forked from OSchip/llvm-project
e7084ceab3
Sometimes we generate code that writes to a subregister, then spills /
restores a super-register to the stack, for example:
$eax = MOV32ri 0
MOV64mr $rsp, 1, $noreg, 16, $noreg, $rax
$rcx = MOV64rm $rsp, 1, $noreg, 8, $noreg
This patch takes a different approach: it adds another index to
MLocTracker that identifies a size/offset within a stack slot. A location
on the stack is then a pari of {FrameIndex, SlotNum}. Spilling and
restoring now involves pairing up the src/dest register numbers, and the
dest/src stack position to be transferred to/from. Location coverage
improves as a result, compile-time performance decreases, alas.
One limitation is that if a PHI occurs inside a stack slot:
DBG_PHI %stack.0, 1
We don't know how large the resulting value is, and so might have
difficulty picking which value to use. DBG_PHI might need to be augmented
in the future with such a size.
Unit tests added ensure that spills and restores correctly transfer to
positions in the Location => Value map, and that different register classes
written to the stack will correctly clobber all other positions in the
stack slot.
Differential Revision: https://reviews.llvm.org/D112133
|
||
|---|---|---|
| .. | ||
| GlobalISel | ||
| AArch64SelectionDAGTest.cpp | ||
| AllocationOrderTest.cpp | ||
| AsmPrinterDwarfTest.cpp | ||
| CMakeLists.txt | ||
| DIEHashTest.cpp | ||
| DIETest.cpp | ||
| InstrRefLDVTest.cpp | ||
| LexicalScopesTest.cpp | ||
| LowLevelTypeTest.cpp | ||
| MFCommon.inc | ||
| MachineInstrBundleIteratorTest.cpp | ||
| MachineInstrTest.cpp | ||
| MachineOperandTest.cpp | ||
| PassManagerTest.cpp | ||
| ScalableVectorMVTsTest.cpp | ||
| SelectionDAGAddressAnalysisTest.cpp | ||
| TargetOptionsTest.cpp | ||
| TestAsmPrinter.cpp | ||
| TestAsmPrinter.h | ||
| TypeTraitsTest.cpp | ||