maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[GlobalISel][IRTranslator] Move line zero DebugLoc creation to constant translation. NFC. 

This is a compile time optimization. DILocation:get() is expensive to call, and
we were calling it to create a line zero debug loc for *every* instruction we
translated. We only really need to do this just before we build constants in the
entry block, so I moved this code there. This reduces the LLVM -O0 codegen time
of sqlite3 IR by around 0.7% instructions executed and by about ~2% in CPU time.

We can probably do better with a more involved change, since the reason we need
to create one for each new constant is because we're using the debug scope and
inlined-at loc. If we just use a single instruction's scope and drop the
inlined-at, we can just cache these and have them be free.
This commit is contained in:
Amara Emerson 2021-04-28 23:16:54 -07:00
parent 465df35355
commit aa0b9200e8
1 changed files with 9 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
View File

@ -2842,13 +2842,6 @@ bool IRTranslator::valueIsSplit(const Value &V,
bool IRTranslator::translate(const Instruction &Inst) {
CurBuilder->setDebugLoc(Inst.getDebugLoc());
// We only emit constants into the entry block from here. To prevent jumpy
// debug behaviour set the line to 0.
if (const DebugLoc &DL = Inst.getDebugLoc())
EntryBuilder->setDebugLoc(DILocation::get(
Inst.getContext(), 0, 0, DL.getScope(), DL.getInlinedAt()));
else
EntryBuilder->setDebugLoc(DebugLoc());
auto &TLI = *MF->getSubtarget().getTargetLowering();
if (TLI.fallBackToDAGISel(Inst))
@ -2865,6 +2858,15 @@ bool IRTranslator::translate(const Instruction &Inst) {
}
bool IRTranslator::translate(const Constant &C, Register Reg) {
// We only emit constants into the entry block from here. To prevent jumpy
// debug behaviour set the line to 0.
if (auto CurrInstDL = CurBuilder->getDL())
EntryBuilder->setDebugLoc(DILocation::get(C.getContext(), 0, 0,
CurrInstDL.getScope(),
CurrInstDL.getInlinedAt()));
else
EntryBuilder->setDebugLoc(DebugLoc());
if (auto CI = dyn_cast<ConstantInt>(&C))
EntryBuilder->buildConstant(Reg, *CI);
else if (auto CF = dyn_cast<ConstantFP>(&C))