diff --git a/llvm/test/Transforms/VectorCombine/AMDGPU/shuffles-of-length-changing-shuffles.ll b/llvm/test/Transforms/VectorCombine/AMDGPU/shuffles-of-length-changing-shuffles.ll
new file mode 100644
index 0000000000000..e028b367a186c
--- /dev/null
+++ b/llvm/test/Transforms/VectorCombine/AMDGPU/shuffles-of-length-changing-shuffles.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -S -mtriple=amdgcn-- -mcpu=gfx1250 -passes=vector-combine < %s | FileCheck -check-prefix=OPT %s
+
+define <8 x i8> @extending0(<8 x i8> %a, <4 x i8> %b) {
+; OPT-LABEL: define <8 x i8> @extending0(
+; OPT-SAME: <8 x i8> [[A:%.*]], <4 x i8> [[B:%.*]]) #[[ATTR0:[0-9]+]] {
+; OPT-NEXT:    [[EXT0:%.*]] = shufflevector <4 x i8> [[B]], <4 x i8> [[B]], <8 x i32> <i32 poison, i32 poison, i32 3, i32 poison, i32 poison, i32 4, i32 poison, i32 poison>
+; OPT-NEXT:    [[EXT1:%.*]] = shufflevector <4 x i8> poison, <4 x i8> [[B]], <8 x i32> <i32 4, i32 poison, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
+; OPT-NEXT:    [[MERGE0:%.*]] = shufflevector <8 x i8> [[A]], <8 x i8> [[EXT0]], <8 x i32> <i32 10, i32 1, i32 2, i32 3, i32 13, i32 5, i32 6, i32 7>
+; OPT-NEXT:    [[MERGE1:%.*]] = shufflevector <8 x i8> [[EXT1]], <8 x i8> [[MERGE0]], <8 x i32> <i32 0, i32 8, i32 2, i32 9, i32 10, i32 11, i32 12, i32 13>
+; OPT-NEXT:    ret <8 x i8> [[MERGE1]]
+;
+  %ext0 =   shufflevector <4 x i8> %b, <4 x i8> %b,         <8 x i32> <i32 poison, i32 poison, i32 3, i32 poison, i32 poison, i32 4, i32 poison, i32 poison>
+  %ext1 =   shufflevector <4 x i8> poison, <4 x i8> %b,     <8 x i32> <i32 4, i32 poison, i32 7, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
+  %merge0 = shufflevector <8 x i8> %a, <8 x i8> %ext0,      <8 x i32> <i32 10, i32 1, i32 2, i32 3, i32 13, i32 5, i32 6, i32 7>
+  %merge1 = shufflevector <8 x i8> %ext1, <8 x i8> %merge0, <8 x i32> <i32 0, i32 8, i32 2, i32 9, i32 10, i32 11, i32 12, i32 13>
+  ret <8 x i8> %merge1
+}
+
+define <8 x i8> @extending_conflict(<8 x i8> %a, <4 x i8> %b) {
+; OPT-LABEL: define <8 x i8> @extending_conflict(
+; OPT-SAME: <8 x i8> [[A:%.*]], <4 x i8> [[B:%.*]]) #[[ATTR0]] {
+; OPT-NEXT:    [[EXT0:%.*]] = shufflevector <4 x i8> [[B]], <4 x i8> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
+; OPT-NEXT:    [[EXT1:%.*]] = shufflevector <4 x i8> [[B]], <4 x i8> poison, <8 x i32> <i32 0, i32 2, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
+; OPT-NEXT:    [[MERGE0:%.*]] = shufflevector <8 x i8> [[A]], <8 x i8> [[EXT0]], <8 x i32> <i32 10, i32 1, i32 2, i32 3, i32 15, i32 5, i32 6, i32 7>
+; OPT-NEXT:    [[MERGE1:%.*]] = shufflevector <8 x i8> [[EXT1]], <8 x i8> [[MERGE0]], <8 x i32> <i32 0, i32 8, i32 2, i32 9, i32 10, i32 11, i32 12, i32 13>
+; OPT-NEXT:    ret <8 x i8> [[MERGE1]]
+;
+  %ext0 =   shufflevector <4 x i8> %b, <4 x i8> poison,     <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
+  %ext1 =   shufflevector <4 x i8> %b, <4 x i8> poison,     <8 x i32> <i32 0, i32 2, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
+  %merge0 = shufflevector <8 x i8> %a, <8 x i8> %ext0,      <8 x i32> <i32 10, i32 1, i32 2, i32 3, i32 15, i32 5, i32 6, i32 7>
+  %merge1 = shufflevector <8 x i8> %ext1, <8 x i8> %merge0, <8 x i32> <i32 0, i32 8, i32 2, i32 9, i32 10, i32 11, i32 12, i32 13>
+  ret <8 x i8> %merge1
+}
+
+define <4 x i8> @shrinking0(<4 x i8> %a, <8 x i8> %b) {
+; OPT-LABEL: define <4 x i8> @shrinking0(
+; OPT-SAME: <4 x i8> [[A:%.*]], <8 x i8> [[B:%.*]]) #[[ATTR0]] {
+; OPT-NEXT:    [[SHRINK0:%.*]] = shufflevector <8 x i8> [[B]], <8 x i8> [[B]], <4 x i32> <i32 poison, i32 7, i32 8, i32 poison>
+; OPT-NEXT:    [[SHRINK1:%.*]] = shufflevector <8 x i8> poison, <8 x i8> [[B]], <4 x i32> <i32 poison, i32 poison, i32 8, i32 9>
+; OPT-NEXT:    [[MERGE0:%.*]] = shufflevector <4 x i8> [[A]], <4 x i8> [[SHRINK0]], <4 x i32> <i32 5, i32 6, i32 0, i32 1>
+; OPT-NEXT:    [[MERGE1:%.*]] = shufflevector <4 x i8> [[MERGE0]], <4 x i8> [[SHRINK1]], <4 x i32> <i32 0, i32 2, i32 6, i32 7>
+; OPT-NEXT:    ret <4 x i8> [[MERGE1]]
+;
+  %shrink0 = shufflevector <8 x i8> %b, <8 x i8> %b,            <4 x i32> <i32 poison, i32 7, i32 8, i32 poison>
+  %shrink1 = shufflevector <8 x i8> poison, <8 x i8> %b,        <4 x i32> <i32 poison, i32 poison, i32 8, i32 9>
+  %merge0  = shufflevector <4 x i8> %a, <4 x i8> %shrink0,      <4 x i32> <i32 5, i32 6, i32 0, i32 1>
+  %merge1  = shufflevector <4 x i8> %merge0, <4 x i8> %shrink1, <4 x i32> <i32 0, i32 2, i32 6, i32 7>
+  ret <4 x i8> %merge1
+}