On Nehalem and newer CPUs there is a 2 cycle latency penalty on using a register
in a different domain than where it was defined. Some instructions have
equvivalents for different domains, like por/orps/orpd.
The SSEDomainFix pass tries to minimize the number of domain crossings by
changing between equvivalent opcodes where possible.
This is a work in progress, in particular the pass doesn't do anything yet. SSE
instructions are tagged with their execution domain in TableGen using the last
two bits of TSFlags. Note that not all instructions are tagged correctly. Life
just isn't that simple.
The SSE execution domain issue is very similar to the ARM NEON/VFP pipeline
issue handled by NEONMoveFixPass. This pass may become target independent to
handle both.
llvm-svn: 99524
addl $12, %esp
popl %esi
popl %edi
popl %ebx
popl %ebp
jmpl *__Block_deallocator-L1$pb(%esi) # TAILCALL
The problem is the global base register is assigned GR32 register class. TCRETURNmi needs the registers making up the address mode to have the GR32_TC register class.
The *proper* fix is for X86DAGToDAGISel::getGlobalBaseReg() to return a copy from the global base register of the machine function rather than returning the register itself. But that has the potential of causing it to be coalesced to a more restrictive register class: GR32_TC. It can introduce additional copies and spills. For something as important the PIC base, it's not worth it especially since this is not an issue on 64-bit.
llvm-svn: 99455
--- Reverse-merging r99440 into '.':
U test/MC/AsmParser/X86/x86_32-bit_cat.s
U test/MC/AsmParser/X86/x86_32-encoding.s
U include/llvm/IntrinsicsX86.td
U include/llvm/CodeGen/SelectionDAGNodes.h
U lib/Target/X86/X86InstrSSE.td
U lib/Target/X86/X86ISelLowering.h
llvm-svn: 99450
not get an "Unknown immediate size" assert failure when used. All instructions
of this form have an 8-bit immediate. Also added a test case of an example
instruction that is of this form.
llvm-svn: 99435
ISD node. The only change in the generated isel code are comments
like:
< // Src: (X86dec_flag:i16 GR16:i16:$src)
---
> // Src: (X86dec_flag:i16:i32 GR16:i16:$src)
because now it knows that X86dec_flag returns both an i16 (for the result)
and an i32 (for EFLAGS) in this case. Wewt.
llvm-svn: 99369
This is work in progress. So far, SSE execution domain tables are added to
X86InstrInfo, and a skeleton pass is enabled with -sse-domain-fix.
llvm-svn: 99345
These instructions are only needed for codegen, so I've removed all the
explicit encoding bits for now; they should be set in the same way as the for
VLDMD and VSTMD whenever we add encodings for VFP. The use of addrmode5
requires that the instructions be custom-selected so that the number of
registers can be set in the AM5Opc value.
llvm-svn: 99309
Johnny Chen