[PATCH] D90901: [DAGCombiner] Don't fold ((fma (fneg X), Y, (fneg Z)) to fneg (fma X, Y, Z))

[Jim Lin via Phabricator via llvm-commits]

Jim updated this revision to Diff 303364.
Jim added a comment.
Herald added a subscriber: nemanjai.

Update testcase.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D90901/new/

https://reviews.llvm.org/D90901

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/test/CodeGen/PowerPC/fma-combine.ll


Index: llvm/test/CodeGen/PowerPC/fma-combine.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/fma-combine.ll
+++ llvm/test/CodeGen/PowerPC/fma-combine.ll
@@ -171,16 +171,18 @@
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    addis 3, 2, .LCPI4_0 at toc@ha
 ; CHECK-NEXT:    addis 4, 2, .LCPI4_1 at toc@ha
-; CHECK-NEXT:    lfs 0, .LCPI4_0 at toc@l(3)
+; CHECK-NEXT:    addi 3, 3, .LCPI4_0 at toc@l
+; CHECK-NEXT:    lfsx 0, 0, 3
 ; CHECK-NEXT:    lfsx 2, 0, 3
 ; CHECK-NEXT:    addis 3, 2, .LCPI4_2 at toc@ha
 ; CHECK-NEXT:    lfs 3, .LCPI4_1 at toc@l(4)
-; CHECK-NEXT:    lfs 1, .LCPI4_2 at toc@l(3)
-; CHECK-NEXT:    fmr 4, 3
-; CHECK-NEXT:    xsmaddasp 3, 2, 0
-; CHECK-NEXT:    xsnmaddasp 4, 2, 0
-; CHECK-NEXT:    xsmaddasp 1, 2, 3
-; CHECK-NEXT:    xsmaddasp 1, 4, 2
+; CHECK-NEXT:    addis 4, 2, .LCPI4_3 at toc@ha
+; CHECK-NEXT:    lfs 4, .LCPI4_2 at toc@l(3)
+; CHECK-NEXT:    lfs 1, .LCPI4_3 at toc@l(4)
+; CHECK-NEXT:    xsmaddasp 3, 0, 2
+; CHECK-NEXT:    xsnmsubasp 4, 0, 2
+; CHECK-NEXT:    xsmaddasp 1, 0, 3
+; CHECK-NEXT:    xsmaddasp 1, 4, 0
 ; CHECK-NEXT:    blr
   %tmp = load float, float* undef, align 4
   %tmp2 = load float, float* undef, align 4
@@ -205,9 +207,9 @@
 ; CHECK-FAST-NEXT:    addis 4, 2, .LCPI5_0 at toc@ha
 ; CHECK-FAST-NEXT:    lfs 3, .LCPI5_1 at toc@l(3)
 ; CHECK-FAST-NEXT:    lfs 4, .LCPI5_0 at toc@l(4)
-; CHECK-FAST-NEXT:    xssubdp 0, 1, 3
+; CHECK-FAST-NEXT:    xsadddp 0, 1, 3
 ; CHECK-FAST-NEXT:    xsmaddadp 3, 1, 4
-; CHECK-FAST-NEXT:    xsmaddadp 0, 3, 2
+; CHECK-FAST-NEXT:    xsnmsubadp 0, 3, 2
 ; CHECK-FAST-NEXT:    fmr 1, 0
 ; CHECK-FAST-NEXT:    blr
 ;
@@ -218,8 +220,8 @@
 ; CHECK-FAST-NOVSX-NEXT:    lfs 0, .LCPI5_0 at toc@l(3)
 ; CHECK-FAST-NOVSX-NEXT:    lfs 3, .LCPI5_1 at toc@l(4)
 ; CHECK-FAST-NOVSX-NEXT:    fmadd 3, 1, 3, 0
-; CHECK-FAST-NOVSX-NEXT:    fsub 0, 1, 0
-; CHECK-FAST-NOVSX-NEXT:    fmadd 1, 3, 2, 0
+; CHECK-FAST-NOVSX-NEXT:    fadd 0, 1, 0
+; CHECK-FAST-NOVSX-NEXT:    fnmsub 1, 3, 2, 0
 ; CHECK-FAST-NOVSX-NEXT:    blr
 ;
 ; CHECK-LABEL: getNegatedExpression_crash:
@@ -228,9 +230,9 @@
 ; CHECK-NEXT:    addis 4, 2, .LCPI5_0 at toc@ha
 ; CHECK-NEXT:    lfs 3, .LCPI5_1 at toc@l(3)
 ; CHECK-NEXT:    lfs 4, .LCPI5_0 at toc@l(4)
-; CHECK-NEXT:    xssubdp 0, 1, 3
+; CHECK-NEXT:    xsadddp 0, 1, 3
 ; CHECK-NEXT:    xsmaddadp 3, 1, 4
-; CHECK-NEXT:    xsmaddadp 0, 3, 2
+; CHECK-NEXT:    xsnmsubadp 0, 3, 2
 ; CHECK-NEXT:    fmr 1, 0
 ; CHECK-NEXT:    blr
   %neg = fneg reassoc double %x
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -13374,12 +13374,6 @@
     }
   }
 
-  // fold ((fma (fneg X), Y, (fneg Z)) -> fneg (fma X, Y, Z))
-  // fold ((fma X, (fneg Y), (fneg Z)) -> fneg (fma X, Y, Z))
-  if (!TLI.isFNegFree(VT))
-    if (SDValue Neg = TLI.getCheaperNegatedExpression(
-            SDValue(N, 0), DAG, LegalOperations, ForCodeSize))
-      return DAG.getNode(ISD::FNEG, DL, VT, Neg);
   return SDValue();
 }
 


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