3 files changed, 13 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index bce188e399a..db9a1048876 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -18129,6 +18129,9 @@ SDValue DAGCombiner::foldSelectCCToShiftAnd(const SDLoc &DL, SDValue N0,
 SDValue DAGCombiner::convertSelectOfFPConstantsToLoadOffset(
     const SDLoc &DL, SDValue N0, SDValue N1, SDValue N2, SDValue N3,
     ISD::CondCode CC) {
+  if (!TLI.reduceSelectOfFPConstantLoads(N0.getValueType().isFloatingPoint()))
+    return SDValue();
+
   // If we are before legalize types, we want the other legalization to happen
   // first (for example, to avoid messing with soft float).
   auto *TV = dyn_cast<ConstantFPSDNode>(N2);
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c2e13e95ad5..c11598f2eb4 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -4767,6 +4767,14 @@ bool X86TargetLowering::shouldConvertConstantLoadToIntImm(const APInt &Imm,
   return true;
 }
 
+bool X86TargetLowering::reduceSelectOfFPConstantLoads(bool IsFPSetCC) const {
+  // If we are using XMM registers in the ABI and the condition of the select is
+  // a floating-point compare and we have blendv or conditional move, then it is
+  // cheaper to select instead of doing a cross-register move and creating a
+  // load that depends on the compare result.
+  return !IsFPSetCC || !Subtarget.isTarget64BitLP64() || !Subtarget.hasAVX();
+}
+
 bool X86TargetLowering::convertSelectOfConstantsToMath(EVT VT) const {
   // TODO: It might be a win to ease or lift this restriction, but the generic
   // folds in DAGCombiner conflict with vector folds for an AVX512 target.
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index d95241237ab..fe151d89dd2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1041,6 +1041,8 @@ namespace llvm {
     bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                            Type *Ty) const override;
 
+    bool reduceSelectOfFPConstantLoads(bool IsFPSetCC) const override;
+
     bool convertSelectOfConstantsToMath(EVT VT) const override;
 
     bool decomposeMulByConstant(EVT VT, SDValue C) const override;