When calling SimplifyDemandedBits (as opposed to
SimplifyDemandedInstructionBits), and there are multiple uses,
always use SimplifyMultipleUseDemandedBits and drop the special
case for root values.
This fixes the ephemeral value detection, as seen by the restored
assumes in tests. It may result in more or less simplification,
depending on whether we get more out of having demanded bits or
the ability to perform non-multi-use transforms. The change in
the phi-known-bits.ll test is because the icmp operand now gets
simplified based on demanded bits, which then prevents a different
known bits simplification later.
This also makes the code safe against future changes like
https://github.com/llvm/llvm-project/pull/97289, which add more
context that would have to be discarded for the multi-use case.
Repplied with a clang test fix.
-----
When simplifying a multi-use root value, the demanded bits were
reset to full, but we also need to reset the context instruction.
To make this convenient (without requiring by-value passing of
SimplifyQuery), move the logic that handles constants and
dispatches to SimplifyDemandedUseBits/SimplifyMultipleUseDemandedBits
into SimplifyDemandedBits. The SimplifyDemandedInstructionBits
caller starts with full demanded bits and an appropriate context
anyway.
The different context instruction does mean that the ephemeral
value protection no longer triggers in some cases, as the changes
to assume tests show.
An alternative, which I will explore in a followup, is to always
use SimplifyMultipleUseDemandedBits() -- the previous root special
case is only really intended for SimplifyDemandedInstructionBits(),
which now no longer shares this code path.
Fixes https://github.com/llvm/llvm-project/issues/97330.
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
This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.
The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.
Differential Revision: https://reviews.llvm.org/D123115
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the eleventh batch of tests being updated (there are a
significant number of other tests left to be updated).
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
