Commit Graph

104 Commits

Author SHA1 Message Date
Benjamin Kramer bb70d751de [SimplifyLibCalls] Drop default template args. No functional change.
llvm-svn: 245189
2015-08-16 21:16:37 +00:00
Sanjay Patel 57fd1dc5db transform fmin/fmax calls when possible (PR24314)
If we can ignore NaNs, fmin/fmax libcalls can become compare and select
(this is what we turn std::min / std::max into).

This IR should then be optimized in the backend to whatever is best for
any given target. Eg, x86 can use minss/maxss instructions.

This should solve PR24314:
https://llvm.org/bugs/show_bug.cgi?id=24314

Differential Revision: http://reviews.llvm.org/D11866

llvm-svn: 245187
2015-08-16 20:18:19 +00:00
Davide Italiano a195386ca1 [SimplifyLibCalls] Correctly set the is_zero_undef flag for llvm.cttz
If <src> is non-zero we can safely set the flag to true, and this
results in less code generated for, e.g. ffs(x) + 1 on FreeBSD.
Thanks to majnemer for suggesting the fix and reviewing.

Code generated before the patch was applied:


 0:   0f bc c7                bsf    %edi,%eax
 3:   b9 20 00 00 00          mov    $0x20,%ecx
 8:   0f 45 c8                cmovne %eax,%ecx
 b:   83 c1 02                add    $0x2,%ecx
 e:   b8 01 00 00 00          mov    $0x1,%eax
13:   85 ff                   test   %edi,%edi
15:   0f 45 c1                cmovne %ecx,%eax
18:   c3                      retq

Code generated after the patch was applied:

 0:   0f bc cf                bsf    %edi,%ecx
 3:   83 c1 02                add    $0x2,%ecx
 6:   85 ff                   test   %edi,%edi
 8:   b8 01 00 00 00          mov    $0x1,%eax
 d:   0f 45 c1                cmovne %ecx,%eax
10:   c3                      retq

It seems we can still use cmove and save another 'test' instruction, but
that can be tackled separately.

Differential Revision:  http://reviews.llvm.org/D11989	

llvm-svn: 244947
2015-08-13 20:34:26 +00:00
Sanjay Patel e24c60eb54 fix typo; NFC
llvm-svn: 244805
2015-08-12 20:36:18 +00:00
Pete Cooper 9e1d335697 Change Function::getIntrinsicID() to return an Intrinsic::ID. NFC.
Now that Intrinsic::ID is a typed enum, we can forward declare it and so return it from this method.

This updates all users which were either using an unsigned to store it, or had a now unnecessary cast.

llvm-svn: 237810
2015-05-20 17:16:39 +00:00
David Blaikie ff6409d096 Simplify IRBuilder::CreateCall* by using ArrayRef+initializer_list/braced init only
llvm-svn: 237624
2015-05-18 22:13:54 +00:00
David Blaikie aa41cd57e0 [opaque pointer type] More GEP IRBuilder API migrations...
llvm-svn: 234058
2015-04-03 21:33:42 +00:00
David Blaikie 65fab6d896 Use early returns to reduce indentation.
llvm-svn: 234057
2015-04-03 21:32:06 +00:00
Ahmed Bougacha 408d010a7c [SimplifyLibCalls] Ignore nobuiltin/unavailable fortified libcalls.
We used to do this before refactorings around r225640.
Some clang users checked for _chk libcall availability using:
  __has_builtin(__builtin___memcpy_chk)
When compiling with -fno-builtin, this is always true.
When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
end up with fortified libcalls, which isn't acceptable in a freestanding
environment which only provides their non-fortified counterparts.

Until we change clang and/or teach external users to check for availability
differently, disregard the "nobuiltin" attribute and TLI::has.

Workaround for PR23093.

llvm-svn: 233776
2015-04-01 00:45:09 +00:00
David Blaikie 3909da7f4b [opaque pointer type] More IRBuilder::createGEP (non-inbounds) migrations: CodeGenPrepare and SimplifyLibCalls
llvm-svn: 233596
2015-03-30 20:42:56 +00:00
Benjamin Kramer d6aa0ec737 [SimplifyLibCalls] Fix negative shifts being produced by the memchr -> bitfield transform.
llvm-svn: 232903
2015-03-21 22:04:26 +00:00
Benjamin Kramer 7857d723f1 [SimplifyLibCalls] Turn memchr(const, C, const) into a bitfield check.
strchr("123!", C) != nullptr is a common pattern to check if C is one
of 1, 2, 3 or !. If the largest element of the string is smaller than
the target's register size we can easily create a bitfield and just
do a simple test for set membership.

int foo(char C) { return strchr("123!", C) != nullptr; } now becomes

	cmpl	$64, %edi ## range check
	sbbb	%al, %al
	movabsq	$0xE000200000001, %rcx
	btq	%rdi, %rcx ## bit test
	sbbb	%cl, %cl
	andb	%al, %cl ## and the two conditions
	andb	$1, %cl
	movzbl	%cl, %eax ## returning an int
	ret

(imho the backend should expand this into a series of branches, but
that's a different story)

The code is currently limited to bit fields that fit in a register, so
usually 64 or 32 bits. Sadly, this misses anything using alpha chars
or {}. This could be fixed by just emitting a i128 bit field, but that
can generate really ugly code so we have to find a better way. To some
degree this is also recreating switch lowering logic, but we can't
simply emit a switch instruction and thus change the CFG within
instcombine.

llvm-svn: 232902
2015-03-21 21:09:33 +00:00
Benjamin Kramer 691363e7f2 SimplifyLibCalls: Add basic optimization of memchr calls.
This is just memchr(x, y, 0) -> nullptr and constant folding.

llvm-svn: 232896
2015-03-21 15:36:21 +00:00
Mehdi Amini a28d91d81b DataLayout is mandatory, update the API to reflect it with references.
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.

This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.

I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.

I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.

Test Plan:

Reviewers: echristo

Subscribers: llvm-commits

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231740
2015-03-10 02:37:25 +00:00
Ahmed Bougacha 1ac9356524 [SimplifyLibCalls] Don't confuse strcpy_chk for stpcpy_chk.
This was introduced in a faulty refactoring (r225640, mea culpa):
the tests weren't testing the return values, so, for both
__strcpy_chk and __stpcpy_chk, we would return the end of the
buffer (matching stpcpy) instead of the beginning (for strcpy).

The root cause was the prefix "__" being ignored when comparing,
which made us always pick LibFunc::stpcpy_chk.
Pass the LibFunc::Func directly to avoid this kind of error.
Also, make the testcases as explicit as possible to prevent this.

The now-useful testcases expose another, entangled, stpcpy problem,
with the further simplification.  This was introduced in a
refactoring (r225640) to match the original behavior.

However, this leads to problems when successive simplifications
generate several similar instructions, none of which are removed
by the custom replaceAllUsesWith.

For instance, InstCombine (the main user) doesn't erase the
instruction in its custom RAUW.  When trying to simplify say
__stpcpy_chk:
- first, an stpcpy is created (fortified simplifier),
- second, a memcpy is created (normal simplifier), but the
  stpcpy call isn't removed.
- third, InstCombine later revisits the instructions,
  and simplifies the first stpcpy to a memcpy.  We now have
  two memcpys.

llvm-svn: 227250
2015-01-27 21:52:16 +00:00
Chandler Carruth 9280382ac6 [PM] Replace an abuse of inheritance to override a single function with
a more direct approach: a type-erased glorified function pointer. Now we
can pass a function pointer into this for the easy case and we can even
pass a lambda into it in the interesting case in the instruction
combiner.

I'll be using this shortly to simplify the interfaces to InstCombiner,
but this helps pave the way and seems like a better design for the
libcall simplifier utility.

llvm-svn: 226640
2015-01-21 02:11:59 +00:00
Chandler Carruth 62d4215baa [PM] Move TargetLibraryInfo into the Analysis library.
While the term "Target" is in the name, it doesn't really have to do
with the LLVM Target library -- this isn't an abstraction which LLVM
targets generally need to implement or extend. It has much more to do
with modeling the various runtime libraries on different OSes and with
different runtime environments. The "target" in this sense is the more
general sense of a target of cross compilation.

This is in preparation for porting this analysis to the new pass
manager.

No functionality changed, and updates inbound for Clang and Polly.

llvm-svn: 226078
2015-01-15 02:16:27 +00:00
Ahmed Bougacha 71d7b18e3d [SimplifyLibCalls] Don't try to simplify indirect calls.
It turns out, all callsites of the simplifier are guarded by a check for
CallInst::getCalledFunction (i.e., to make sure the callee is direct).

This check wasn't done when trying to further optimize a simplified fortified
libcall, introduced by a refactoring in r225640.

Fix that, add a testcase, and document the requirement.

llvm-svn: 225895
2015-01-14 00:55:05 +00:00
Ahmed Bougacha e03bef7543 [SimplifyLibCalls] Factor out fortified libcall handling.
This lets us remove CGP duplicate.

Differential Revision: http://reviews.llvm.org/D6541

llvm-svn: 225640
2015-01-12 17:22:43 +00:00
Ahmed Bougacha 6722f5e5b3 [SimplifyLibCalls] Factor out str/mem libcall optimizations.
Put them in a separate function, so we can reuse them to further
simplify fortified libcalls as well.

Differential Revision: http://reviews.llvm.org/D6540

llvm-svn: 225639
2015-01-12 17:20:06 +00:00
Ahmed Bougacha b7d8afb6c5 [SimplifyLibCalls] Factor out signature checks for fortifiable libcalls.
The checks are the same for fortified counterparts to the libcalls, so
we might as well do them in a single place.

Differential Revision: http://reviews.llvm.org/D6539

llvm-svn: 225638
2015-01-12 17:18:19 +00:00
Matthias Braun 395a82f6cc correct spelling, NFC
llvm-svn: 223274
2014-12-03 22:10:39 +00:00
Matthias Braun d34e4d2354 [SimplifyLibCalls] Improve double->float shrinking to consider constants
This allows cases like float x; fmin(1.0, x); to be optimized to fminf(1.0f, x);

rdar://19049359

Differential Revision: http://reviews.llvm.org/D6496

llvm-svn: 223270
2014-12-03 21:46:33 +00:00
Matthias Braun 892c923c46 [SimplifyLibCalls] Enable double to float shrinking for copysign
rdar://19049359

Differential Revision: http://reviews.llvm.org/D6495

llvm-svn: 223269
2014-12-03 21:46:29 +00:00
Reid Kleckner 971c3ea67b Use nullptr instead of NULL for variadic sentinels
Windows defines NULL to 0, which when used as an argument to a variadic
function, is not a null pointer constant. As a result, Clang's
-Wsentinel fires on this code. Using '0' would be wrong on most 64-bit
platforms, but both MSVC and Clang make it work on Windows. Sidestep the
issue with nullptr.

llvm-svn: 221940
2014-11-13 22:55:19 +00:00
Ahmed Bougacha 55a333d89b Add fortified (__*_chk) library functions to TLI (NFC)
One of them (__memcpy_chk) was already there, the others were checked
by comparing function names.
Note that the fortified libfuncs are now part of TLI, but are always
available, because they aren't generated, only optimized into the
non-checking versions.

Differential Revision: http://reviews.llvm.org/D6179

llvm-svn: 221817
2014-11-12 21:23:34 +00:00
Sanjay Patel 848309da7c Handle sqrt() shrinking in SimplifyLibCalls like any other call
This patch removes a chunk of special case logic for folding 
(float)sqrt((double)x) -> sqrtf(x)
in InstCombineCasts and handles it in the mainstream path of SimplifyLibCalls.

No functional change intended, but I loosened the restriction on the existing
sqrt testcases to allow for this optimization even without unsafe-fp-math because
that's the existing behavior.

I also added a missing test case for not shrinking the llvm.sqrt.f64 intrinsic
in case the result is used as a double.

Differential Revision: http://reviews.llvm.org/D5919

llvm-svn: 220514
2014-10-23 21:52:45 +00:00
Sanjay Patel a92fa44740 Shrinkify libcalls: use float versions of double libm functions with fast-math (bug 17850)
When a call to a double-precision libm function has fast-math semantics 
(via function attribute for now because there is no IR-level FMF on calls), 
we can avoid fpext/fptrunc operations and use the float version of the call
if the input and output are both float.

We already do this optimization using a command-line option; this patch just
adds the ability for fast-math to use the existing functionality.

I moved the cl::opt from InstructionCombining into SimplifyLibCalls because
it's only ever used internally to that class.

Modified the existing test cases to use the unsafe-fp-math attribute rather
than repeating all tests.

This patch should solve: http://llvm.org/bugs/show_bug.cgi?id=17850

Differential Revision: http://reviews.llvm.org/D5893

llvm-svn: 220390
2014-10-22 15:29:23 +00:00
Sanjay Patel c699a6117b fold: sqrt(x * x * y) -> fabs(x) * sqrt(y)
If a square root call has an FP multiplication argument that can be reassociated,
then we can hoist a repeated factor out of the square root call and into a fabs().

In the simplest case, this:

   y = sqrt(x * x);

becomes this:

   y = fabs(x);

This patch relies on an earlier optimization in instcombine or reassociate to put the
multiplication tree into a canonical form, so we don't have to search over
every permutation of the multiplication tree.

Because there are no IR-level FastMathFlags for intrinsics (PR21290), we have to
use function-level attributes to do this optimization. This needs to be fixed
for both the intrinsics and in the backend.

Differential Revision: http://reviews.llvm.org/D5787

llvm-svn: 219944
2014-10-16 18:48:17 +00:00
Sanjay Patel 0ca42bb5a8 Optimize away fabs() calls when input is squared (known positive).
Eliminate library calls and intrinsic calls to fabs when the input 
is a squared value.

Note that no unsafe-math / fast-math assumptions are needed for
this optimization.

Differential Revision: http://reviews.llvm.org/D5777

llvm-svn: 219717
2014-10-14 20:43:11 +00:00
Chris Bieneman cf93cbb7a4 Fixing a build error.
llvm-svn: 217983
2014-09-17 21:06:59 +00:00
Chris Bieneman ad070d0588 Refactoring SimplifyLibCalls to remove static initializers and generally cleaning up the code.
Summary: This eliminates ~200 lines of code mostly file scoped struct definitions that were unnecessary.

Reviewers: chandlerc, resistor

Reviewed By: resistor

Subscribers: morisset, resistor, llvm-commits

Differential Revision: http://reviews.llvm.org/D5364

llvm-svn: 217982
2014-09-17 20:55:46 +00:00
Diego Novillo 7f8af8bf91 Add support for missed and analysis optimization remarks.
Summary:
This adds two new diagnostics: -pass-remarks-missed and
-pass-remarks-analysis. They take the same values as -pass-remarks but
are intended to be triggered in different contexts.

-pass-remarks-missed is used by LLVMContext::emitOptimizationRemarkMissed,
which passes call when they tried to apply a transformation but
couldn't.

-pass-remarks-analysis is used by LLVMContext::emitOptimizationRemarkAnalysis,
which passes call when they want to inform the user about analysis
results.

The patch also:

1- Adds support in the inliner for the two new remarks and a
   test case.

2- Moves emitOptimizationRemark* functions to the llvm namespace.

3- Adds an LLVMContext argument instead of making them member functions
   of LLVMContext.

Reviewers: qcolombet

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D3682

llvm-svn: 209442
2014-05-22 14:19:46 +00:00
Nick Lewycky 718ada97bc Fold strlen(expr ? "str1" : "str2") to x ? len1 : len2. This fires about 330 times in a bootstrap of clang.
llvm-svn: 207828
2014-05-02 04:11:45 +00:00
Craig Topper f40110f4d8 [C++] Use 'nullptr'. Transforms edition.
llvm-svn: 207196
2014-04-25 05:29:35 +00:00
Chandler Carruth cdf4788401 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

llvm-svn: 203364
2014-03-09 03:16:01 +00:00
Craig Topper 3e4c697ca1 [C++11] Add 'override' keyword to virtual methods that override their base class.
llvm-svn: 202953
2014-03-05 09:10:37 +00:00
Rafael Espindola 37dc9e19f5 Rename many DataLayout variables from TD to DL.
I am really sorry for the noise, but the current state where some parts of the
code use TD (from the old name: TargetData) and other parts use DL makes it
hard to write a patch that changes where those variables come from and how
they are passed along.

llvm-svn: 201827
2014-02-21 00:06:31 +00:00
Benjamin Kramer 34f460ed29 SimplifyLibCalls: Push TLI through the exp2->ldexp transform.
For the odd case of platforms with exp2 available but not ldexp.

llvm-svn: 200795
2014-02-04 20:27:23 +00:00
Tim Northover 103e648d30 OS X: the correct function is __sincospif_stret, not __sincospi_stretf
rdar://problem/13729466

llvm-svn: 200771
2014-02-04 16:28:20 +00:00
Kai Nacke a56bb78021 Add strchr(p, 0) -> p + strlen(p) to SimplifyLibCalls
Add the missing transformation strchr(p, 0) -> p + strlen(p) to SimplifyLibCalls
and remove the ToDo comment.

Reviewer: Duncan P.N. Exan Smith
llvm-svn: 200736
2014-02-04 05:55:16 +00:00
Yi Jiang 6ab044ee35 Enable double to float shrinking optimizations for binary functions like 'fmin/fmax'. Fix radar:15283121
llvm-svn: 197434
2013-12-16 22:42:40 +00:00
Yi Jiang f92a574246 Resubmit r196544: Apply transformation on OS X 10.9+ and iOS 7.0+: pow(10, x) ―> __exp10(x)
llvm-svn: 197109
2013-12-12 01:55:04 +00:00
Manman Ren 2e06c8c777 Revert 196544 due to internal bot failures.
llvm-svn: 196732
2013-12-08 20:28:33 +00:00
Yi Jiang 01cfa94212 Apply transformation on OS X 10.9+ and iOS 7.0+: pow(10, x) ―> __exp10(x)
llvm-svn: 196544
2013-12-05 22:42:50 +00:00
Hal Finkel 66cd3f1ba3 Add the cold attribute to error-reporting call sites
Generally speaking, control flow paths with error reporting calls are cold.
So far, error reporting calls are calls to perror and calls to fprintf,
fwrite, etc. with stderr as the stream. This can be extended in the future.

The primary motivation is to improve block placement (the cold attribute
affects the static branch prediction heuristics).

llvm-svn: 194943
2013-11-17 02:06:35 +00:00
Matt Arsenault c900303e2f Use type form of getIntPtrType.
This should be inconsequential and is work
towards removing the default address space
arguments.

llvm-svn: 194347
2013-11-10 04:46:57 +00:00
Bob Wilson d8d92d90fa Convert calls to __sinpi and __cospi into __sincospi_stret
This adds an SimplifyLibCalls case which converts the special __sinpi and
__cospi (float & double variants) into a __sincospi_stret where appropriate to
remove duplicated work.

Patch by Tim Northover

llvm-svn: 193943
2013-11-03 06:48:38 +00:00
Matt Arsenault f631f8c640 Use StringRef::npos for StringRef instead of std::string one
llvm-svn: 190375
2013-09-10 00:41:53 +00:00
Benjamin Kramer 2702caad08 SimplifyLibCalls: When emitting an overloaded fp function check that it's available.
The existing code missed some edge cases when e.g. we're going to emit sqrtf but
only the availability of sqrt was checked. This happens on odd platforms like
windows.

llvm-svn: 189724
2013-08-31 18:19:35 +00:00