Skip to content

[X86] Ensure that bit reversals of byte vectors are properly lowered on pure GFNI targets #148304

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 6 commits into from
Jul 18, 2025
Merged

[X86] Ensure that bit reversals of byte vectors are properly lowered on pure GFNI targets #148304

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
3a15c6a
Fix #148238
TDecking Jul 11, 2025
d4194ec
Update the test file
TDecking Jul 18, 2025
c097e12
Extend the optimization towards other vectors
TDecking Jul 18, 2025
718deea
Turn SSSE2 into SSSE3
TDecking Jul 18, 2025
4f27cd7
Formatting
TDecking Jul 18, 2025
aaf7f6d
Merge branch 'main' into bitrev
RKSimon Jul 18, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 7 additions & 2 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1323,11 +1323,15 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
setOperationAction(ISD::STRICT_FDIV, MVT::v2f64, Legal);
}

if (Subtarget.hasGFNI()) {
if (!Subtarget.useSoftFloat() && Subtarget.hasGFNI()) {
setOperationAction(ISD::BITREVERSE, MVT::i8, Custom);
setOperationAction(ISD::BITREVERSE, MVT::i16, Custom);
setOperationAction(ISD::BITREVERSE, MVT::i32, Custom);
setOperationAction(ISD::BITREVERSE, MVT::i64, Custom);

for (auto VT : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v2i64}) {
setOperationAction(ISD::BITREVERSE, VT, Custom);
}
}

if (!Subtarget.useSoftFloat() && Subtarget.hasSSSE3()) {
Expand Down Expand Up @@ -32694,7 +32698,8 @@ static SDValue LowerBITREVERSE(SDValue Op, const X86Subtarget &Subtarget,
if (Subtarget.hasXOP() && !VT.is512BitVector())
return LowerBITREVERSE_XOP(Op, DAG);

assert(Subtarget.hasSSSE3() && "SSSE3 required for BITREVERSE");
assert((Subtarget.hasSSSE3() || Subtarget.hasGFNI()) &&
"SSSE3 or GFNI required for BITREVERSE");

SDValue In = Op.getOperand(0);
SDLoc DL(Op);
Expand Down
Loading
Loading