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-rw-r--r--llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp83
1 files changed, 0 insertions, 83 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index f25ce87..6118933 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -4846,94 +4846,11 @@ AMDGPUTargetLowering::foldFreeOpFromSelect(TargetLowering::DAGCombinerInfo &DCI,
return SDValue();
}
-// Detect when CMP and SELECT use the same constant and fold them to avoid
-// loading the constant twice. Specifically handles patterns like:
-// %cmp = icmp eq i32 %val, 4242
-// %sel = select i1 %cmp, i32 4242, i32 %other
-// It can be optimized to reuse %val instead of 4242 in select.
-static SDValue
-foldCmpSelectWithSharedConstant(SDNode *N, TargetLowering::DAGCombinerInfo &DCI,
- const AMDGPUSubtarget *ST) {
- SDValue Cond = N->getOperand(0);
- SDValue TrueVal = N->getOperand(1);
- SDValue FalseVal = N->getOperand(2);
-
- // Check if condition is a comparison.
- if (Cond.getOpcode() != ISD::SETCC)
- return SDValue();
-
- SDValue LHS = Cond.getOperand(0);
- SDValue RHS = Cond.getOperand(1);
- ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get();
-
- bool isFloatingPoint = LHS.getValueType().isFloatingPoint();
- bool isInteger = LHS.getValueType().isInteger();
-
- // Handle simple floating-point and integer types only.
- if (!isFloatingPoint && !isInteger)
- return SDValue();
-
- bool isEquality = CC == (isFloatingPoint ? ISD::SETOEQ : ISD::SETEQ);
- bool isNonEquality = CC == (isFloatingPoint ? ISD::SETONE : ISD::SETNE);
- if (!isEquality && !isNonEquality)
- return SDValue();
-
- SDValue ArgVal, ConstVal;
- if ((isFloatingPoint && isa<ConstantFPSDNode>(RHS)) ||
- (isInteger && isa<ConstantSDNode>(RHS))) {
- ConstVal = RHS;
- ArgVal = LHS;
- } else if ((isFloatingPoint && isa<ConstantFPSDNode>(LHS)) ||
- (isInteger && isa<ConstantSDNode>(LHS))) {
- ConstVal = LHS;
- ArgVal = RHS;
- } else {
- return SDValue();
- }
-
- // Check if constant should not be optimized - early return if not.
- if (isFloatingPoint) {
- const APFloat &Val = cast<ConstantFPSDNode>(ConstVal)->getValueAPF();
- const GCNSubtarget *GCNST = static_cast<const GCNSubtarget *>(ST);
-
- // Only optimize normal floating-point values (finite, non-zero, and
- // non-subnormal as per IEEE 754), skip optimization for inlinable
- // floating-point constants.
- if (!Val.isNormal() || GCNST->getInstrInfo()->isInlineConstant(Val))
- return SDValue();
- } else {
- int64_t IntVal = cast<ConstantSDNode>(ConstVal)->getSExtValue();
-
- // Skip optimization for inlinable integer immediates.
- // Inlinable immediates include: -16 to 64 (inclusive).
- if (IntVal >= -16 && IntVal <= 64)
- return SDValue();
- }
-
- // For equality and non-equality comparisons, patterns:
- // select (setcc x, const), const, y -> select (setcc x, const), x, y
- // select (setccinv x, const), y, const -> select (setccinv x, const), y, x
- if (!(isEquality && TrueVal == ConstVal) &&
- !(isNonEquality && FalseVal == ConstVal))
- return SDValue();
-
- SDValue SelectLHS = (isEquality && TrueVal == ConstVal) ? ArgVal : TrueVal;
- SDValue SelectRHS =
- (isNonEquality && FalseVal == ConstVal) ? ArgVal : FalseVal;
- return DCI.DAG.getNode(ISD::SELECT, SDLoc(N), N->getValueType(0), Cond,
- SelectLHS, SelectRHS);
-}
-
SDValue AMDGPUTargetLowering::performSelectCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
if (SDValue Folded = foldFreeOpFromSelect(DCI, SDValue(N, 0)))
return Folded;
- // Try to fold CMP + SELECT patterns with shared constants (both FP and
- // integer).
- if (SDValue Folded = foldCmpSelectWithSharedConstant(N, DCI, Subtarget))
- return Folded;
-
SDValue Cond = N->getOperand(0);
if (Cond.getOpcode() != ISD::SETCC)
return SDValue();