If some commits are happy, and some commits are sad, this is a sad commit. It
is sad because it restricts instruction scheduling to work around a binutils
linker bug, and moreover, one that may never be fixed. On 2012-05-21, GCC was
updated not to produce code triggering this bug, and now we'll do the same...
When resolving an address using the ELF ABI TOC pointer, two relocations are
generally required: one for the high part and one for the low part. Only
the high part generally explicitly depends on r2 (the TOC pointer). And, so,
we might produce code like this:
.Ltmp526:
addis 3, 2, .LC12@toc@ha
.Ltmp1628:
std 2, 40(1)
ld 5, 0(27)
ld 2, 8(27)
ld 11, 16(27)
ld 3, .LC12@toc@l(3)
rldicl 4, 4, 0, 32
mtctr 5
bctrl
ld 2, 40(1)
And there is nothing wrong with this code, as such, but there is a linker bug
in binutils (https://sourceware.org/bugzilla/show_bug.cgi?id=18414) that will
misoptimize this code sequence to this:
nop
std r2,40(r1)
ld r5,0(r27)
ld r2,8(r27)
ld r11,16(r27)
ld r3,-32472(r2)
clrldi r4,r4,32
mtctr r5
bctrl
ld r2,40(r1)
because the linker does not know (and does not check) that the value in r2
changed in between the instruction using the .LC12@toc@ha (TOC-relative)
relocation and the instruction using the .LC12@toc@l(3) relocation.
Because it finds these instructions using the relocations (and not by
scanning the instructions), it has been asserted that there is no good way
to detect the change of r2 in between. As a result, this bug may never be
fixed (i.e. it may become part of the definition of the ABI). GCC was
updated to add extra dependencies on r2 to instructions using the @toc@l
relocations to avoid this problem, and we'll do the same here.
This is done as a separate pass because:
1. These extra r2 dependencies are not really properties of the
instructions, but rather due to a linker bug, and maybe one day we'll be
able to get rid of them when targeting linkers without this bug (and,
thus, keeping the logic centralized here will make that
straightforward).
2. There are ISel-level peephole optimizations that propagate the @toc@l
relocations to some user instructions, and so the exta dependencies do
not apply only to a fixed set of instructions (without undesirable
definition replication).
The test case was reduced with the help of bugpoint, with minimal cleaning. I'm
looking forward to our upcoming MI serialization support, and with that, much
better tests can be created.
llvm-svn: 237556
Summary:
But still handle them the same way since I don't know how they differ on
this target.
Of these, 'o' and 'v' are not tested but were already implemented.
I'm not sure why 'i' is required for X86 since it's supposed to be an
immediate constraint rather than a memory constraint. A test asserts
without it so I've included it for now.
No functional change intended.
Reviewers: nadav
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8254
llvm-svn: 237517
This patch adds support for the following new instructions in the
Power ISA 2.07:
vpksdss
vpksdus
vpkudus
vpkudum
vupkhsw
vupklsw
These instructions are available through the vec_packs, vec_packsu,
vec_unpackh, and vec_unpackl built-in interfaces. These are
lane-sensitive instructions, so the built-ins have different
implementations for big- and little-endian, and the instructions must
be marked as killing the vector swap optimization for now.
The first three instructions perform saturating pack operations. The
fourth performs a modulo pack operation, which means it can be
represented with a vector shuffle, and conversely the appropriate
vector shuffles may cause this instruction to be generated. The other
instructions are only generated via built-in support for now.
Appropriate tests have been added.
There is a companion patch to clang for the rest of this support.
llvm-svn: 237499
Other pieces of CodeGen want to negate frame object offsets to account
for architectures where the stack grows down. Our object is a pseudo
object so it's offset doesn't matter. However, we shouldn't choose an
offset which results in undefined behavior if you negate it.
llvm-svn: 237474
Summary:
To maintain compatibility with GAS, we need to stop treating negative 32-bit immediates as 64-bit values when expanding LI/DLI.
This currently happens because of sign extension.
To do this we need to choose the 32-bit value expansion for values which use their upper 33 bits only for sign extension (i.e. no 0's, only 1's).
Reviewers: dsanders
Reviewed By: dsanders
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8662
llvm-svn: 237428
Instead of doing that, create a temporary copy of MCTargetOptions and reset its
SanitizeAddress field based on the function's attribute every time an InlineAsm
instruction is emitted in AsmPrinter::EmitInlineAsm.
This is part of the work to remove TargetMachine::resetTargetOptions (the FIXME
added to TargetMachine.cpp in r236009 explains why this function has to be
removed).
Differential Revision: http://reviews.llvm.org/D9570
llvm-svn: 237412
The induction variable in the vectorized loop wasn't
recognized properly, so a hardware loop wasn't generated.
Differential Revision: http://reviews.llvm.org/D9722
llvm-svn: 237388
After converting a loop to a hardware loop, the pass should remove
any unnecessary instructions from the old compare-and-branch
code. This patch removes a dead constant assignment that was
used in the compare instruction.
Differential Revision: http://reviews.llvm.org/D9720
llvm-svn: 237373
If the loop trip count may underflow or wrap, the compiler should
not generate a hardware loop since the trip count will be
incorrect.
llvm-svn: 237365
Summary:
When we are trying to fill the delay slot of a call instruction, we must avoid
filler instructions that use the $ra register. This fixes the test
MultiSource/Applications/JM/lencod when we enable the forward delay slot filler.
Reviewers: dsanders
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9670
llvm-svn: 237362
Summary:
If we only pass the necessary operands, we don't have to determine the position of the symbol operand when entering expandLoadAddressSym().
This simplifies the expandLoadAddressSym() code.
Reviewers: dsanders
Reviewed By: dsanders
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9291
llvm-svn: 237355
i1 type is a legal type on AVX-512 and can be passed as parameter or return value.
i1 is promoted to i8 on return and to i32 for call arguments (i8 is also promoted to i32 here).
The result code is similar to the previous X86 targets, where i1 is allways promoted to i8.
llvm-svn: 237350
There's no need to manually pass modifier strings around to tell an operand how
to print now, that information is encoded in the operand itself since the MC
layer came along.
llvm-svn: 237295
We were creating and propagating two separate indices for each jump table (from
back in the mists of time). However, the generic index used by other backends
is sufficient to emit a unique symbol so this was unneeded.
llvm-svn: 237294
The previous logic mixed 2 separate questions:
+ Can we form a TBB/TBH instruction?
+ Can we remove the jump-table calculation before it?
It then performed a bunch of random tests on the instructions earlier in the
basic block, which were probably sufficient to answer 2 but only because of the
very limited ways in which a t2BR_JT can actually be created.
For example there's no reason to expect the LeaInst to define the same base
register as the following indexing calulation. In practice this means we might
have missed opportunities to form TBB/TBH, in theory you could end up
misidentifying a sequence and removing the wrong LEA:
%R1 = t2LEApcrelJT ...
%R2 = t2LEApcrelJT ...
<... using and killing %R2 ...>
%R2 = t2ADDr %R1, $Ridx
Before we would have looked for an LEA defining %R2 and found the wrong one. We
just got lucky that jump table setup was (almost?) always confined to a single
basic block and there was only one jump table per block.
llvm-svn: 237293
Some compilers warn about using the ternary operator with an unsigned variable
and enum.
I haven't seen this trigger in the llvm.org buildbots yet, but it probably will
at some point.
Reported by Daniel Sanders.
llvm-svn: 237262
The hardware loop pass should try to generate a hardware loop
instruction when the original loop has a critical edge.
Differential Revision: http://reviews.llvm.org/D9678
llvm-svn: 237258
Summary: A side-effect of this is that LA gains proper handling of unsigned and positive signed 16-bit immediates and more accurate error messages.
Reviewers: dsanders
Reviewed By: dsanders
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9290
llvm-svn: 237255
Previously, subtarget features were a bitfield with the underlying type being uint64_t.
Since several targets (X86 and ARM, in particular) have hit or were very close to hitting this bound, switching the features to use a bitset.
No functional change.
The first two times this was committed (r229831, r233055), it caused several buildbot failures.
At least some of the ARM and MIPS ones were due to gcc/binutils issues, and should now be fixed.
llvm-svn: 237234
Summary:
This change adds two new parameters to the statepoint intrinsic, `i64 id`
and `i32 num_patch_bytes`. `id` gets propagated to the ID field
in the generated StackMap section. If the `num_patch_bytes` is
non-zero then the statepoint is lowered to `num_patch_bytes` bytes of
nops instead of a call (the spill and reload code remains unchanged).
A non-zero `num_patch_bytes` is useful in situations where a language
runtime requires complete control over how a call is lowered.
This change brings statepoints one step closer to patchpoints. With
some additional work (that is not part of this patch) it should be
possible to get rid of `TargetOpcode::STATEPOINT` altogether.
PlaceSafepoints generates `statepoint` wrappers with `id` set to
`0xABCDEF00` (the old default value for the ID reported in the stackmap)
and `num_patch_bytes` set to `0`. This can be made more sophisticated
later.
Reviewers: reames, pgavlin, swaroop.sridhar, AndyAyers
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9546
llvm-svn: 237214
