diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 3446ee0efc450d..749a5e83058e7b 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -5773,8 +5773,10 @@ 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()) + if (!Op.hasOneUse() && CFP.use_empty()) { + RemoveDeadNode(CFP); break; + } Cost = NegatibleCost::Neutral; return CFP; } diff --git a/llvm/test/CodeGen/X86/pr47517.ll b/llvm/test/CodeGen/X86/pr47517.ll new file mode 100644 index 00000000000000..6b508acf15dda2 --- /dev/null +++ b/llvm/test/CodeGen/X86/pr47517.ll @@ -0,0 +1,28 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc -mtriple x86_64 < %s | FileCheck %s + +; To ensure unused floating point constant is removed in negation +define float @test(float %src, float* %p) { +; CHECK-LABEL: test: +; CHECK: # %bb.0: # %entry +; CHECK-NEXT: movq $0, (%rdi) +; CHECK-NEXT: xorps %xmm0, %xmm0 +; CHECK-NEXT: retq +entry: + %a0 = getelementptr inbounds float, float* %p, i32 0 + %a1 = getelementptr inbounds float, float* %p, i32 1 + store float 0.000000e+00, float* %a0 + store float 0.000000e+00, float* %a1 + %zero = load float, float* %a0 + %fmul1 = fmul fast float %zero, %src + %fadd1 = fadd fast float %fmul1, %zero + %fmul2 = fmul fast float %fadd1, 2.000000e+00 + %fmul3 = fmul fast float %fmul2, %fmul2 + %fmul4 = fmul fast float %fmul2, 2.000000e+00 + %fadd2 = fadd fast float %fmul4, -3.000000e+00 + %fmul5 = fmul fast float %fadd2, %fmul2 + %fadd3 = fadd fast float %fmul2, %src + %fadd4 = fadd fast float %fadd3, %fmul5 + %fmul6 = fmul fast float %fmul3, %fadd4 + ret float %fmul6 +}