[RISCV] Add test case showing failure to fold (fadd (reduce -0.0, X), Y) due to one...

If the -0.0 has multiple uses we won't fold the reduction.

diff --git a/llvm/test/CodeGen/RISCV/rvv/fold-binary-reduce.ll b/llvm/test/CodeGen/RISCV/rvv/fold-binary-reduce.ll
index ade4247..058263f 100644 (file)
--- a/llvm/test/CodeGen/RISCV/rvv/fold-binary-reduce.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fold-binary-reduce.ll
@@ -278,6 +278,28 @@ entry:
   ret float %res
 }
 
+define float @reduce_fadd4(float %x, float %y, <4 x float> %v, <4 x float> %w) {
+; CHECK-LABEL: reduce_fadd4:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetivli zero, 4, e32, m1, ta, ma
+; CHECK-NEXT:    vmv.s.x v10, zero
+; CHECK-NEXT:    vfredusum.vs v8, v8, v10
+; CHECK-NEXT:    vfmv.f.s fa5, v8
+; CHECK-NEXT:    vfredusum.vs v8, v9, v10
+; CHECK-NEXT:    vfmv.f.s fa4, v8
+; CHECK-NEXT:    fadd.s fa5, fa5, fa0
+; CHECK-NEXT:    fadd.s fa4, fa4, fa1
+; CHECK-NEXT:    fdiv.s fa0, fa5, fa4
+; CHECK-NEXT:    ret
+entry:
+  %rdx = call fast float @llvm.vector.reduce.fadd.v4f32(float -0.0, <4 x float> %v)
+  %rdx2 = call fast float @llvm.vector.reduce.fadd.v4f32(float -0.0, <4 x float> %w)
+  %res = fadd fast float %rdx, %x
+  %res2 = fadd fast float %rdx2, %y
+  %div = fdiv fast float %res, %res2
+  ret float %div
+}
+
 define float @reduce_fmax(float %x, <4 x float> %v) {
 ; CHECK-LABEL: reduce_fmax:
 ; CHECK:       # %bb.0: # %entry