[InstCombine] add tests for disguised vector trunc; NFC
diff --git a/llvm/test/Transforms/InstCombine/shuffle-cast.ll b/llvm/test/Transforms/InstCombine/shuffle-cast.ll
new file mode 100644
index 0000000..e4b21ff
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/shuffle-cast.ll
@@ -0,0 +1,56 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S -data-layout="e" | FileCheck %s --check-prefixes=ANY,LE
+; RUN: opt < %s -instcombine -S -data-layout="E" | FileCheck %s --check-prefixes=ANY,BE
+
+define <4 x i16> @trunc_little_endian(<4 x i32> %x) {
+; ANY-LABEL: @trunc_little_endian(
+; ANY-NEXT: [[B:%.*]] = bitcast <4 x i32> [[X:%.*]] to <8 x i16>
+; ANY-NEXT: [[R:%.*]] = shufflevector <8 x i16> [[B]], <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+; ANY-NEXT: ret <4 x i16> [[R]]
+;
+ %b = bitcast <4 x i32> %x to <8 x i16>
+ %r = shufflevector <8 x i16> %b, <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+ ret <4 x i16> %r
+}
+
+define <4 x i16> @trunc_big_endian(<4 x i32> %x) {
+; ANY-LABEL: @trunc_big_endian(
+; ANY-NEXT: [[B:%.*]] = bitcast <4 x i32> [[X:%.*]] to <8 x i16>
+; ANY-NEXT: [[R:%.*]] = shufflevector <8 x i16> [[B]], <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+; ANY-NEXT: ret <4 x i16> [[R]]
+;
+ %b = bitcast <4 x i32> %x to <8 x i16>
+ %r = shufflevector <8 x i16> %b, <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+ ret <4 x i16> %r
+}
+
+declare void @use_v8i16(<8 x i16>)
+
+define <2 x i16> @trunc_little_endian_extra_use(<2 x i64> %x) {
+; ANY-LABEL: @trunc_little_endian_extra_use(
+; ANY-NEXT: [[B:%.*]] = bitcast <2 x i64> [[X:%.*]] to <8 x i16>
+; ANY-NEXT: call void @use_v8i16(<8 x i16> [[B]])
+; ANY-NEXT: [[R:%.*]] = shufflevector <8 x i16> [[B]], <8 x i16> undef, <2 x i32> <i32 0, i32 4>
+; ANY-NEXT: ret <2 x i16> [[R]]
+;
+ %b = bitcast <2 x i64> %x to <8 x i16>
+ call void @use_v8i16(<8 x i16> %b)
+ %r = shufflevector <8 x i16> %b, <8 x i16> undef, <2 x i32> <i32 0, i32 4>
+ ret <2 x i16> %r
+}
+
+declare void @use_v12i11(<12 x i11>)
+
+define <4 x i11> @trunc_big_endian_extra_use(<4 x i33> %x) {
+; ANY-LABEL: @trunc_big_endian_extra_use(
+; ANY-NEXT: [[B:%.*]] = bitcast <4 x i33> [[X:%.*]] to <12 x i11>
+; ANY-NEXT: call void @use_v12i11(<12 x i11> [[B]])
+; ANY-NEXT: [[R:%.*]] = shufflevector <12 x i11> [[B]], <12 x i11> undef, <4 x i32> <i32 2, i32 5, i32 8, i32 11>
+; ANY-NEXT: ret <4 x i11> [[R]]
+;
+ %b = bitcast <4 x i33> %x to <12 x i11>
+ call void @use_v12i11(<12 x i11> %b)
+ %r = shufflevector <12 x i11> %b, <12 x i11> undef, <4 x i32> <i32 2, i32 5, i32 8, i32 11>
+ ret <4 x i11> %r
+}
+
