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0792e8ab30
This patch fixes the latency/throughput of LEA instructions in the BtVer2
scheduling model.
On Jaguar, A 3-operands LEA has a latency of 2cy, and a reciprocal throughput of
1. That is because it uses one cycle of SAGU followed by 1cy of ALU1. An LEA
with a "Scale" operand is also slow, and it has the same latency profile as the
3-operands LEA. An LEA16r has a latency of 3cy, and a throughput of 0.5 (i.e.
RThrouhgput of 2.0).
This patch adds a new TIIPredicate named IsThreeOperandsLEAFn to X86Schedule.td.
The tablegen backend (for instruction-info) expands that definition into this
(file X86GenInstrInfo.inc):
```
static bool isThreeOperandsLEA(const MachineInstr &MI) {
return (
(
MI.getOpcode() == X86::LEA32r
|| MI.getOpcode() == X86::LEA64r
|| MI.getOpcode() == X86::LEA64_32r
|| MI.getOpcode() == X86::LEA16r
)
&& MI.getOperand(1).isReg()
&& MI.getOperand(1).getReg() != 0
&& MI.getOperand(3).isReg()
&& MI.getOperand(3).getReg() != 0
&& (
(
MI.getOperand(4).isImm()
&& MI.getOperand(4).getImm() != 0
)
|| (MI.getOperand(4).isGlobal())
)
);
}
```
A similar method is generated in the X86_MC namespace, and included into
X86MCTargetDesc.cpp (the declaration lives in X86MCTargetDesc.h).
Back to the BtVer2 scheduling model:
A new scheduling predicate named JSlowLEAPredicate now checks if either the
instruction is a three-operands LEA, or it is an LEA with a Scale value
different than 1.
A variant scheduling class uses that new predicate to correctly select the
appropriate latency profile.
Differential Revision: https://reviews.llvm.org/D49436
llvm-svn: 337469
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| dsymutil | ||
| gold | ||
| llvm-ar | ||
| llvm-cfi-verify | ||
| llvm-config | ||
| llvm-cov | ||
| llvm-cvtres | ||
| llvm-cxxdump | ||
| llvm-cxxfilt | ||
| llvm-diff | ||
| llvm-dlltool | ||
| llvm-dwarfdump | ||
| llvm-dwp | ||
| llvm-extract | ||
| llvm-isel-fuzzer | ||
| llvm-lib | ||
| llvm-lit | ||
| llvm-lto | ||
| llvm-lto2 | ||
| llvm-mc | ||
| llvm-mca | ||
| llvm-modextract | ||
| llvm-mt | ||
| llvm-nm | ||
| llvm-objcopy | ||
| llvm-objdump | ||
| llvm-opt-fuzzer | ||
| llvm-opt-report | ||
| llvm-pdbdump | ||
| llvm-profdata | ||
| llvm-rc | ||
| llvm-readobj | ||
| llvm-size | ||
| llvm-split | ||
| llvm-strings | ||
| llvm-symbolizer | ||
| llvm-xray/X86 | ||
| lto | ||
| obj2yaml | ||
| opt-viewer | ||
| sancov | ||
| sanstats | ||
| yaml2obj | ||