[X86][SSE] Relax use limits for lowerAddSubToHorizontalOp (PR32433)

Now that we can use HADD/SUB for scalar additions from any pair of extracted elements (D61263), we can relax the one use limit as we will be able to merge multiple uses into using the same HADD/SUB op.

This exposes a couple of missed opportunities in LowerBuildVectorv4x32 which will be committed separately.

Differential Revision: https://reviews.llvm.org/D61782

llvm-svn: 360594

1 files changed, 2 insertions, 7 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 58815524b0a..d4c2b108537 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -19033,16 +19033,11 @@ static SDValue lowerAddSubToHorizontalOp(SDValue Op, SelectionDAG &DAG,
   if (!IsFP && !Subtarget.hasSSSE3())
     return Op;
 
-  // Defer forming the minimal horizontal op if the vector source has more than
-  // the 2 extract element uses that we're matching here. In that case, we might
-  // form a horizontal op that includes more than 1 add/sub op.
+  // Extract from a common vector.
   if (LHS.getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
       RHS.getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
       LHS.getOperand(0) != RHS.getOperand(0) ||
-      !LHS.getOperand(0)->hasNUsesOfValue(2, 0))
-    return Op;
-
-  if (!isa<ConstantSDNode>(LHS.getOperand(1)) ||
+      !isa<ConstantSDNode>(LHS.getOperand(1)) ||
       !isa<ConstantSDNode>(RHS.getOperand(1)) ||
       !shouldUseHorizontalOp(true, DAG, Subtarget))
     return Op;