SCEV currently fails to compute loop counts for nonunit stride
loops. This comes up frequently. It prevents loop optimization and
forces vectorization to insert extra loop checks.
For example:
void foo(int n, int *x) {
for (int i = 0; i < n; i += 3) {
x[i] = i;
x[i+1] = i+1;
x[i+2] = i+2;
}
}
We need to properly handle the case in which limit > INT_MAX-stride. In
the above case: n > INT_MAX-3. In this case the loop counter will step
beyond the limit and overflow at the same time. However, knowing that
signed integer overlow in undefined, we can assume the loop test
behavior is arbitrary after overflow. This obeys both C undefined
behavior rules, and the more strict LLVM poison value rules.
I'm finally fixing this in response to Hal Finkel's persistence.
The most probable reason that we never optimized this before is that
we were being careful to handle case where the developer expected a
side-effect free infinite loop relying on overflow:
for (int i = 0; i < n; i += s) {
++j;
}
return j;
If INT_MAX+1 is a multiple of s and n > INT_MAX-s, then we might
expect an infinite loop. However there are plenty of ways to achieve
this effect without relying on undefined behavior of signed overflow.
llvm-svn: 193015
With this commit, all DIEs created in CompileUnit will be added to parents
inside the same function. Also make getOrCreateTemplateType|Value functions
private.
No functionality change.
llvm-svn: 193002
This is another (final?) stab at making us able to parse our own asm output
on Windows.
Symbols on Windows often contain @'s and ?'s in their names. Our asm parser
didn't like this. ?'s were not allowed, and @'s were intepreted as trying to
reference PLT/GOT/etc.
We can't just add quotes around the bad names, since e.g. for MinGW, we use gas
to assemble, and it doesn't like quotes in some places (notably in .def
directives).
This commit makes us allow ?'s in symbol names, and @'s in symbol names for MS
assembly.
Differential Revision: http://llvm-reviews.chandlerc.com/D1978
llvm-svn: 193000
PR17168 describes a test case that fails when compiling for debug with
fast-isel. Investigation showed that the test was failing because a DBG_VALUE
machine instruction was placed prior to a PHI.
For this problem to occur requires the following:
* Compile for debug
* Compile with fast-isel
* In a block B, fast-isel must partially succeed before punting to DAG-isel
* B must start with a PHI
* The first unhandled node in the DAG must not generate a machine instruction
* A debug value with an order less than that of that first node exists
When all of these circumstances apply, the existing test that an instruction
was not inserted won't fire. Currently it tests whether the block is empty,
or whether the last instruction generated is a phi. When fast-isel has
partially succeeded, the last instruction generated will not be a phi.
Instead, we need to check whether the current insert position is immediately
following a phi. This patch adds that check, and adds the test case from the
PR as a regression test.
llvm-svn: 192976
There are targets that support i128 sized scalars but cannot emit
instructions that modify them directly. The proper thing to do is to
emit a libcall.
This fixes PR17481.
llvm-svn: 192957
gcc diagnoses this:
warning: converting to non-pointer type 'unsigned int' from NULL
Also remove an empty statement.
No change in functionality.
llvm-svn: 192955
This caused the clang-native-mingw32-win7 buildbot to break.
The assembler was complaining about the following lines that were showing up
in the asm for CrashRecoveryContext.cpp:
movl $"__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4", 4(%eax)
calll "_AddVectoredExceptionHandler@8"
.def "__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4";
"__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4":
calll "_RemoveVectoredExceptionHandler@4"
Reverting for now.
llvm-svn: 192940
This commit implements the correct lowering of the
COPY_STRUCT_BYVAL_I32 pseudo-instruction for thumb1 targets.
Previously, the lowering of COPY_STRUCT_BYVAL_I32 generated the
post-increment forms of ldr/ldrh/ldrb instructions. Thumb1 does not
have the post-increment form of these instructions so the generated
assembly contained invalid instructions.
Passing the generated assembly to gcc caused it to complain with an
error like this:
Error: cannot honor width suffix -- `ldrb r3,[r0],#1'
and the integrated assembler would generate an object file with an
invalid instruction encoding.
This commit contains a small test case that demonstrates the problem
with thumb1 targets as well as an expanded test case that more
throughly tests the lowering of byval struct passing for arm,
thumb1, and thumb2 targets.
llvm-svn: 192916
This commit refactors the lowering of the COPY_STRUCT_BYVAL_I32
pseudo-instruction in the ARM backend. We introduce a new helper
class that encapsulates all of the operations needed during the
lowering. The operations are implemented for each subtarget in
different subclasses. Currently only arm and thumb2 subtargets are
supported.
This refactoring was done to easily implement support for thumb1
subtargets. This initial patch does not add support for thumb1, but
is only a refactoring. A follow on patch will implement the support
for thumb1 subtargets.
No intended functionality change.
llvm-svn: 192915
All of the Core API functions have versions which accept explicit context, in
addition to ones which work on global context. This commit adds functions
which accept explicit context to the Target API for consistency.
Patch by Peter Zotov
Differential Revision: http://llvm-reviews.chandlerc.com/D1912
llvm-svn: 192913
class. The instruction class includes the signed saturating doubling
multiply-add long, signed saturating doubling multiply-subtract long, and
the signed saturating doubling multiply long instructions.
llvm-svn: 192908
These were present in a previous version of the MSA spec but are not
present in the published version. There is no hardware that uses these
instructions.
llvm-svn: 192888
When canonicalizing dags according to the rule
(shl (zext (shr X, c1) ), c1) ==> (zext (shl (shr X, c1), c1))
remember to add the new shl dag to the DAGCombiner worklist of nodes.
If we don't explicitly add it to the worklist of nodes to visit, we
may not trigger later on the rule that folds the shift left + logical
shift right into a AND instruction with bitmask.
llvm-svn: 192883
Error handling code for raw_fd_ostream constructor is present, but
never used, because formatted_raw_ostream will always assert on closed
fd's before.
Patch by Peter Zotov
Differential Revision: http://llvm-reviews.chandlerc.com/D1909
llvm-svn: 192881
If no targets are registered, LLVMGetFirstTarget currently fails with
an assertion. This patch makes it return NULL instead, similarly to
how LLVMGetNextTarget would.
Patch by Peter Zotov
Differential Revision: http://llvm-reviews.chandlerc.com/D1908
llvm-svn: 192878
Consider the following:
typedef unsigned short ushort4U __attribute__((ext_vector_type(4),
aligned(2)));
typedef unsigned short ushort4 __attribute__((ext_vector_type(4)));
typedef unsigned short ushort8 __attribute__((ext_vector_type(8)));
typedef int int4 __attribute__((ext_vector_type(4)));
int4 __bbase_cvt_int(ushort4 v) {
ushort8 a;
a.lo = v;
return _mm_cvtepu16_epi32(a);
}
This generates the, not unreasonable, IR:
define <4 x i32> @foo0(double %v.coerce) nounwind ssp {
%tmp = bitcast double %v.coerce to <4 x i16>
%tmp1 = shufflevector <4 x i16> %tmp, <4 x i16> undef, <8 x i32> <i32
%0, i32 1, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
%tmp2 = tail call <4 x i32> @llvm.x86.sse41.pmovzxwd(<8 x i16> %tmp1)
ret <4 x i32> %tmp2
}
The problem is when type legalization gets hold of the v4i16. It
legalizes that by spilling to the stack, then doing a zero-extending
load. Things go even more silly from there, ending up with something
like:
_foo0:
movsd %xmm0, -8(%rsp) <== Spill to the stack.
movq -8(%rsp), %xmm0 <== Reload it right back out.
pmovzxwd %xmm0, %xmm1 <== Here's what we actually asked for.
pblendw $1, %xmm1, %xmm0 <== We don't need this at all
pmovzxwd %xmm0, %xmm0 <== We already did this
ret
The v8i8 to v8i16 zext intrinsic gives even worse results, with two
table lookups via pshufb instructions(!!).
To avoid all that, we can move the bitcasting until after we've formed
the wider (legal) vector type. Then our normal codegen flows along
nicely and we get the expected:
_foo0:
pmovzxwd %xmm0, %xmm0
ret
rdar://15245794
llvm-svn: 192866
like C++ should be the fully qualified names for the type.
Add a routine that does a language specific context walk to build
up the qualified name and use it when we add types/names to the
tables. Expand the gnu pubnames testcase as it's the most complex
to make sure that qualified types are also being added.
llvm-svn: 192865
I expose the API with some caveats:
- The C++ API involves a traditional void* opaque pointer for the fatal
error callback. The C API doesn’t do this. I don’t think that the void*
opaque pointer makes any sense since this is a global callback - there will
only be one of them. So if you need to pass some data to your callback,
just put it in a global variable.
- The bindings will ignore the gen_crash_diag boolean. I ignore it because
(1) I don’t know what it does, (2) it’s not documented AFAIK, and (3) I
couldn’t imagine any use for it. I made the gut call that it probably
wasn’t important enough to expose through the C API.
llvm-svn: 192864
The reason this got reverted was that the @feat.00 symbol which was emitted
for every TU became quoted, and on cygwin/mingw we use the gas assembler which
couldn't handle the quotes.
This commit fixes the problem by only emitting @feat.00 for win32, where we use
clang -cc1as to assemble. gas would just drop this symbol anyway, so there is no
loss there.
With @feat.00 gone, there shouldn't be quoted symbols showing up on cygwin since
it uses the Itanium ABI, which doesn't put these funny characters in symbols.
> Because of win32 mangling, we produce symbol and section names with
> funny characters in them, most notably @ characters.
>
> MC would choke on trying to parse its own assembly output. This patch addresses
> that by:
>
> - Making @ trigger quoting of symbol names
> - Also quote section names in the same way
> - Just parse section names like other identifiers (to allow for quotes)
> - Don't assume @ signifies a symbol variant if it is in a string.
llvm-svn: 192859
Andrew Trick