accumulator instead of its sub-registers, $hi and $lo.
We need this change to prevent a mflo following a mtlo from reading an
unpredictable/undefined value, as shown in the following example:
mult $6, $7 // result of $6 * $7 is written to $lo and $hi.
mflo $2 // read lower 32-bit result from $lo.
mtlo $4 // write to $lo. the content of $hi becomes unpredictable.
mfhi $3 // read higher 32-bit from $hi, which has an unpredictable value.
I don't have a test case for this change that reliably reproduces the problem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192119 91177308-0d34-0410-b5e6-96231b3b80d8
The hint instructions ("nop", "yield", etc) are mostly Thumb2-only, but have
been ported across to the v6M architecture. Fortunately, v6M seems to sit
nicely between v6 (thumb-1 only) and v6T2, so we can add a feature for it
fairly easily.
rdar://problem/15144406
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192097 91177308-0d34-0410-b5e6-96231b3b80d8
This allows the instruction to be encoded using the 2-byte VEX form instead of the 3-byte VEX form. The GNU assembler has similar behavior and instruction selection already does this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192088 91177308-0d34-0410-b5e6-96231b3b80d8
Regalloc can emit unaligned spills nowadays, but we can't fold the
spills into SSE ops if we can't guarantee alignment. PR12250.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192064 91177308-0d34-0410-b5e6-96231b3b80d8
This is required because i64 is a legal type but addxcc/subxcc reads icc carry bit, which are 32 bit conditional codes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192054 91177308-0d34-0410-b5e6-96231b3b80d8
When MC was first added, targets could use hasRawTextSupport to keep features
working before they were added to the MC interface.
The design goal of MC is to provide an uniform api for printing assembly and
object files. Short of relaxations and other corner cases, a object file is
just another representation of the assembly.
It was never the intention that targets would keep doing things like
if (hasRawTextSupport())
Set flags in one way.
else
Set flags in another way.
When they do that they create two code paths and the object file is no longer
just another representation of the assembly. This also then requires testing
with llc -filetype=obj, which is extremelly brittle.
This patch removes some of these hacks by replacing them with smaller ones.
The ARM flag setting is trivial, so I just moved it to the constructor. For
Mips, the patch adds two temporary hack directives that allow the assembly
to represent the same things as the object file was already able to.
The hope is that the mips developers will replace the hack directives with
the same ones that gas uses and drop the -print-hack-directives flag.
I will also try to implement a target streamer interface, so that we can
move this out of the common code.
In summary, for any new work, two rules of the thumb are
* Don't use "llc -filetype=obj" in tests.
* Don't add calls to hasRawTextSupport.
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This patch handles LLVM standalone assembler (llvm-mc) ELF flag setting based on input file
directive processing.
Mips assembly requires processing inline directives that directly and
indirectly affect the output ELF header flags. This patch handles one
".abicalls".
To process these directives we are following the model the code generator
uses by storing state in a container as we go through processing and when
we detect the end of input file processing, AsmParser is notified and we
update the ELF header flags through a MipsELFStreamer method with a call from
MCTargetAsmParser::emitEndOfAsmFile(MCStreamer &OutStreamer).
This patch will allow other targets the same functionality.
Jack
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optimizeSelect folds (predicated) copy instructions, it must not ignore
the original register class of the operand when replacing the register
with the copies dest register.
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The jump doesn't really kill the registers, the following call does but
we never get back anyway.
This avoids some verify-machineinstrs problems when TAILJUMPs are
if-converted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191962 91177308-0d34-0410-b5e6-96231b3b80d8
Copy over the whole register machine operand instead of creating a new one
with an incomplete set of flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191961 91177308-0d34-0410-b5e6-96231b3b80d8
