RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-19 02:52:53 +02:00
Code Issues Projects Releases Wiki Activity

[InstCombine] allow vector splats for add+xor with low-mask

Browse Source 
This can be allowed with undef elements too, but that can be another step:
https://alive2.llvm.org/ce/z/hnC4Z-
This commit is contained in:
Sanjay Patel 2020-10-08 15:49:55 -04:00
parent 405a6508c3
commit 43799dbe92
2 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
lib/Transforms/InstCombine/InstCombineAddSub.cpp
View File

@ -924,9 +924,19 @@ Instruction *InstCombinerImpl::foldAddWithConstant(BinaryOperator &Add) {
C2->isMinSignedValue() && C2->sext(Ty->getScalarSizeInBits()) == *C)
return CastInst::Create(Instruction::SExt, X, Ty);
// (X ^ signmask) + C --> (X + (signmask ^ C))
if (match(Op0, m_Xor(m_Value(X), m_APInt(C2))) && C2->isSignMask())
return BinaryOperator::CreateAdd(X, ConstantInt::get(Ty, *C2 ^ *C));
if (match(Op0, m_Xor(m_Value(X), m_APInt(C2)))) {
// (X ^ signmask) + C --> (X + (signmask ^ C))
if (C2->isSignMask())
return BinaryOperator::CreateAdd(X, ConstantInt::get(Ty, *C2 ^ *C));
// If X has no high-bits set above an xor mask:
// add (xor X, LowMaskC), C --> sub (LowMaskC + C), X
if (C2->isMask()) {
KnownBits LHSKnown = computeKnownBits(X, 0, &Add);
if ((*C2 | LHSKnown.Zero).isAllOnesValue())
return BinaryOperator::CreateSub(ConstantInt::get(Ty, *C2 + *C), X);
}
}
if (C->isOneValue() && Op0->hasOneUse()) {
// add (sext i1 X), 1 --> zext (not X)
@ -1295,15 +1305,6 @@ Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) {
Value *NewShl = Builder.CreateShl(XorLHS, ShAmt, "sext");
return BinaryOperator::CreateAShr(NewShl, ShAmt);
}
// If X has no high-bits above the xor mask set:
// add (xor X, LowMaskC), C --> sub (LowMaskC + C), X
if ((XorRHS->getValue() + 1).isPowerOf2()) {
KnownBits LHSKnown = computeKnownBits(XorLHS, 0, &I);
if ((XorRHS->getValue() | LHSKnown.Zero).isAllOnesValue())
return BinaryOperator::CreateSub(ConstantExpr::getAdd(XorRHS, CI),
XorLHS);
}
}
}

3
test/Transforms/InstCombine/sub-xor.ll
View File

@ -68,8 +68,7 @@ define i32 @xor_add_extra_use(i32 %x) {
define <2 x i8> @xor_add_splat(<2 x i8> %x) {
; CHECK-LABEL: @xor_add_splat(
; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[X:%.*]], <i8 24, i8 24>
; CHECK-NEXT: [[XOR:%.*]] = xor <2 x i8> [[AND]], <i8 63, i8 63>
; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw <2 x i8> [[XOR]], <i8 42, i8 42>
; CHECK-NEXT: [[ADD:%.*]] = sub nuw nsw <2 x i8> <i8 105, i8 105>, [[AND]]
; CHECK-NEXT: ret <2 x i8> [[ADD]]
;
%and = and <2 x i8> %x, <i8 24, i8 24>