[x86] add tests for PR40243; NFC

llvm-svn: 350646
diff --git a/llvm/test/CodeGen/X86/phaddsub-undef.ll b/llvm/test/CodeGen/X86/phaddsub-undef.ll
index 61f4ab4..a2212ed 100644
--- a/llvm/test/CodeGen/X86/phaddsub-undef.ll
+++ b/llvm/test/CodeGen/X86/phaddsub-undef.ll
@@ -93,6 +93,36 @@
   ret <8 x i32> %vecinit5
 }
 
+define <8 x i32> @PR40243_alt(<8 x i32> %a, <8 x i32> %b) {
+; SSE-LABEL: PR40243_alt:
+; SSE:       # %bb.0:
+; SSE-NEXT:    phaddd %xmm3, %xmm1
+; SSE-NEXT:    retq
+;
+; AVX1-LABEL: PR40243_alt:
+; AVX1:       # %bb.0:
+; AVX1-NEXT:    retq
+;
+; AVX2-LABEL: PR40243_alt:
+; AVX2:       # %bb.0:
+; AVX2-NEXT:    vphaddd %ymm0, %ymm0, %ymm0
+; AVX2-NEXT:    retq
+;
+; AVX512-LABEL: PR40243_alt:
+; AVX512:       # %bb.0:
+; AVX512-NEXT:    vphaddd %ymm0, %ymm0, %ymm0
+; AVX512-NEXT:    retq
+  %a4 = extractelement <8 x i32> %a, i32 4
+  %a5 = extractelement <8 x i32> %a, i32 5
+  %add4 = add i32 %a4, %a5
+  %b6 = extractelement <8 x i32> %b, i32 6
+  %b7 = extractelement <8 x i32> %b, i32 7
+  %add7 = add i32 %b6, %b7
+  %r4 = insertelement <8 x i32> undef, i32 %add4, i32 4
+  %r = insertelement <8 x i32> %r4, i32 %add7, i32 7
+  ret <8 x i32> %r
+}
+
 define <8 x i32> @test16_undef(<8 x i32> %a, <8 x i32> %b) {
 ; SSE-LABEL: test16_undef:
 ; SSE:       # %bb.0: