[InstCombine] refactor folds for (icmp (bitcast X), Y); NFCI
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353462 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 399aa2d..5a63d55 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2490,20 +2490,72 @@
// the entire original Cmp can be simplified to a false.
Value *Cond = Builder.getFalse();
if (TrueWhenLessThan)
- Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SLT, OrigLHS, OrigRHS));
+ Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SLT,
+ OrigLHS, OrigRHS));
if (TrueWhenEqual)
- Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_EQ, OrigLHS, OrigRHS));
+ Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_EQ,
+ OrigLHS, OrigRHS));
if (TrueWhenGreaterThan)
- Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SGT, OrigLHS, OrigRHS));
+ Cond = Builder.CreateOr(Cond, Builder.CreateICmp(ICmpInst::ICMP_SGT,
+ OrigLHS, OrigRHS));
return replaceInstUsesWith(Cmp, Cond);
}
return nullptr;
}
-Instruction *InstCombiner::foldICmpBitCastConstant(ICmpInst &Cmp,
- BitCastInst *Bitcast,
- const APInt &C) {
+static Instruction *foldICmpBitCast(ICmpInst &Cmp,
+ InstCombiner::BuilderTy &Builder) {
+ auto *Bitcast = dyn_cast<BitCastInst>(Cmp.getOperand(0));
+ if (!Bitcast)
+ return nullptr;
+
+ // Zero-equality and sign-bit checks are preserved through sitofp + bitcast.
+ // FIXME: This needs to check that the bitcast does not change the number of
+ // elements in a vector.
+ ICmpInst::Predicate Pred = Cmp.getPredicate();
+ Value *Op1 = Cmp.getOperand(1);
+ Value *BCSrcOp = Bitcast->getOperand(0);
+ Value *X;
+ if (match(BCSrcOp, m_SIToFP(m_Value(X)))) {
+ // icmp eq (bitcast (sitofp X)), 0 --> icmp eq X, 0
+ // icmp ne (bitcast (sitofp X)), 0 --> icmp ne X, 0
+ // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0
+ // icmp sgt (bitcast (sitofp X)), 0 --> icmp sgt X, 0
+ if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_SLT ||
+ Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT) &&
+ match(Op1, m_Zero()))
+ return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
+
+ // icmp slt (bitcast (sitofp X)), 1 --> icmp slt X, 1
+ if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_One()))
+ return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), 1));
+
+ // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1
+ if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))
+ return new ICmpInst(Pred, X, ConstantInt::getAllOnesValue(X->getType()));
+ }
+
+ // Zero-equality checks are preserved through unsigned floating-point casts:
+ // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0
+ // icmp ne (bitcast (uitofp X)), 0 --> icmp ne X, 0
+ if (match(BCSrcOp, m_UIToFP(m_Value(X))))
+ if (Cmp.isEquality() && match(Op1, m_Zero()))
+ return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
+
+ // Test to see if the operands of the icmp are casted versions of other
+ // values. If the ptr->ptr cast can be stripped off both arguments, do so.
+ if (Bitcast->getType()->isPointerTy() &&
+ (isa<Constant>(Op1) || isa<BitCastInst>(Op1))) {
+ // If operand #1 is a bitcast instruction, it must also be a ptr->ptr cast
+ // so eliminate it as well.
+ if (auto *BC2 = dyn_cast<BitCastInst>(Op1))
+ Op1 = BC2->getOperand(0);
+
+ Op1 = Builder.CreateBitCast(Op1, BCSrcOp->getType());
+ return new ICmpInst(Pred, BCSrcOp, Op1);
+ }
+
// Folding: icmp <pred> iN X, C
// where X = bitcast <M x iK> (shufflevector <M x iK> %vec, undef, SC)) to iN
// and C is a splat of a K-bit pattern
@@ -2511,28 +2563,28 @@
// Into:
// %E = extractelement <M x iK> %vec, i32 C'
// icmp <pred> iK %E, trunc(C)
- if (!Bitcast->getType()->isIntegerTy() ||
+ const APInt *C;
+ if (!match(Cmp.getOperand(1), m_APInt(C)) ||
+ !Bitcast->getType()->isIntegerTy() ||
!Bitcast->getSrcTy()->isIntOrIntVectorTy())
return nullptr;
- Value *BCIOp = Bitcast->getOperand(0);
- Value *Vec = nullptr; // 1st vector arg of the shufflevector
- Constant *Mask = nullptr; // Mask arg of the shufflevector
- if (match(BCIOp,
+ Value *Vec;
+ Constant *Mask;
+ if (match(BCSrcOp,
m_ShuffleVector(m_Value(Vec), m_Undef(), m_Constant(Mask)))) {
// Check whether every element of Mask is the same constant
if (auto *Elem = dyn_cast_or_null<ConstantInt>(Mask->getSplatValue())) {
- auto *VecTy = cast<VectorType>(BCIOp->getType());
+ auto *VecTy = cast<VectorType>(BCSrcOp->getType());
auto *EltTy = cast<IntegerType>(VecTy->getElementType());
- auto Pred = Cmp.getPredicate();
- if (C.isSplat(EltTy->getBitWidth())) {
+ if (C->isSplat(EltTy->getBitWidth())) {
// Fold the icmp based on the value of C
// If C is M copies of an iK sized bit pattern,
// then:
// => %E = extractelement <N x iK> %vec, i32 Elem
// icmp <pred> iK %SplatVal, <pattern>
Value *Extract = Builder.CreateExtractElement(Vec, Elem);
- Value *NewC = ConstantInt::get(EltTy, C.trunc(EltTy->getBitWidth()));
+ Value *NewC = ConstantInt::get(EltTy, C->trunc(EltTy->getBitWidth()));
return new ICmpInst(Pred, Extract, NewC);
}
}
@@ -2614,11 +2666,6 @@
return I;
}
- if (auto *BCI = dyn_cast<BitCastInst>(Cmp.getOperand(0))) {
- if (Instruction *I = foldICmpBitCastConstant(Cmp, BCI, *C))
- return I;
- }
-
if (auto *II = dyn_cast<IntrinsicInst>(Cmp.getOperand(0)))
if (Instruction *I = foldICmpIntrinsicWithConstant(Cmp, II, *C))
return I;
@@ -4945,61 +4992,8 @@
return New;
}
- // Zero-equality and sign-bit checks are preserved through sitofp + bitcast.
- Value *X;
- if (match(Op0, m_BitCast(m_SIToFP(m_Value(X))))) {
- // icmp eq (bitcast (sitofp X)), 0 --> icmp eq X, 0
- // icmp ne (bitcast (sitofp X)), 0 --> icmp ne X, 0
- // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0
- // icmp sgt (bitcast (sitofp X)), 0 --> icmp sgt X, 0
- if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_SLT ||
- Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT) &&
- match(Op1, m_Zero()))
- return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
-
- // icmp slt (bitcast (sitofp X)), 1 --> icmp slt X, 1
- if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_One()))
- return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), 1));
-
- // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1
- if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))
- return new ICmpInst(Pred, X, ConstantInt::getAllOnesValue(X->getType()));
- }
-
- // Zero-equality checks are preserved through unsigned floating-point casts:
- // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0
- // icmp ne (bitcast (uitofp X)), 0 --> icmp ne X, 0
- if (match(Op0, m_BitCast(m_UIToFP(m_Value(X)))))
- if (I.isEquality() && match(Op1, m_Zero()))
- return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
-
- // Test to see if the operands of the icmp are casted versions of other
- // values. If the ptr->ptr cast can be stripped off both arguments, we do so
- // now.
- if (BitCastInst *CI = dyn_cast<BitCastInst>(Op0)) {
- if (Op0->getType()->isPointerTy() &&
- (isa<Constant>(Op1) || isa<BitCastInst>(Op1))) {
- // We keep moving the cast from the left operand over to the right
- // operand, where it can often be eliminated completely.
- Op0 = CI->getOperand(0);
-
- // If operand #1 is a bitcast instruction, it must also be a ptr->ptr cast
- // so eliminate it as well.
- if (BitCastInst *CI2 = dyn_cast<BitCastInst>(Op1))
- Op1 = CI2->getOperand(0);
-
- // If Op1 is a constant, we can fold the cast into the constant.
- if (Op0->getType() != Op1->getType()) {
- if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
- Op1 = ConstantExpr::getBitCast(Op1C, Op0->getType());
- } else {
- // Otherwise, cast the RHS right before the icmp
- Op1 = Builder.CreateBitCast(Op1, Op0->getType());
- }
- }
- return new ICmpInst(I.getPredicate(), Op0, Op1);
- }
- }
+ if (Instruction *Res = foldICmpBitCast(I, Builder))
+ return Res;
if (isa<CastInst>(Op0)) {
// Handle the special case of: icmp (cast bool to X), <cst>
diff --git a/lib/Transforms/InstCombine/InstCombineInternal.h b/lib/Transforms/InstCombine/InstCombineInternal.h
index 35876a6..11993a4 100644
--- a/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -865,8 +865,6 @@
Instruction *foldICmpSelectConstant(ICmpInst &Cmp, SelectInst *Select,
ConstantInt *C);
- Instruction *foldICmpBitCastConstant(ICmpInst &Cmp, BitCastInst *Bitcast,
- const APInt &C);
Instruction *foldICmpTruncConstant(ICmpInst &Cmp, TruncInst *Trunc,
const APInt &C);
Instruction *foldICmpAndConstant(ICmpInst &Cmp, BinaryOperator *And,
