt+ShiftShAmt) u>= bitwidth(x)`
alive proof:
b: https://rise4fun.com/Alive/y8M
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Differential Revision: https://reviews.llvm.org/D64514
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366536 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If we have some pattern that leaves only some low bits set, and then performs
left-shift of those bits, if none of the bits that are left after the final
shift are modified by the mask, we can omit the mask.
There are many variants to this pattern:
a. `(x & ((1 << MaskShAmt) - 1)) << ShiftShAmt`
All these patterns can be simplified to just:
`x << ShiftShAmt`
iff:
a. `(MaskShAmt+ShiftShAmt) u>= bitwidth(x)`
alive proof:
a: https://rise4fun.com/Alive/wi9
Indeed, not all of these patterns are canonical.
But since this fold will only produce a single instruction
i'm really interested in handling even uncanonical patterns,
since i have this general kind of pattern in hotpaths,
and it is not totally outlandish for bit-twiddling code.
For now let's start with patterns where both shift amounts are variable,
with trivial constant "offset" between them, since i believe this is
both simplest to handle and i think this is most common.
But again, there are likely other variants where we could use
ValueTracking/ConstantRange to handle more cases.
https://bugs.llvm.org/show_bug.cgi?id=42563
Reviewers: spatel, nikic, huihuiz, xbolva00
Reviewed By: xbolva00
Subscribers: efriedma, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64512
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366535 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
- As the pointer stripping now tracks through `addrspacecast`, prepare
to handle the bit-width difference from the result pointer.
Reviewers: jdoerfert
Subscribers: jvesely, nhaehnle, hiraditya, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64928
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366470 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Since the target has no significant advantage of vectorization,
vector instructions bous threshold bonus should be optional.
amdgpu-inline-arg-alloca-cost parameter default value and the target
InliningThresholdMultiplier value tuned then respectively.
Reviewers: arsenm, rampitec
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, eraman, hiraditya, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64642
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366348 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Deduce the "willreturn" attribute for functions.
For now, intrinsics are not willreturn. More annotation will be done in another patch.
Reviewers: jdoerfert
Subscribers: jvesely, nhaehnle, nicholas, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63046
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366335 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
- As the pointer stripping could trace through `addrspacecast` now, need
to sext/trunc the offset to ensure it has the same width as the
pointer after stripping.
Reviewers: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64768
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366162 91177308-0d34-0410-b5e6-96231b3b80d8
As there are some reported miscompiles with AVX512 and performance regressions
in Eigen. Verified with the original committer and testcases will be forthcoming.
This reverts commit r364964.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366154 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
There is currently a correctness issue when unrolling loops containing
callbr's where their indirect targets are being updated correctly to the
newly created labels, but their operands are not. This manifests in
unrolled loops where the second and subsequent copies of callbr
instructions have blockaddresses of the label from the first instance of
the unrolled loop, which would result in nonsensical runtime control
flow.
For now, conservatively do not unroll the loop. In the future, I think
we can pursue unrolling such loops provided we transform the cloned
callbr's operands correctly.
Such a transform and its legalities are being discussed in:
https://reviews.llvm.org/D64101
Link: https://bugs.llvm.org/show_bug.cgi?id=42489
Link: https://groups.google.com/forum/#!topic/clang-built-linux/z-hRWP9KqPI
Reviewers: fhahn, hfinkel, efriedma
Reviewed By: fhahn, hfinkel, efriedma
Subscribers: efriedma, hiraditya, zzheng, dmgreen, llvm-commits, pirama, kees, nathanchance, E5ten, craig.topper, chandlerc, glider, void, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64368
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366130 91177308-0d34-0410-b5e6-96231b3b80d8
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.
It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.
The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.
Reviewers: pcc, hctim, vitalybuka, ostannard
Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64169
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366123 91177308-0d34-0410-b5e6-96231b3b80d8
There are scenarios where mutually recursive functions may cause the SCC
to contain both read only and write only functions. This removes an
assertion when adding read attributes which caused a crash with a the
provided test case, and instead just doesn't add the attributes.
Patch by Luke Lau <luke.lau@intel.com>
Differential Revision: https://reviews.llvm.org/D60761
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366090 91177308-0d34-0410-b5e6-96231b3b80d8
It is possible that loop exit has two predecessors in a loop body.
In this case after the peeling the iDom of the exit should be a clone of
iDom of original exit but no a clone of a block coming to this exit.
Reviewers: reames, fhahn
Reviewed By: reames
Subscribers: hiraditya, zzheng, llvm-commits
Differential Revision: https://reviews.llvm.org/D64618
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366050 91177308-0d34-0410-b5e6-96231b3b80d8
We do not compute the scalarization overhead in getVectorIntrinsicCost
and TTI::getIntrinsicInstrCost requires the full arguments list.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366049 91177308-0d34-0410-b5e6-96231b3b80d8
This CL enables peeling of the loop with multiple exits where
one exit should be from latch and others are basic blocks with
call to deopt.
The peeling is enabled under the flag which is false by default.
Reviewers: reames, mkuper, iajbar, fhahn
Reviewed By: reames
Subscribers: xbolva00, hiraditya, zzheng, llvm-commits
Differential Revision: https://reviews.llvm.org/D63923
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366048 91177308-0d34-0410-b5e6-96231b3b80d8
Loop invariant operands do not need to be scalarized, as we are using
the values outside the loop. We should ignore them when computing the
scalarization overhead.
Fixes PR41294
Reviewers: hsaito, rengolin, dcaballe, Ayal
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D59995
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366030 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit rL365999 / 0f6148df23edcd3081f5e761de19edd4f823f16d.
The tests already exist in this file, and the hoped-for transform
(mentioned in D62871) is invalid because of undef as discussed in
D63060.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366000 91177308-0d34-0410-b5e6-96231b3b80d8
Continue in the spirit of D63618, and use exit count reasoning to prove away loop exits which can not be taken since the backedge taken count of the loop as a whole is provably less than the minimal BE count required to take this particular loop exit.
As demonstrated in the newly added tests, this triggers in a number of cases where IndVars was previously unable to discharge obviously redundant exit tests. And some not so obvious ones.
Differential Revision: https://reviews.llvm.org/D63733
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365920 91177308-0d34-0410-b5e6-96231b3b80d8
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.
Reviewers: jdoerfert, jfb, nhaehnle, arsenm
Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D62766
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365830 91177308-0d34-0410-b5e6-96231b3b80d8
Roman Lebedev