The current PowerPC MC back end distinguishes between fixup_ppc_ha16
and fixup_ppc_lo16, which are determined by the instruction the fixup
applies to, and uses this distinction to decide whether a fixup ought
to resolve to the high or the low part of a symbol address.
This isn't quite correct, however. It is valid -if unusual- assembler
to use, e.g.
li 1, symbol@ha
or
lis 1, symbol@l
Whether the high or the low part of the address is used depends solely
on the @ suffix, not on the instruction.
In addition, both
li 1, symbol
and
lis 1, symbol
are valid, assuming the symbol address fits into 16 bits; again, both
will then refer to the actual symbol value (so li will load the value
itself, while lis will load the value shifted by 16).
To fix this, two places need to be adapted. If the fixup cannot be
resolved at assembler time, a relocation needs to be emitted via
PPCELFObjectWriter::getRelocType. This routine already looks at
the VK_ type to determine the relocation. The only problem is that
will reject any _LO modifier in a ha16 fixup and vice versa. This
is simply incorrect; any of those modifiers ought to be accepted
for either fixup type.
If the fixup *can* be resolved at assembler time, adjustFixupValue
currently selects the high bits of the symbol value if the fixup
type is ha16. Again, this is incorrect; see the above example
lis 1, symbol
Now, in theory we'd have to respect a VK_ modifier here. However,
in fact common code never even attempts to resolve symbol references
using any nontrivial VK_ modifier at assembler time; it will always
fall back to emitting a reloc and letting the linker handle it.
If this ever changes, presumably there'd have to be a target callback
to resolve VK_ modifiers. We'd then have to handle @ha etc. there.
llvm-svn: 182091
This is a candidate for the stable branch.
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=64694
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
llvm-svn: 182084
Previously, three instructions were needed:
trunc.w.s $f0, $f2
mfc1 $4, $f0
sw $4, 0($2)
Now we need only two:
trunc.w.s $f0, $f2
swc1 $f0, 0($2)
llvm-svn: 182053
This patch removes alias definition for addiu $rs,$imm
and instead uses the TwoOperandAliasConstraint field in
the ArithLogicI instruction class.
This way all instructions that inherit ArithLogicI class
have the same macro defined.
The usage examples are added to test files.
Patch by Vladimir Medic
llvm-svn: 182048
Some IR-level instructions (such as FP <-> i64 conversions) are not chained
w.r.t. the mtctr intrinsic and yet may become function calls that clobber the
counter register. At the selection-DAG level, these might be reordered with the
mtctr intrinsic causing miscompiles. To avoid this situation, if an existing
preheader has instructions that might use the counter register, create a new
preheader for the mtctr intrinsic. This extra block will be remerged with the
old preheader at the MI level, but will prevent unwanted reordering at the
selection-DAG level.
llvm-svn: 182045
invalid instruction sequence.
Rather than emitting an int-to-FP move instruction and an int-to-FP conversion
instruction during instruction selection, we emit a pseudo instruction which gets
expanded post-RA. Without this change, register allocation can possibly insert a
floating point register move instruction between the two instructions, which is not
valid according to the ISA manual.
mtc1 $f4, $4 # int-to-fp move instruction.
mov.s $f2, $f4 # move contents of $f4 to $f2.
cvt.s.w $f0, $f2 # int-to-fp conversion.
llvm-svn: 182042
This patch adds bnez and beqz instructions which represent alias definitions for bne and beq instructions as follows:
bnez $rs,$imm => bne $rs,$zero,$imm
beqz $rs,$imm => beq $rs,$zero,$imm
The corresponding test cases are added.
Patch by Vladimir Medic
llvm-svn: 182040
This lane mask provides information about which register lanes
completely cover super-registers. See the block comment before
getCoveringLanes().
llvm-svn: 182034
This is the second part of the change to always return "true"
offset values from getPreIndexedAddressParts, tackling the
case of "memrix" type operands.
This is about instructions like LD/STD that only have a 14-bit
field to encode immediate offsets, which are implicitly extended
by two zero bits by the machine, so that in effect we can access
16-bit offsets as long as they are a multiple of 4.
The PowerPC back end currently handles such instructions by
carrying the 14-bit value (as it will get encoded into the
actual machine instructions) in the machine operand fields
for such instructions. This means that those values are
in fact not the true offset, but rather the offset divided
by 4 (and then truncated to an unsigned 14-bit value).
Like in the case fixed in r182012, this makes common code
operations on such offset values not work as expected.
Furthermore, there doesn't really appear to be any strong
reason why we should encode machine operands this way.
This patch therefore changes the encoding of "memrix" type
machine operands to simply contain the "true" offset value
as a signed immediate value, while enforcing the rules that
it must fit in a 16-bit signed value and must also be a
multiple of 4.
This change must be made simultaneously in all places that
access machine operands of this type. However, just about
all those changes make the code simpler; in many cases we
can now just share the same code for memri and memrix
operands.
llvm-svn: 182032
While testing some experimental code to add vector-scalar registers to
PowerPC, I noticed that a couple of independent instructions were
flipped by the scheduler. The new CHECK-DAG support is perfect for
avoiding this problem.
llvm-svn: 182020
DAGCombiner::CombineToPreIndexedLoadStore calls a target routine to
decompose a memory address into a base/offset pair. It expects the
offset (if constant) to be the true displacement value in order to
perform optional additional optimizations; in particular, to convert
other uses of the original pointer into uses of the new base pointer
after pre-increment.
The PowerPC implementation of getPreIndexedAddressParts, however,
simply calls SelectAddressRegImm, which returns a TargetConstant.
This value is appropriate for encoding into the instruction, but
it is not always usable as true displacement value:
- Its type is always MVT::i32, even on 64-bit, where addresses
ought to be i64 ... this causes the optimization to simply
always fail on 64-bit due to this line in DAGCombiner:
// FIXME: In some cases, we can be smarter about this.
if (Op1.getValueType() != Offset.getValueType()) {
- Its value is truncated to an unsigned 16-bit value if negative.
This causes the above opimization to generate wrong code.
This patch fixes both problems by simply returning the true
displacement value (in its original type). This doesn't
affect any other user of the displacement.
llvm-svn: 182012
getExceptionHandlingType is not ExceptionHandling::DwarfCFI on xcore, so
etFrameInstructions is never called. There is no point creating cfi
instructions if they are never used.
llvm-svn: 181979
Without this change nothing was covering this addFrameMove:
// For 64-bit SVR4 when we have spilled CRs, the spill location
// is SP+8, not a frame-relative slot.
if (Subtarget.isSVR4ABI()
&& Subtarget.isPPC64()
&& (PPC::CR2 <= Reg && Reg <= PPC::CR4)) {
MachineLocation CSDst(PPC::X1, 8);
MachineLocation CSSrc(PPC::CR2);
MMI.addFrameMove(Label, CSDst, CSSrc);
continue;
}
llvm-svn: 181976
This creates stubs that help Mips32 functions call Mips16
functions which have floating point parameters that are normally passed
in floating point registers.
llvm-svn: 181972
