Summary:
This "pass" eagerly creates div and rem instructions even when only one
is needed -- it relies on a later pass (machine DCE?) to clean them up.
This is problematic not just from a cleanliness perspective (this pass
is running during CodeGenPrepare, so should leave the IR in a better
state), but it also creates a problem for instruction selection. If we
always have a div+rem, isel will always select a divrem instruction (if
possible), even when a single div or rem would do.
Specifically, in NVPTX, we want to compute rem from the output of div,
if available. But if a div is not available, we want to leave the rem
alone. This transformation is overeager if div is always available.
Because this code runs as part of CodeGenPrepare, it's nontrivial to
write a test for this change. But this will effectively be tested by
a later patch which adds the aforementioned change to NVPTX isel.
Reviewers: tra
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285460 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In BypassSlowDivision's short-dividend path, we would create e.g.
udiv exact i32 %a, %b
"exact" here means that we are asserting that %a is a multiple of %b.
But we have no reason to believe this must be true -- this is just a
bug, as far as I can tell.
Reviewers: tra
Subscribers: jholewinski, llvm-commits
Differential Revision: https://reviews.llvm.org/D26097
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285459 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch introduces updateDiscriminator to DILocation so that it can be directly called by AddDiscriminator. It also makes it easier to update the discriminator later.
Reviewers: dnovillo, dblaikie, aprantl, echristo
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D25959
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285207 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a new function to DebugInfo.cpp that takes an llvm::Module
as input and removes all debug info metadata that is not directly
needed for line tables, thus effectively stripping all type and
variable information from the module.
The primary motivation for this feature was the bitcode work flow
(cf. http://lists.llvm.org/pipermail/llvm-dev/2016-June/100643.html
for more background). This is not wired up yet, but will be in
subsequent patches. For testing, the new functionality is exposed to
opt with a -strip-nonlinetable-debuginfo option.
The secondary use-case (and one that works right now!) is as a
reduction pass in bugpoint. I added two new bugpoint options
(-disable-strip-debuginfo and -disable-strip-debug-types) to control
the new features. By default it will first attempt to remove all debug
information, then only the type info, and then proceed to hack at any
remaining MDNodes.
Thanks to Adrian Prantl for stewarding this patch!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285094 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bug in the handling of lexical scopes, when more than one
scope is defined on the same line or functions are inlined into call
sites that are on the same line as the function definition. This
situation can easily happen in macro expansions.
The problem is solved by introducing a SmallDenseMap<DIScope *,
DILexicalBlockFile *, 1> that keeps track of all the different lexical
scopes that share a line/file location.
Fixes PR30681.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284998 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Utility pass to remove gc.relocates created by rewrite statepoints for GC.
With respect to safepoint verification, the IR generated would be incorrect, and cannot run
as such.
This would be a single transformation on the final optimized IR.
The benefit of the pass is for easy analysis when the IRs are 'polluted' by too
many gc.relocates.
Added tests.
test run: All RS4GC tests with -verify option. Local downstream tests on large
IR files. This also works when the pointer being gc.relocated is another
gc.relocate.
Reviewers: sanjoy, reames
Subscribers: beanz, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D25096
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284855 91177308-0d34-0410-b5e6-96231b3b80d8
When we have a loop with a known upper bound on the number of iterations, and
furthermore know that either the number of iterations will be either exactly
that upper bound or zero, then we can fully unroll up to that upper bound
keeping only the first loop test to check for the zero iteration case.
Most of the work here is in plumbing this 'max-or-zero' information from the
part of scalar evolution where it's detected through to loop unrolling. I've
also gone for the safe default of 'false' everywhere but howManyLessThans which
could probably be improved.
Differential Revision: https://reviews.llvm.org/D25682
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284818 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This allows us to mark when uses have been optimized.
This lets us avoid rewalking (IE when people call getClobberingAccess on everything), and also
enables us to later relax the requirement of use optimization during updates with less cost.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25172
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284771 91177308-0d34-0410-b5e6-96231b3b80d8
All of these existed because MSVC 2013 was unable to synthesize default
move ctors. We recently dropped support for it so all that error-prone
boilerplate can go.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284721 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This pass shrink-wraps a condition to some library calls where the call
result is not used. For example:
sqrt(val);
is transformed to
if (val < 0)
sqrt(val);
Even if the result of library call is not being used, the compiler cannot
safely delete the call because the function can set errno on error
conditions.
Note in many functions, the error condition solely depends on the incoming
parameter. In this optimization, we can generate the condition can lead to
the errno to shrink-wrap the call. Since the chances of hitting the error
condition is low, the runtime call is effectively eliminated.
These partially dead calls are usually results of C++ abstraction penalty
exposed by inlining. This optimization hits 108 times in 19 C/C++ programs
in SPEC2006.
Reviewers: hfinkel, mehdi_amini, davidxl
Subscribers: modocache, mgorny, mehdi_amini, xur, llvm-commits, beanz
Differential Revision: https://reviews.llvm.org/D24414
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284542 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Debug info should *not* affect code generation. This patch properly handles debug info to make sure the generated code are the same with or without debug info.
Reviewers: davidxl, mzolotukhin, jmolloy
Subscribers: aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D25286
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284415 91177308-0d34-0410-b5e6-96231b3b80d8
Not all ConstantExprs can be represented by a global variable, for example most
pointer arithmetic other than addition of a constant, so we can't convert these
values from switch statements to lookup tables.
Differential Revision: https://reviews.llvm.org/D25550
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284379 91177308-0d34-0410-b5e6-96231b3b80d8
BasicBlock::size is O(insts), making this loop O(blocks*insts), which
can be really slow on generated code. getPrevNode already checks if
we're at the beginning of the block and returns nullptr if so, just use
that instead. No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284303 91177308-0d34-0410-b5e6-96231b3b80d8
As Danny pointed out, defClobbersUseOrDef should use MemoryLocOrCall to make
sure fences are properly handled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284099 91177308-0d34-0410-b5e6-96231b3b80d8
This CL didn't actually address the test case in PR30499, and clang
still crashes.
Also revert dependent change "Memory-SSA cleanup of clobbers interface, NFC"
Reverts r283965 and r283967.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284093 91177308-0d34-0410-b5e6-96231b3b80d8
Reappy r284044 after revert in r284051. Krzysztof fixed the error in r284049.
The original summary:
This patch tries to fully unroll loops having break statement like this
for (int i = 0; i < 8; i++) {
if (a[i] == value) {
found = true;
break;
}
}
GCC can fully unroll such loops, but currently LLVM cannot because LLVM only
supports loops having exact constant trip counts.
The upper bound of the trip count can be obtained from calling
ScalarEvolution::getMaxBackedgeTakenCount(). Part of the patch is the
refactoring work in SCEV to prevent duplicating code.
The feature of using the upper bound is enabled under the same circumstance
when runtime unrolling is enabled since both are used to unroll loops without
knowing the exact constant trip count.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284053 91177308-0d34-0410-b5e6-96231b3b80d8
This patch tries to fully unroll loops having break statement like this
for (int i = 0; i < 8; i++) {
if (a[i] == value) {
found = true;
break;
}
}
GCC can fully unroll such loops, but currently LLVM cannot because LLVM only
supports loops having exact constant trip counts.
The upper bound of the trip count can be obtained from calling
ScalarEvolution::getMaxBackedgeTakenCount(). Part of the patch is the
refactoring work in SCEV to prevent duplicating code.
The feature of using the upper bound is enabled under the same circumstance
when runtime unrolling is enabled since both are used to unroll loops without
knowing the exact constant trip count.
Differential Revision: https://reviews.llvm.org/D24790
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284044 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Constant bundle operands may need to retain their constant-ness for
correctness. I'll admit that this is slightly odd, but it looks like
SimplifyCFG already does this for things like @llvm.frameaddress and
@llvm.stackmap, so I suppose adding one more case is not a big deal.
It is possible to add a mechanism to denote bundle operands that need to
remain constants, but that's probably too complicated for the time
being.
Reviewers: jmolloy
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D25502
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284028 91177308-0d34-0410-b5e6-96231b3b80d8
This is a refreshed version of a patch that was reverted: it fixes
the problems reported in both PR30216 and PR30499, and
contains all the test-cases from both bugs.
To hoist stores past loads, we used to search for potential
conflicting loads on the hoisting path by following a MemorySSA
def-def link from the store to be hoisted to the previous
defining memory access, and from there we followed the def-use
chains to all the uses that occur on the hoisting path. The
problem is that the def-def link may point to a store that does
not alias with the store to be hoisted, and so the loads that are
walked may not alias with the store to be hoisted, and even as in
the testcase of PR30216, the loads that may alias with the store
to be hoisted are not visited.
The current patch visits all loads on the path from the store to
be hoisted to the hoisting position and uses the alias analysis
to ask whether the store may alias the load. I was not able to
use the MemorySSA functionality to ask for whether load and
store are clobbered: I'm not sure which function to call, so I
used a call to AA->isNoAlias().
Store past store is still working as before using a MemorySSA
query: I added an extra test to pr30216.ll to make sure store
past store does not regress.
Tested on x86_64-linux with check and a test-suite run.
Differential Revision: https://reviews.llvm.org/D25476
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283965 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: -fsample-profile needs discriminator, which will not be added if built with -g0. This patch makes sure the discriminator is added for sample-profile at -g0. A followup patch will be send out to update clang tests.
Reviewers: davidxl, dblaikie, echristo, dnovillo
Subscribers: mehdi_amini, probinson, llvm-commits
Differential Revision: https://reviews.llvm.org/D25132
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283565 91177308-0d34-0410-b5e6-96231b3b80d8
With the ROPI and RWPI relocation models we can't always have pointers
to global data or functions in constant data, so don't try to convert switches
into lookup tables if any value in the lookup table would require a relocation.
We can still safely emit lookup tables of other values, such as simple
constants.
Differential Revision: https://reviews.llvm.org/D24462
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283530 91177308-0d34-0410-b5e6-96231b3b80d8
GetCaseResults assumed that a terminator with one successor was an
unconditional branch. This is not necessarily the case, it could be a
cleanupret.
Strengthen the check by querying whether or not the terminator is
exceptional.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283517 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a new function to DebugInfo.cpp that takes an llvm::Module
as input and removes all debug info metadata that is not directly
needed for line tables, thus effectively stripping all type and
variable information from the module.
The primary motivation for this feature was the bitcode work flow
(cf. http://lists.llvm.org/pipermail/llvm-dev/2016-June/100643.html
for more background). This is not wired up yet, but will be in
subsequent patches. For testing, the new functionality is exposed to
opt with a -strip-nonlinetable-debuginfo option.
The secondary use-case (and one that works right now!) is as a
reduction pass in bugpoint. I added two new bugpoint options
(-disable-strip-debuginfo and -disable-strip-debug-types) to control
the new features. By default it will first attempt to remove all debug
information, then only the type info, and then proceed to hack at any
remaining MDNodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283473 91177308-0d34-0410-b5e6-96231b3b80d8
LLVM developers might be surprised to learn that there are blocks
without valid insertion points (catchswitch), so it seems worth calling
that out explicitly. Also add a FIXME about what we should really be
doing if we ever need to make optimized Windows EH code debuggable.
While I'm here, make auto usage more consistent with LLVM standards and
avoid an unecessary call to insertBefore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282521 91177308-0d34-0410-b5e6-96231b3b80d8
Return early from llvm::isSafeToDestroyConstant() whenever the value
`isa<ConstantData>()`. These constants are shared across the
LLVMContext. We never really want to delete them here, and walking
their use-lists can be very expensive.
(This is motivated by an eventual goal of removing use-lists entirely
from ConstantData.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282320 91177308-0d34-0410-b5e6-96231b3b80d8
The additional fix is:
When adding debug information to a lowered phi node in mem2reg
check that we have a valid insertion point after the phi for adding
the debug information.
This change addresses the issue in pr30468 where a lowered phi was
added before a catchswitch and no debug information should be added
after the phi in this case.
Differential Revision: https://reviews.llvm.org/D24797
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282155 91177308-0d34-0410-b5e6-96231b3b80d8
The routines llvm::ConvertDebugDeclareToDebugValue() always returned
a true value which was never checked at the call site; change the
function return type to void.
This NFC cleanup was approved in the review https://reviews.llvm.org/D23715
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281964 91177308-0d34-0410-b5e6-96231b3b80d8
When looking at the scribus_1.3 example from https://llvm.org/bugs/show_bug.cgi?id=10584, I noticed that we were spending a large amount of time computing loop exits in LCSSA. This code appears to be written with the assumption that LoopExits are stored in the Loop and thus cheap to query. This is not true, so we should cache the result across the potentially long running loop which tends to visit a small handful of Loops.
On the particular example from 10584, this change drops the time spent in LCSSA computation by about 80%.
Differential Revision: https://reviews.llvm.org/D24509
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281949 91177308-0d34-0410-b5e6-96231b3b80d8
