[PATCH] D119793: [SelectionDAG] Add SPLAT_VECTOR to SelectionDAG::isConstantFPBuildVectorOrConstantFP.

[Craig Topper via Phabricator via llvm-commits]

craig.topper updated this revision to Diff 408982.
craig.topper added a comment.
Herald added subscribers: pcwang-thead, luismarques, apazos, sameer.abuasal, s.egerton, Jim, jocewei, PkmX, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, MaskRay, jrtc27, niosHD, sabuasal, simoncook, johnrusso, rbar, asb.

Add test case for simplifying fmul with 1.0.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119793/new/

https://reviews.llvm.org/D119793

Files:
  llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  llvm/test/CodeGen/RISCV/rvv/combine-splats.ll


Index: llvm/test/CodeGen/RISCV/rvv/combine-splats.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rvv/combine-splats.ll
+++ llvm/test/CodeGen/RISCV/rvv/combine-splats.ll
@@ -109,3 +109,25 @@
   %v2 = lshr <vscale x 8 x i16> %v1, %splat2
   ret <vscale x 8 x i16> %v2
 }
+
+; fold (fmul x, 1.0) -> x
+define <vscale x 2 x float> @combine_fmul_one(<vscale x 2 x float> %x) {
+; CHECK-LABEL: combine_fmul_one:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    ret
+  %ins = insertelement <vscale x 2 x float> poison, float 1.0, i32 0
+  %splat = shufflevector <vscale x 2 x float> %ins, <vscale x 2 x float> poison, <vscale x 2 x i32> zeroinitializer
+  %v = fmul <vscale x 2 x float> %x, %splat
+  ret <vscale x 2 x float> %v
+}
+
+; fold (fmul 1.0, x) -> x
+define <vscale x 2 x float> @combine_fmul_one_commuted(<vscale x 2 x float> %x) {
+; CHECK-LABEL: combine_fmul_one_commuted:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    ret
+  %ins = insertelement <vscale x 2 x float> poison, float 1.0, i32 0
+  %splat = shufflevector <vscale x 2 x float> %ins, <vscale x 2 x float> poison, <vscale x 2 x i32> zeroinitializer
+  %v = fmul <vscale x 2 x float> %splat, %x
+  ret <vscale x 2 x float> %v
+}
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -11107,6 +11107,10 @@
   if (ISD::isBuildVectorOfConstantFPSDNodes(N.getNode()))
     return N.getNode();
 
+  if ((N.getOpcode() == ISD::SPLAT_VECTOR) &&
+      isa<ConstantFPSDNode>(N.getOperand(0)))
+    return N.getNode();
+
   return nullptr;
 }
 


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