Merge branch 'swift/main' of github.com:apple/llvm-project into swift/tensorflow-stage

* 'swift/main' of github.com:apple/llvm-project:
  [SelectionDAG] Don't remove unused negated constant immediately

Author: ainu-bot

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -5751,10 +5751,8 @@ SDValue TargetLowering::getNegatedExpression(SDValue Op, SelectionDAG &DAG,
 
     // If we already have the use of the negated floating constant, it is free
     // to negate it even it has multiple uses.
-    if (!Op.hasOneUse() && CFP.use_empty()) {
-      RemoveDeadNode(CFP);
+    if (!Op.hasOneUse() && CFP.use_empty())
       break;
-    }
     Cost = NegatibleCost::Neutral;
     return CFP;
   }

llvm/test/CodeGen/X86/pr47517.ll

@@ -26,3 +26,16 @@ entry:
   %fmul6 = fmul fast float %fmul3, %fadd4
   ret float %fmul6
 }
+
+; To ensure negated result will not be removed when NegX=NegY and
+; NegX is needed
+define float @test2(float %x, float %y) {
+  %add = fadd fast float %x, 750.0
+  %sub = fsub fast float %x, %add
+  %mul = fmul fast float %sub, %sub
+  %mul2 = fmul fast float %mul, %sub
+  %add2 = fadd fast float %mul2, 1.0
+  %add3 = fadd fast float %mul2, %add2
+  %mul3 = fmul fast float %y, %add3
+  ret float %mul3
+}