Initial support for asm goto w/ outputs (D69876) only supported outputs
along the "default" (aka "fallthrough") edge.
We can support outputs along all edges by repeating the same pattern of
stores along the indirect edges that we allready do for the default
edge. One complication is that these indirect edges may be critical
edges which would need to be split. Another issue is that mid-codgen of
LLVM IR, the control flow graph might not reflect the control flow of
the final function.
To avoid this "chicken and the egg" problem assume that any given
indirect edge may become a critical edge, and pro-actively split it.
This is unnecessary if the edge does not become critical, but LLVM will
optimize such cases via tail duplication.
Fixes: https://github.com/llvm/llvm-project/issues/53562
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D136497
Prerequisite to further modifications in D136497.
Basically, there is a large body of code in CodeGenFunction::EmitAsmStmt
for emitting stores of outputs. We want to be able to repeat this logic,
for each destination of a callbr (rather than just the default
destination which is what the code currently does).
Also does some smaller cleanups like whitespace cleanups, and removing
pointless casts.
Reviewed By: void, jyknight
Differential Revision: https://reviews.llvm.org/D137113
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Generally, with PGO enabled the C++20 likelyhood attributes shall be
dropped assuming the profile has a good coverage. However, currently
this is not the case for the following code:
if (always_false()) [[likely]] {
...
}
The patch fixes this and drops the attribute, if the parent context was
executed in the profile. The patch still preserves the attribute, if the
parent context was not executed, e.g. to support the cases when the
profile has insufficient coverage.
Differential Revision: https://reviews.llvm.org/D134456
Currently, clang does not emit debuginfo for the switch stmt
case value if it is an enum value. For example,
$ cat test.c
enum { AA = 1, BB = 2 };
int func1(int a) {
switch(a) {
case AA: return 10;
case BB: return 11;
default: break;
}
return 0;
}
$ llvm-dwarfdump test.o | grep AA
$
Note that gcc does emit debuginfo for the same test case.
This patch added such a support with similar implementation
to CodeGenFunction::EmitDeclRefExprDbgValue(). With this patch,
$ clang -g -c test.c
$ llvm-dwarfdump test.o | grep AA
DW_AT_name ("AA")
$
Differential Revision: https://reviews.llvm.org/D134705
GCC inline asm document says that
"... the general rule is that the output variable must be a scalar
integer, and the value is boolean."
Commit e5c37958f901cc9bec50624dbee85d40143e4bca lowers flag output of
inline asm on X86 with setcc, hence it is guaranteed that the flag
is of boolean value. Clang does not support ARM inline asm flag output
yet so nothing need to be worried about ARM.
See "Flag Output" section at
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#OutputOperands
Fixes https://github.com/llvm/llvm-project/issues/56568
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D129954
Following some recent discussions, this changes the representation
of callbrs in IR. The current blockaddress arguments are replaced
with `!` label constraints that refer directly to callbr indirect
destinations:
; Before:
%res = callbr i8* asm "", "=r,r,i"(i8* %x, i8* blockaddress(@test8, %foo))
to label %asm.fallthrough [label %foo]
; After:
%res = callbr i8* asm "", "=r,r,!i"(i8* %x)
to label %asm.fallthrough [label %foo]
The benefit of this is that we can easily update the successors of
a callbr, without having to worry about also updating blockaddress
references. This should allow us to remove some limitations:
* Allow unrolling/peeling/rotation of callbr, or any other
clone-based optimizations
(https://github.com/llvm/llvm-project/issues/41834)
* Allow duplicate successors
(https://github.com/llvm/llvm-project/issues/45248)
This is just the IR representation change though, I will follow up
with patches to remove limtations in various transformation passes
that are no longer needed.
Differential Revision: https://reviews.llvm.org/D129288
This patch gives basic parsing and semantic support for
"parallel masked taskloop simd" construct introduced in
OpenMP 5.1 (section 2.16.10)
Differential Revision: https://reviews.llvm.org/D128946
This patch gives basic parsing and semantic support for
"parallel masked taskloop" construct introduced in
OpenMP 5.1 (section 2.16.9)
Differential Revision: https://reviews.llvm.org/D128834
This patch gives basic parsing and semantic support for
"masked taskloop simd" construct introduced in OpenMP 5.1 (section 2.16.8)
Differential Revision: https://reviews.llvm.org/D128693
This patch gives basic parsing and semantic support for "masked taskloop"
construct introduced in OpenMP 5.1 (section 2.16.7)
Differential Revision: https://reviews.llvm.org/D128478
Instead, just pop the cleanups at the end of the asm statement.
This fixes an assertion failure in BuildStmtExpr. It also fixes a bug
where blocks and C compound literals were destructed at the end of the
asm statement instead of at the end of the enclosing scope.
Differential Revision: https://reviews.llvm.org/D125936
Adds basic parsing/sema/serialization support for the
#pragma omp target parallel loop directive.
Differential Revision: https://reviews.llvm.org/D122359
GCC supports power-of-2 size structures for the arguments. Clang supports fewer than GCC. But Clang always crashes for the unsupported cases.
This patch adds sema checks to do the diagnosts to solve these crashes.
Reviewed By: jyu2
Differential Revision: https://reviews.llvm.org/D107141
Motivation:
```
int test(int x, int y) {
int r = 0;
[[clang::always_inline]] r += foo(x, y); // force compiler to inline this function here
return r;
}
```
In 2018, @kuhar proposed "Introduce per-callsite inline intrinsics" in https://reviews.llvm.org/D51200 to solve this motivation case (and many others).
This patch solves this problem with call site attribute. "noinline" statement attribute already landed in D119061. Also, some LLVM Inliner fixes landed so call site attribute is stronger than function attribute.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D120717
Clang is crashing on the following statement
char var[9];
__asm__ ("" : "=r" (var) : "0" (var));
This is similar to existing test: crbug_999160_regtest
The issue happens when EmitAsmStmt is trying to convert input to match
output type length. However, that is not guaranteed to be successful all the
time and if the statement itself is invalid like having an array type in
the example, we should give a regular error message here instead of
using assert().
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D120596
Motivation:
```
int foo(int x, int y) { // any compiler will happily inline this function
return x / y;
}
int test(int x, int y) {
int r = 0;
[[clang::noinline]] r += foo(x, y); // for some reason we don't want any inlining here
return r;
}
```
In 2018, @kuhar proposed "Introduce per-callsite inline intrinsics" in https://reviews.llvm.org/D51200 to solve this motivation case (and many others).
This patch solves this problem with call site attribute. The implementation is "smaller" wrt approach which uses new intrinsics and thanks to https://reviews.llvm.org/D79121 (Add nomerge statement attribute to clang), we have got some basic infrastructure to deal with attrs on statements with call expressions.
GCC devs are more inclined to call attribute solution as well, as builtins are problematic for them - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104187. But they have no patch proposal yet so.. We have free hands here.
If this approach makes sense, next future steps would be support for call site attributes for always_inline / flatten.
Reviewed By: aaron.ballman, kuhar
Differential Revision: https://reviews.llvm.org/D119061
I noticed that the following case would compile in Clang but not GCC:
void *x(void) {
void *p = &&foo;
asm goto ("# %0\n\t# %l1":"+r"(p):::foo);
foo:;
return p;
}
Changing the output template above from %l2 would compile in GCC but not
Clang.
This demonstrates that when using tied outputs (say via the "+r" output
constraint), the hidden inputs occur or are numbered BEFORE the labels,
at least with GCC.
In fact, GCC does denote this in its documentation:
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
> Output operand with constraint modifier ‘+’ is counted as two operands
> because it is considered as one output and one input operand.
For the sake of compatibility, I think it's worthwhile to just make this
change.
It's better to use symbolic names for compatibility (especially now
between released version of Clang that support asm goto with outputs).
ie. %l1 from the above would be %l[foo]. The GCC docs also make this
recommendation.
Also, I cleaned up some cruft in GCCAsmStmt::getNamedOperand. AFAICT,
NumPlusOperands was no longer used, though I couldn't find which commit
didn't clean that up correctly.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103640
Link: https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D115471
This implements the clang side of D116531. The elementtype
attribute is added for all indirect constraints (*) and tests are
updated accordingly.
Differential Revision: https://reviews.llvm.org/D116666
In 32bit mode, attaching TBAA metadata to the store following the call
to inline assembler results in describing the wrong type by making a
fake lvalue(i.e., whatever the inline assembler happens to leave in
EAX:EDX.) Even if inline assembler somehow describes the correct type,
setting TBAA information on return type of call to inline assembler is
likely not correct, since TBAA rules need not apply to inline assembler.
Differential Revision: https://reviews.llvm.org/D115320
With this,
void f() { __asm__("mov eax, ebx"); }
now compiles with clang with -masm=intel.
This matches gcc.
The flag is not accepted in clang-cl mode. It has no effect on
MSVC-style `__asm {}` blocks, which are unconditionally in intel
mode both before and after this change.
One difference to gcc is that in clang, inline asm strings are
"local" while they're "global" in gcc. Building the following with
-masm=intel works with clang, but not with gcc where the ".att_syntax"
from the 2nd __asm__() is in effect until file end (or until a
".intel_syntax" somewhere later in the file):
__asm__("mov eax, ebx");
__asm__(".att_syntax\nmovl %ebx, %eax");
__asm__("mov eax, ebx");
This also updates clang's intrinsic headers to work both in
-masm=att (the default) and -masm=intel modes.
The official solution for this according to "Multiple assembler dialects in asm
templates" in gcc docs->Extensions->Inline Assembly->Extended Asm
is to write every inline asm snippet twice:
bt{l %[Offset],%[Base] | %[Base],%[Offset]}
This works in LLVM after D113932 and D113894, so use that.
(Just putting `.att_syntax` at the start of the snippet works in some but not
all cases: When LLVM interpolates in parameters like `%0`, it uses at&t or
intel syntax according to the inline asm snippet's flavor, so the `.att_syntax`
within the snippet happens to late: The interpolated-in parameter is already
in intel style, and then won't parse in the switched `.att_syntax`.)
It might be nice to invent a `#pragma clang asm_dialect push "att"` /
`#pragma clang asm_dialect pop` to be able to force asm style per snippet,
so that the inline asm string doesn't contain the same code in two variants,
but let's leave that for a follow-up.
Fixes PR21401 and PR20241.
Differential Revision: https://reviews.llvm.org/D113707
This patch removes the assumption propagation that was added in D110655
primarily to get assumption informatino on opaque call sites for
optimizations. The analysis done in D111445 allows us to do this more
intelligently in the back-end.
Depends on D111445
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D111463
Modify the IfStmt node to suppoort constant evaluated expressions.
Add a new ExpressionEvaluationContext::ImmediateFunctionContext to
keep track of immediate function contexts.
This proved easier/better/probably more efficient than walking the AST
backward as it allows diagnosing nested if consteval statements.
This patch adds OpenMP assumption attributes to call sites in applicable
regions. Currently this applies the caller's assumption attributes to
any calls contained within it. So, if a call occurs inside an OpenMP
assumes region to a function outside that region, we will assume that
call respects the assumptions. This is primarily useful for inline
assembly calls used heavily in the OpenMP GPU device runtime, which
allows us to then make judgements about what the ASM will do.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D110655
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
This fixes a bug in clang where, when clang sees a switch with a
fallthrough to a default like this:
static void funcA(void) {}
static void funcB(void) {}
int main(int argc, char **argv) {
switch (argc) {
case 0:
funcA();
break;
case 10:
default:
funcB();
break;
}
}
It does not add a proper debug location for that switch case, such as
case 10: above.
Patch by Shubham Rastogi!
Differential Revision: https://reviews.llvm.org/D109940
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
In LLVM IR terms the ACLE type 'data512_t' is essentially an aggregate
type { [8 x i64] }. When emitting code for inline assembly operands,
clang tries to scalarize aggregate types to an integer of the equivalent
length, otherwise it passes them by-reference. This patch adds a target
hook to tell whether a given inline assembly operand is scalarizable
so that clang can emit code to pass/return it by-value.
Differential Revision: https://reviews.llvm.org/D94098
This is part of a patch series working towards the ability to make
SourceLocation into a 64-bit type to handle larger translation units.
!srcloc is generated in clang codegen, and pulled back out by llvm
functions like AsmPrinter::emitInlineAsm that need to report errors in
the inline asm. From there it goes to LLVMContext::emitError, is
stored in DiagnosticInfoInlineAsm, and ends up back in clang, at
BackendConsumer::InlineAsmDiagHandler(), which reconstitutes a true
clang::SourceLocation from the integer cookie.
Throughout this code path, it's now 64-bit rather than 32, which means
that if SourceLocation is expanded to a 64-bit type, this error report
won't lose half of the data.
The compiler will tolerate both of i32 and i64 !srcloc metadata in
input IR without faulting. Test added in llvm/MC. (The semantic
accuracy of the metadata is another matter, but I don't know of any
situation where that matters: if you're reading an IR file written by
a previous run of clang, you don't have the SourceManager that can
relate those source locations back to the original source files.)
Original version of the patch by Mikhail Maltsev.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D105491
This change is intended as initial setup. The plan is to add
more semantic checks later. I plan to update the documentation
as more semantic checks are added (instead of documenting the
details up front). Most of the code closely mirrors that for
the Swift calling convention. Three places are marked as
[FIXME: swiftasynccc]; those will be addressed once the
corresponding convention is introduced in LLVM.
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D95561
