Commit Graph

636 Commits

Author SHA1 Message Date
Yaxun Liu ea6b796e0e [OpenCL] Fix bug in __builtin_astype causing invalid LLVM cast instructions
__builtin_astype is used to cast OpenCL opaque types to other types, as such, it needs to be able to handle casting from and to pointer types correctly.

Current it cannot handle 1) casting between pointers of different addr spaces 2) casting between pointer type and non-pointer types.

This patch fixes that.

Differential Revision: https://reviews.llvm.org/D25123

llvm-svn: 283114
2016-10-03 14:41:50 +00:00
Yaxun Liu 26f7566ff8 Re-commit [OpenCL] AMDGCN: Fix size_t type
There was a premature cast to pointer type in emitPointerArithmetic which caused assertion in tests with assertion enabled.

llvm-svn: 279206
2016-08-19 05:17:25 +00:00
Yaxun Liu dea5ccb04b Revert [OpenCL] AMDGCN: Fix size_t type
due to regressions in test/CodeGen/exprs.c on certain platforms.

llvm-svn: 279127
2016-08-18 20:01:06 +00:00
Yaxun Liu 6305f8a351 [OpenCL] AMDGCN: Fix size_t type
Pointers of certain GPUs in AMDGCN target in private address space is 32 bit but pointers in other address spaces are 64 bit. size_t type should be defined as 64 bit for these GPUs so that it could hold pointers in all address spaces. Also fixed issues in pointer arithmetic codegen by using pointer specific intptr type.

Differential Revision: https://reviews.llvm.org/D23361

llvm-svn: 279121
2016-08-18 19:34:04 +00:00
Duncan P. N. Exon Smith 01f574cdd5 CodeGen: Avoid dereferencing end() in ScalarExprEmitter::EmitOverflowCheckedBinOp
Use BB.getNextNode(), which returns nullptr on end(), instead of
&*BB.getIterator(), which is UB on end().
CodeGenFunction::createBasicBlock expects nullptr in this case already.

llvm-svn: 278898
2016-08-17 03:15:29 +00:00
James Molloy 5980232178 Left shifts of negative values are defined if -fwrapv is set
This means we shouldn't emit ubsan detection code or warn.
Fixes PR25552.

llvm-svn: 278786
2016-08-16 09:45:36 +00:00
Yaxun Liu ffb60901fe [OpenCL] Handle -cl-fp32-correctly-rounded-divide-sqrt
Let the driver pass the option to frontend. Do not set precision metadata for division instructions when this option is set. Set function attribute "correctly-rounded-divide-sqrt-fp-math" based on this option.

Differential Revision: https://reviews.llvm.org/D22940

llvm-svn: 278155
2016-08-09 20:10:18 +00:00
Yaxun Liu 0bc4b2d337 [OpenCL] Generate opaque type for sampler_t and function call for the initializer
Currently Clang use int32 to represent sampler_t, which have been a source of issue for some backends, because in some backends sampler_t cannot be represented by int32. They have to depend on kernel argument metadata and use IPA to find the sampler arguments and global variables and transform them to target specific sampler type.

This patch uses opaque pointer type opencl.sampler_t* for sampler_t. For each use of file-scope sampler variable, it generates a function call of __translate_sampler_initializer. For each initialization of function-scope sampler variable, it generates a function call of __translate_sampler_initializer.

Each builtin library can implement its own __translate_sampler_initializer(). Since the real sampler type tends to be architecture dependent, allowing it to be initialized by a library function simplifies backend design. A typical implementation of __translate_sampler_initializer could be a table lookup of real sampler literal values. Since its argument is always a literal, the returned pointer is known at compile time and easily optimized to finally become some literal values directly put into image read instructions.

This patch is partially based on Alexey Sotkin's work in Khronos Clang (3d4eec6162).

Differential Revision: https://reviews.llvm.org/D21567

llvm-svn: 277024
2016-07-28 19:26:30 +00:00
Craig Topper f2f1a099a7 [CodeGen] Use llvm::Type::getVectorNumElements instead of casting to llvm::VectorType and calling getNumElements. This is equivalent and shorter.
llvm-svn: 274823
2016-07-08 02:17:35 +00:00
Yaxun Liu c564701fbd [OpenCL] Fix __builtin_astype for vec3 types.
__builtin_astype does not generate correct LLVM IR for vec3 types. This patch inserts bitcasts to/from vec4 when necessary in addition to generating vector shuffle. Sema and codegen tests are added.

Differential Revision: http://reviews.llvm.org/D20133

llvm-svn: 272153
2016-06-08 15:11:21 +00:00
Craig Topper b3174a84b3 [Sema,CodeGen] Remove comment from SemaChecking about a builtin_shufflevector form that it doesn't support. Remove CodeGen support for the same form since it could never have been used due to the missing support in Sema.
I couldn't find any documentation that this form existed either. Nor is there documentation for one of the remaining two forms, but there is a testcase that uses it.

llvm-svn: 269879
2016-05-18 04:11:25 +00:00
Nemanja Ivanovic bb1ea2d613 Enable support for __float128 in Clang and enable it on pertinent platforms
This patch corresponds to reviews:
http://reviews.llvm.org/D15120
http://reviews.llvm.org/D19125

It adds support for the __float128 keyword, literals and target feature to
enable it. Based on the latter of the two aforementioned reviews, this feature
is enabled on Linux on i386/X86 as well as SystemZ.
This is also the second attempt in commiting this feature. The first attempt
did not enable it on required platforms which caused failures when compiling
type_traits with -std=gnu++11.

If you see failures with compiling this header on your platform after this
commit, it is likely that your platform needs to have this feature enabled.

llvm-svn: 268898
2016-05-09 08:52:33 +00:00
Nemanja Ivanovic d7d45bf8ce Revert 266186 as it breaks anything that includes type_traits on some platforms
Since this patch provided support for the __float128 type but disabled it
on all platforms by default, some platforms can't compile type_traits with
-std=gnu++11 since there is a specialization with __float128.
This reverts the patch until D19125 is approved (i.e. we know which platforms
need this support enabled).

llvm-svn: 266460
2016-04-15 18:04:13 +00:00
Nemanja Ivanovic 50f29e06a1 Enable support for __float128 in Clang
This patch corresponds to review:
http://reviews.llvm.org/D15120

It adds support for the __float128 keyword, literals and a target feature to
enable it. This support is disabled by default on all targets and any target
that has support for this type is free to add it.

Based on feedback that I've received from target maintainers, this appears to
be the right thing for most targets. I have not heard from the maintainers of
X86 which I believe supports this type. I will subsequently investigate the
impact of enabling this on X86.

llvm-svn: 266186
2016-04-13 09:49:45 +00:00
Yaxun Liu b7b6d0fc66 [OpenCL] Handle AddressSpaceConversion when target address space does not change.
In codegen different address spaces may be mapped to the same address
space for a target, e.g. in x86/x86-64 all address spaces are mapped
to 0. Therefore AddressSpaceConversion should be translated by
CreatePointerBitCastOrAddrSpaceCast instead of CreateAddrSpaceCast.

Differential Revision: http://reviews.llvm.org/D18713

llvm-svn: 266107
2016-04-12 19:03:49 +00:00
Saleem Abdulrasool 10a4972a8d revert SVN r265702, r265640
Revert the two changes to thread CodeGenOptions into the TargetInfo allocation
and to fix the layering violation by moving CodeGenOptions into Basic.
Code Generation is arguably not particularly "basic".  This addresses Richard's
post-commit review comments.  This change purely does the mechanical revert and
will be followed up with an alternate approach to thread the desired information
into TargetInfo.

llvm-svn: 265806
2016-04-08 16:52:00 +00:00
Saleem Abdulrasool 94cfc603d1 Basic: move CodeGenOptions from Frontend
This is a mechanical move of CodeGenOptions from libFrontend to libBasic.  This
fixes the layering violation introduced earlier by threading CodeGenOptions into
TargetInfo.  It should also fix the modules based self-hosting builds.  NFC.

llvm-svn: 265702
2016-04-07 17:49:44 +00:00
JF Bastien 92f4ef1017 NFC: make AtomicOrdering an enum class
Summary: See LLVM change D18775 for details, this change depends on it.

Reviewers: jyknight, reames

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D18776

llvm-svn: 265569
2016-04-06 17:26:42 +00:00
James Y Knight 29b5f086ca Default vaarg lowering should support indirect struct types.
Fixes PR11517 for SPARC.

On most targets, clang lowers va_arg itself, eschewing the use of the
llvm vaarg instruction. This is necessary (at least for now) as the type
argument to the vaarg instruction cannot represent all the ABI
information that is needed to support complex calling conventions.

However, on targets with a simpler varrags ABIs, the LLVM instruction
can work just fine, and clang can simply lower to it. Unfortunately,
even on such targets, vaarg with a struct argument would fail, because
the default lowering to vaarg was naive: it didn't take into account the
ABI attribute computed by classifyArgumentType. In particular, for the
DefaultABIInfo, structs are supposed to be passed indirectly and so
llvm's vaarg instruction should be emitted with a pointer argument.

Now, vaarg instruction emission is able to use computed ABIArgInfo for
the provided argument type, which allows the default ABI support to work
for structs too.

I haven't touched the EmitVAArg implementation for PPC32_SVR4 or XCore,
although I believe both are now redundant, and could be switched over to
use the default implementation as well.

Differential Revision: http://reviews.llvm.org/D16154

llvm-svn: 261717
2016-02-24 02:59:33 +00:00
John McCall e399e5bd3d Emit calls to objc_unsafeClaimAutoreleasedReturnValue when
reclaiming a call result in order to ignore it or assign it
to an __unsafe_unretained variable.  This avoids adding
an unwanted retain/release pair when the return value is
not actually returned autoreleased (e.g. when it is returned
from a nonatomic getter or a typical collection accessor).

This runtime function is only available on the latest Apple
OS releases; the backwards-compatibility story is that you
don't get the optimization unless your deployment target is
recent enough.  Sorry.

rdar://20530049

llvm-svn: 258962
2016-01-27 18:32:30 +00:00
George Burgess IV df1ed0099b [Bugfix] Fix ICE on constexpr vector splat.
In {CG,}ExprConstant.cpp, we weren't treating vector splats properly.
This patch makes us treat splats more properly.

Additionally, this patch adds a new cast kind which allows a bool->int
cast to result in -1 or 0, instead of 1 or 0 (for true and false,
respectively), so we can sanely model OpenCL bool->int casts in the AST.

Differential Revision: http://reviews.llvm.org/D14877

llvm-svn: 257559
2016-01-13 01:52:39 +00:00
James Y Knight 7281c357b1 [TrailingObjects] Convert OffsetOfExpr.
That necessitated moving the OffsetOfNode class out of OffsetOfExpr.

llvm-svn: 256590
2015-12-29 22:31:18 +00:00
Craig Topper c82f896188 [CodeGen] Use llvm::CmpInst::Predicate instead of unsigned for parameter types in EmitCompare to eliminate some later explicit casts. NFC.
llvm-svn: 255753
2015-12-16 06:24:28 +00:00
Sanjay Patel a30cee6272 change an assert when generating fmuladd to an ordinary 'if' check (PR25719)
We don't want to generate fmuladd if there's a use of the fmul expression, but this shouldn't be an assert.

The test case is derived from the commit message for r253337:
http://reviews.llvm.org/rL253337

That commit reverted r253269:
http://reviews.llvm.org/rL253269

...but the bug exists independently of the default fp-contract setting. It just became easier to hit with that change.

PR25719:
https://llvm.org/bugs/show_bug.cgi?id=25719

Differential Revision: http://reviews.llvm.org/D15165

llvm-svn: 254573
2015-12-03 01:25:12 +00:00
Duncan P. N. Exon Smith 9f5260ab13 CodeGen: Remove implicit ilist iterator conversions, NFC
Make ilist iterator conversions explicit in clangCodeGen.  Eventually
I'll remove them everywhere.

llvm-svn: 252358
2015-11-06 23:00:41 +00:00
Stephen Canon 74f9c1a7aa Allow compound assignment expressions to be contracted when licensed by the language or pragma.
llvm-svn: 252050
2015-11-04 15:25:38 +00:00
Alexey Bataev 2bf9b4c0d1 [DEBUG INFO] Emit debug info for type used in explicit cast only.
Currently debug info for types used in explicit cast only is not emitted. It happened after a patch for better alignment handling. This patch fixes this bug.
Differential Revision: http://reviews.llvm.org/D13582

llvm-svn: 250795
2015-10-20 04:24:12 +00:00
Alexey Bataev f2440332ca Fix crash in codegen on casting to `bool &`.
Currently codegen crashes trying to emit casting to bool &. It happens because bool type is converted to i1 and later then lvalue for reference is converted to i1*. But when codegen tries to load this lvalue it crashes trying to load value from this i1*.

Differential Revision: http://reviews.llvm.org/D13325

llvm-svn: 249534
2015-10-07 10:22:08 +00:00
Anastasia Stulova b02e7835c5 [OpenCL] Fix casting a true boolean to an integer vector.
OpenCL v1.1 s6.2.2: for the boolean value true, every bit in the result vector should be set.

This change treats the i1 value as signed for the purposes of performing the cast to integer,
and therefore sign extend into the result.

Patch by Neil Hickey!

http://reviews.llvm.org/D13349

llvm-svn: 249301
2015-10-05 11:27:41 +00:00
Charles Davis c7d5c94f78 Support __builtin_ms_va_list.
Summary:
This change adds support for `__builtin_ms_va_list`, a GCC extension for
variadic `ms_abi` functions. The existing `__builtin_va_list` support is
inadequate for this because `va_list` is defined differently in the Win64
ABI vs. the System V/AMD64 ABI.

Depends on D1622.

Reviewers: rsmith, rnk, rjmccall

CC: cfe-commits

Differential Revision: http://reviews.llvm.org/D1623

llvm-svn: 247941
2015-09-17 20:55:33 +00:00
John McCall 7f416cc426 Compute and preserve alignment more faithfully in IR-generation.
Introduce an Address type to bundle a pointer value with an
alignment.  Introduce APIs on CGBuilderTy to work with Address
values.  Change core APIs on CGF/CGM to traffic in Address where
appropriate.  Require alignments to be non-zero.  Update a ton
of code to compute and propagate alignment information.

As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment
helper function to CGF and made use of it in a number of places in
the expression emitter.

The end result is that we should now be significantly more correct
when performing operations on objects that are locally known to
be under-aligned.  Since alignment is not reliably tracked in the
type system, there are inherent limits to this, but at least we
are no longer confused by standard operations like derived-to-base
conversions and array-to-pointer decay.  I've also fixed a large
number of bugs where we were applying the complete-object alignment
to a pointer instead of the non-virtual alignment, although most of
these were hidden by the very conservative approach we took with
member alignment.

Also, because IRGen now reliably asserts on zero alignments, we
should no longer be subject to an absurd but frustrating recurring
bug where an incomplete type would report a zero alignment and then
we'd naively do a alignmentAtOffset on it and emit code using an
alignment equal to the largest power-of-two factor of the offset.

We should also now be emitting much more aggressive alignment
attributes in the presence of over-alignment.  In particular,
field access now uses alignmentAtOffset instead of min.

Several times in this patch, I had to change the existing
code-generation pattern in order to more effectively use
the Address APIs.  For the most part, this seems to be a strict
improvement, like doing pointer arithmetic with GEPs instead of
ptrtoint.  That said, I've tried very hard to not change semantics,
but it is likely that I've failed in a few places, for which I
apologize.

ABIArgInfo now always carries the assumed alignment of indirect and
indirect byval arguments.  In order to cut down on what was already
a dauntingly large patch, I changed the code to never set align
attributes in the IR on non-byval indirect arguments.  That is,
we still generate code which assumes that indirect arguments have
the given alignment, but we don't express this information to the
backend except where it's semantically required (i.e. on byvals).
This is likely a minor regression for those targets that did provide
this information, but it'll be trivial to add it back in a later
patch.

I partially punted on applying this work to CGBuiltin.  Please
do not add more uses of the CreateDefaultAligned{Load,Store}
APIs; they will be going away eventually.

llvm-svn: 246985
2015-09-08 08:05:57 +00:00
Filipe Cabecinhas 7af183d841 Propagate SourceLocations through to get a Loc on float_cast_overflow
Summary:
float_cast_overflow is the only UBSan check without a source location attached.
This patch propagates SourceLocations where necessary to get them to the
EmitCheck() call.

Reviewers: rsmith, ABataev, rjmccall

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D11757

llvm-svn: 244568
2015-08-11 04:19:28 +00:00
Filipe Cabecinhas 650d7f7dd5 Don't repeat function names in comments. NFC.
llvm-svn: 244018
2015-08-05 06:19:26 +00:00
Simon Pilgrim 4034b9f0b9 Fix invalid shufflevector operands
This patch fixes bug 23800 ( https://llvm.org/bugs/show_bug.cgi?id=23800#c2 ). There existed a case where the index operand from extractelement was directly used to create a shufflevector mask. Since the index can be of any integral type but the mask must only contain 32 bit integers a 64 bit index operand led to an assertion error later on.

Committed on behalf of mpflanzer (Moritz Pflanzer)

Differential Revision: http://reviews.llvm.org/D10838

llvm-svn: 243851
2015-08-02 15:28:10 +00:00
Benjamin Kramer 9938310ab3 [CodeGen] Simplify creation of shuffle masks.
No functional change intended.

llvm-svn: 243439
2015-07-28 16:25:32 +00:00
Alexey Bataev 0039651304 [OPENMP] Introduced type trait "__builtin_omp_required_simd_align" for default simd alignment.
Adds type trait "__builtin_omp_required_simd_align" after discussions here http://reviews.llvm.org/D9894
Differential Revision: http://reviews.llvm.org/D10597

llvm-svn: 241237
2015-07-02 03:40:19 +00:00
Peter Collingbourne 6708c4a176 Implement diagnostic mode for -fsanitize=cfi*, -fsanitize=cfi-diag.
This causes programs compiled with this flag to print a diagnostic when
a control flow integrity check fails instead of aborting. Diagnostics are
printed using UBSan's runtime library.

The main motivation of this feature over -fsanitize=vptr is fidelity with
the -fsanitize=cfi implementation: the diagnostics are printed under exactly
the same conditions as those which would cause -fsanitize=cfi to abort the
program. This means that the same restrictions apply regarding compiling
all translation units with -fsanitize=cfi, cross-DSO virtual calls are
forbidden, etc.

Differential Revision: http://reviews.llvm.org/D10268

llvm-svn: 240109
2015-06-19 01:51:54 +00:00
David Blaikie 43f9bb7371 API update for streamlining of IRBuilder::CreateCall to just use ArrayRef/initializer_list+braced init
llvm-svn: 237625
2015-05-18 22:14:03 +00:00
Peter Collingbourne 3eea677f3a Unify sanitizer kind representation between the driver and the rest of the compiler.
No functional change.

Differential Revision: http://reviews.llvm.org/D9618

llvm-svn: 237055
2015-05-11 21:39:14 +00:00
Justin Bogner 66242d6c5e InstrProf: Stop using RegionCounter outside of CodeGenPGO (NFC)
The RegionCounter type does a lot of legwork, but most of it is only
meaningful within the implementation of CodeGenPGO. The uses elsewhere
in CodeGen generally just want to increment or read counters, so do
that directly.

llvm-svn: 235664
2015-04-23 23:06:47 +00:00
Alexey Samsonov f624650354 Unify the way we report overflow in increment/decrement operator.
Summary:
Make sure signed overflow in "x--" is checked with
llvm.ssub.with.overflow intrinsic and is reported as:
  "-2147483648 - 1 cannot be represented in type 'int'"
instead of:
  "-2147483648 + -1 cannot be represented in type 'int'"
, like we do for unsigned overflow.

Test Plan: clang + compiler-rt regression test suite

Reviewers: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D8236

llvm-svn: 235568
2015-04-23 01:50:45 +00:00
David Blaikie 1ed728c499 [opaque pointer type] More GEP API migrations
Looks like the VTable code in particular will need some work to pass
around the pointee type explicitly.

llvm-svn: 234128
2015-04-05 22:45:47 +00:00
Alexey Bataev b4505a7229 [OPENMP] Codegen for 'atomic update' construct.
Adds atomic update codegen for the following forms of expressions:

x binop= expr;
x++;
++x;
x--;
--x;
x = x binop expr;
x = expr binop x;
If x and expr are integer and binop is associative or x is a LHS in a RHS of the assignment expression, and atomics are allowed for type of x on the target platform atomicrmw instruction is emitted.
Otherwise compare-and-swap sequence is emitted:

bb:
...
atomic load <x>
cont:
<expected> = phi [ <x>, label %bb ], [ <new_failed>, %cont ]
<desired> = <expected> binop <expr>
<res> = cmpxchg atomic &<x>, desired, expected
<new_failed> = <res>.field1;
br <res>field2, label %exit, label %cont
exit:
...

Differential Revision: http://reviews.llvm.org/D8536

llvm-svn: 233513
2015-03-30 05:20:59 +00:00
Ahmed Bougacha 6ba3831ebe [CodeGen] Support native half inc/dec amounts.
We previously defaulted to long double, but it's also possible to have
a half inc/dec amount, when LangOpts NativeHalfType is set.
Currently, that's only true for OpenCL.

llvm-svn: 233135
2015-03-24 23:44:42 +00:00
Ahmed Bougacha d1801afeac [CodeGen] Properly support the half FP type with non-native operations.
On AArch64, the -fallow-half-args-and-returns option is the default.
With it, the half type is considered legal (rather than the i16 used
normally for __fp16), but no operation is, except conversions and
load/stores and such.

The previous behavior was tantamount to saying LangOpts.NativeHalfType
was implied by LangOpts.HalfArgsAndReturns, which isn't true.
Instead, teach the various parts of CodeGen that already know about
half (using the intrinsics or not) about this weird in-between case,
where the "half" type is legal, but operations on it aren't.

This is a smaller intermediate step to the end-goal of removing the
intrinsic, always using "half", and letting the backend legalize.

Builds on r232968.
rdar://20045970, rdar://17468714
Differential Revision: http://reviews.llvm.org/D8367

llvm-svn: 232971
2015-03-23 17:54:16 +00:00
Ahmed Bougacha 47ec2c7479 [CodeGen] Convert double -> __fp16 in one step.
Fix the CodeGen so that for types bigger than float, instead of
converting to fp16 via the sequence "InTy -> float -> fp16", we
perform conversions in just one step.  This avoids the double
rounding which potentially changes results from a natural
IEEE-754 operation.

rdar://17594379, rdar://17468714
Differential Revision: http://reviews.llvm.org/D4602
Part of: http://reviews.llvm.org/D8367

llvm-svn: 232968
2015-03-23 17:48:07 +00:00
Peter Collingbourne d2926c91d5 Implement bad cast checks using control flow integrity information.
This scheme checks that pointer and lvalue casts are made to an object of
the correct dynamic type; that is, the dynamic type of the object must be
a derived class of the pointee type of the cast. The checks are currently
only introduced where the class being casted to is a polymorphic class.

Differential Revision: http://reviews.llvm.org/D8312

llvm-svn: 232241
2015-03-14 02:42:25 +00:00
Alexey Samsonov 21d2dda3d2 [UBSan] Split -fsanitize=shift into -fsanitize=shift-base and -fsanitize=shift-exponent.
This is a recommit of r231150, reverted in r231409. Turns out
that -fsanitize=shift-base check implementation only works if the
shift exponent is valid, otherwise it contains undefined behavior
itself.

Make sure we check that exponent is valid before we proceed to
check the base. Make sure that we actually report invalid values
of base or exponent if -fsanitize=shift-base or
-fsanitize=shift-exponent is specified, respectively.

llvm-svn: 231711
2015-03-09 21:50:19 +00:00
Alexey Samsonov 48a9db034a Revert "[UBSan] Split -fsanitize=shift into -fsanitize=shift-base and -fsanitize=shift-exponent."
It's not that easy. If we're only checking -fsanitize=shift-base we
still need to verify that exponent has sane value, otherwise
UBSan-inserted checks for base will contain undefined behavior
themselves.

llvm-svn: 231409
2015-03-05 21:57:35 +00:00
Alexey Samsonov 783b8174ad [UBSan] Split -fsanitize=shift into -fsanitize=shift-base and -fsanitize=shift-exponent.
-fsanitize=shift is now a group that includes both these checks, so
exisiting users should not be affected.

This change introduces two new UBSan kinds that sanitize only left-hand
side and right-hand side of shift operation. In practice, invalid
exponent value (negative or too large) tends to cause more portability
problems, including inconsistencies between different compilers, crashes
and inadequeate results on non-x86 architectures etc. That is,
-fsanitize=shift-exponent failures should generally be addressed first.

As a bonus, this change simplifies CodeGen implementation for emitting left
shift (separate checks for base and exponent are now merged by the
existing generic logic in EmitCheck()), and LLVM IR for these checks
(the number of basic blocks is reduced).

llvm-svn: 231150
2015-03-03 22:15:35 +00:00