[PATCH] D28787: AMDGPU: Propagate fast math flags in fneg combines

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
Herald added a reviewer: tstellarAMD.
Herald added subscribers: tony-tye, yaxunl, nhaehnle, wdng, kzhuravl.

Can't for fma/mad since it seems they can't have flags currently.


https://reviews.llvm.org/D28787

Files:
  lib/Target/AMDGPU/AMDGPUISelLowering.cpp


Index: lib/Target/AMDGPU/AMDGPUISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -2933,7 +2933,7 @@
     else
       RHS = RHS.getOperand(0);
 
-    SDValue Res = DAG.getNode(ISD::FADD, SL, VT, LHS, RHS);
+    SDValue Res = DAG.getNode(ISD::FADD, SL, VT, LHS, RHS, N0->getFlags());
     if (!N0.hasOneUse())
       DAG.ReplaceAllUsesWith(N0, DAG.getNode(ISD::FNEG, SL, VT, Res));
     return Res;
@@ -2952,7 +2952,7 @@
     else
       RHS = DAG.getNode(ISD::FNEG, SL, VT, RHS);
 
-    SDValue Res = DAG.getNode(Opc, SL, VT, LHS, RHS);
+    SDValue Res = DAG.getNode(Opc, SL, VT, LHS, RHS, N0->getFlags());
     if (!N0.hasOneUse())
       DAG.ReplaceAllUsesWith(N0, DAG.getNode(ISD::FNEG, SL, VT, Res));
     return Res;
@@ -2976,7 +2976,7 @@
     else
       RHS = RHS.getOperand(0);
 
-    SDValue Res = DAG.getNode(Opc, SL, VT, LHS, MHS, RHS);
+    SDValue Res = DAG.getNode(Opc, SL, VT, LHS, MHS, RHS, N0->getFlags());
     if (!N0.hasOneUse())
       DAG.ReplaceAllUsesWith(N0, DAG.getNode(ISD::FNEG, SL, VT, Res));
     return Res;
@@ -3002,7 +3002,7 @@
     // (fneg (fp_extend x)) -> (fp_extend (fneg x))
     // (fneg (rcp x)) -> (rcp (fneg x))
     SDValue Neg = DAG.getNode(ISD::FNEG, SL, CvtSrc.getValueType(), CvtSrc);
-    return DAG.getNode(Opc, SL, VT, Neg);
+    return DAG.getNode(Opc, SL, VT, Neg, N0->getFlags());
   }
   case ISD::FP_ROUND: {
     SDValue CvtSrc = N0.getOperand(0);


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