[InstCombine] add more tests for shuffle folding; NFC

As discussed in D62024, we want to limit any potential IR
transforms of shuffles to cases where we know the SDAG
conversion would result in equivalent patterns for these
IR variants.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361317 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/Transforms/InstCombine/vec_shuffle.ll b/test/Transforms/InstCombine/vec_shuffle.ll
index 0d8296086b7e20ab054e895a90d6ebb0e29cffe4..821c0829076ba18a85a0905623968642469620cd 100644 (file)
--- a/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/test/Transforms/InstCombine/vec_shuffle.ll
@@ -1153,6 +1153,19 @@ define <7 x i8> @insert_subvector_shuffles(<3 x i8> %x, <3 x i8> %y) {
   ret <7 x i8> %s3
 }
 
+define <8 x i8> @insert_subvector_shuffles_pow2elts(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @insert_subvector_shuffles_pow2elts(
+; CHECK-NEXT:    [[S1:%.*]] = shufflevector <2 x i8> [[X:%.*]], <2 x i8> undef, <8 x i32> <i32 0, i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT:    [[S2:%.*]] = shufflevector <2 x i8> [[Y:%.*]], <2 x i8> undef, <8 x i32> <i32 0, i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT:    [[S3:%.*]] = shufflevector <8 x i8> [[S1]], <8 x i8> [[S2]], <8 x i32> <i32 0, i32 8, i32 1, i32 undef, i32 8, i32 1, i32 9, i32 0>
+; CHECK-NEXT:    ret <8 x i8> [[S3]]
+;
+  %s1 = shufflevector <2 x i8> %x, <2 x i8> undef, <8 x i32> <i32 0, i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+  %s2 = shufflevector <2 x i8> %y, <2 x i8> undef, <8 x i32> <i32 0, i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+  %s3 = shufflevector <8 x i8> %s1, <8 x i8> %s2, <8 x i32> <i32 0, i32 8, i32 1, i32 undef, i32 8, i32 1, i32 9, i32 0>
+  ret <8 x i8> %s3
+}
+
 ; The last shuffle may change the vector type.
 
 define <2 x i8> @insert_subvector_shuffles_narrowing(<3 x i8> %x, <3 x i8> %y) {
@@ -1168,6 +1181,19 @@ define <2 x i8> @insert_subvector_shuffles_narrowing(<3 x i8> %x, <3 x i8> %y) {
   ret <2 x i8> %s3
 }
 
+define <2 x i8> @insert_subvector_shuffles_narrowing_pow2elts(<4 x i8> %x, <4 x i8> %y) {
+; CHECK-LABEL: @insert_subvector_shuffles_narrowing_pow2elts(
+; CHECK-NEXT:    [[S1:%.*]] = shufflevector <4 x i8> [[X:%.*]], <4 x i8> undef, <8 x i32> <i32 0, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT:    [[S2:%.*]] = shufflevector <4 x i8> [[Y:%.*]], <4 x i8> undef, <8 x i32> <i32 0, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT:    [[S3:%.*]] = shufflevector <8 x i8> [[S1]], <8 x i8> [[S2]], <2 x i32> <i32 0, i32 8>
+; CHECK-NEXT:    ret <2 x i8> [[S3]]
+;
+  %s1 = shufflevector <4 x i8> %x, <4 x i8> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+  %s2 = shufflevector <4 x i8> %y, <4 x i8> undef, <8 x i32> <i32 0, i32 1, i32 undef, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
+  %s3 = shufflevector <8 x i8> %s1, <8 x i8> %s2, <2 x i32> <i32 0, i32 8>
+  ret <2 x i8> %s3
+}
+
 ; Similar to above, but this reduces to a widen with undefs of 'x'.
 
 define <4 x double> @insert_subvector_shuffles_identity(<2 x double> %x) {