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-rw-r--r--llvm/include/llvm/Target/TargetLowering.h10
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp14
-rw-r--r--llvm/lib/Target/AArch64/AArch64ISelLowering.cpp4
-rw-r--r--llvm/lib/Target/AArch64/AArch64ISelLowering.h2
-rw-r--r--llvm/lib/Target/PowerPC/PPCISelLowering.cpp6
-rw-r--r--llvm/lib/Target/PowerPC/PPCISelLowering.h2
-rw-r--r--llvm/lib/Target/X86/X86ISelLowering.cpp4
-rw-r--r--llvm/lib/Target/X86/X86ISelLowering.h2
8 files changed, 26 insertions, 18 deletions
diff --git a/llvm/include/llvm/Target/TargetLowering.h b/llvm/include/llvm/Target/TargetLowering.h
index d9d9f6fa1d6..bd23b748a0a 100644
--- a/llvm/include/llvm/Target/TargetLowering.h
+++ b/llvm/include/llvm/Target/TargetLowering.h
@@ -2732,10 +2732,12 @@ public:
return SDValue();
}
- /// Indicate whether this target prefers to combine the given number of FDIVs
- /// with the same divisor.
- virtual bool combineRepeatedFPDivisors(unsigned NumUsers) const {
- return false;
+ /// Indicate whether this target prefers to combine FDIVs with the same
+ /// divisor. If the transform should never be done, return zero. If the
+ /// transform should be done, return the minimum number of divisor uses
+ /// that must exist.
+ virtual unsigned combineRepeatedFPDivisors() const {
+ return 0;
}
/// Hooks for building estimates in place of slower divisions and square
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index b06d53310bb..de2651650ef 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -8247,23 +8247,29 @@ SDValue DAGCombiner::combineRepeatedFPDivisors(SDNode *N) {
if (!DAG.getTarget().Options.UnsafeFPMath)
return SDValue();
+ // Skip if current node is a reciprocal.
SDValue N0 = N->getOperand(0);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
-
- // Skip if current node is a reciprocal.
if (N0CFP && N0CFP->isExactlyValue(1.0))
return SDValue();
+ // Exit early if the target does not want this transform or if there can't
+ // possibly be enough uses of the divisor to make the transform worthwhile.
SDValue N1 = N->getOperand(1);
- SmallVector<SDNode *, 4> Users;
+ unsigned MinUses = TLI.combineRepeatedFPDivisors();
+ if (!MinUses || N1->use_size() < MinUses)
+ return SDValue();
// Find all FDIV users of the same divisor.
+ SmallVector<SDNode *, 4> Users;
for (auto *U : N1->uses()) {
if (U->getOpcode() == ISD::FDIV && U->getOperand(1) == N1)
Users.push_back(U);
}
- if (!TLI.combineRepeatedFPDivisors(Users.size()))
+ // Now that we have the actual number of divisor uses, make sure it meets
+ // the minimum threshold specified by the target.
+ if (Users.size() < MinUses)
return SDValue();
EVT VT = N->getValueType(0);
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index be8696b25a9..8a125f3c3f2 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -9427,10 +9427,10 @@ bool AArch64TargetLowering::useLoadStackGuardNode() const {
return true;
}
-bool AArch64TargetLowering::combineRepeatedFPDivisors(unsigned NumUsers) const {
+unsigned AArch64TargetLowering::combineRepeatedFPDivisors() const {
// Combine multiple FDIVs with the same divisor into multiple FMULs by the
// reciprocal if there are three or more FDIVs.
- return NumUsers > 2;
+ return 3;
}
TargetLoweringBase::LegalizeTypeAction
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
index 92f38bef133..7820112ab2c 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -477,7 +477,7 @@ private:
SDValue BuildSDIVPow2(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
std::vector<SDNode *> *Created) const override;
- bool combineRepeatedFPDivisors(unsigned NumUsers) const override;
+ unsigned combineRepeatedFPDivisors() const override;
ConstraintType getConstraintType(StringRef Constraint) const override;
unsigned getRegisterByName(const char* RegName, EVT VT,
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index ea5a663a5a1..e7bc9030e98 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -9131,7 +9131,7 @@ SDValue PPCTargetLowering::getRecipEstimate(SDValue Operand,
return SDValue();
}
-bool PPCTargetLowering::combineRepeatedFPDivisors(unsigned NumUsers) const {
+unsigned PPCTargetLowering::combineRepeatedFPDivisors() const {
// Note: This functionality is used only when unsafe-fp-math is enabled, and
// on cores with reciprocal estimates (which are used when unsafe-fp-math is
// enabled for division), this functionality is redundant with the default
@@ -9144,12 +9144,12 @@ bool PPCTargetLowering::combineRepeatedFPDivisors(unsigned NumUsers) const {
// one FP pipeline) for three or more FDIVs (for generic OOO cores).
switch (Subtarget.getDarwinDirective()) {
default:
- return NumUsers > 2;
+ return 3;
case PPC::DIR_440:
case PPC::DIR_A2:
case PPC::DIR_E500mc:
case PPC::DIR_E5500:
- return NumUsers > 1;
+ return 2;
}
}
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 6e13533cfdb..cbd5add8488 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -853,7 +853,7 @@ namespace llvm {
bool &UseOneConstNR) const override;
SDValue getRecipEstimate(SDValue Operand, DAGCombinerInfo &DCI,
unsigned &RefinementSteps) const override;
- bool combineRepeatedFPDivisors(unsigned NumUsers) const override;
+ unsigned combineRepeatedFPDivisors() const override;
CCAssignFn *useFastISelCCs(unsigned Flag) const;
};
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index a99cc206451..de4506dd4d8 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -13308,8 +13308,8 @@ SDValue X86TargetLowering::getRecipEstimate(SDValue Op,
/// This is because we still need one division to calculate the reciprocal and
/// then we need two multiplies by that reciprocal as replacements for the
/// original divisions.
-bool X86TargetLowering::combineRepeatedFPDivisors(unsigned NumUsers) const {
- return NumUsers > 1;
+unsigned X86TargetLowering::combineRepeatedFPDivisors() const {
+ return 2;
}
static bool isAllOnes(SDValue V) {
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index 3d058e8da13..18f823c6201 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1124,7 +1124,7 @@ namespace llvm {
unsigned &RefinementSteps) const override;
/// Reassociate floating point divisions into multiply by reciprocal.
- bool combineRepeatedFPDivisors(unsigned NumUsers) const override;
+ unsigned combineRepeatedFPDivisors() const override;
};
namespace X86 {
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