[InstSimplify] Add tests to show missed bitcast folding opportunities.

InstSimplify doesn't always know how to fold a bitcast of a constant vector.
In particular, the logic in InstSimplify doesn't know how to handle the case
where the constant vector in input contains some undef elements, and the
number of elements is smaller than the number of elements of the bitcast
vector type.

llvm-svn: 281332

diff --git a/llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll b/llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll
index 6878343..126aba6 100644 (file)
--- a/llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll
+++ b/llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll
@@ -123,3 +123,147 @@ define <2 x double> @foo6() {
   %cast = bitcast <4 x i32><i32 -1, i32 -1, i32 -1, i32 -1> to <2 x double>
   ret <2 x double> %cast
 }
+
+define <4 x i32> @bitcast_constexpr_4i32_2i64_u2() {
+; CHECK-LABEL: @bitcast_constexpr_4i32_2i64_u2(
+; CHECK-NEXT:    ret <4 x i32> bitcast (<2 x i64> <i64 undef, i64 2> to <4 x i32>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 2> to <4 x i32>
+  ret <4 x i32> %cast
+}
+
+define <4 x i32> @bitcast_constexpr_4i32_2i64_1u() {
+; CHECK-LABEL: @bitcast_constexpr_4i32_2i64_1u(
+; CHECK-NEXT:    ret <4 x i32> bitcast (<2 x i64> <i64 1, i64 undef> to <4 x i32>)
+;
+  %cast = bitcast <2 x i64><i64 1, i64 undef> to <4 x i32>
+  ret <4 x i32> %cast
+}
+
+define <4 x i32> @bitcast_constexpr_4i32_2i64() {
+; CHECK-LABEL: @bitcast_constexpr_4i32_2i64(
+; CHECK-NEXT:    ret <4 x i32> bitcast (<2 x i64> <i64 undef, i64 2> to <4 x i32>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 2> to <4 x i32>
+  ret <4 x i32> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_2i64_u2() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_2i64_u2(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<2 x i64> <i64 undef, i64 2> to <8 x i16>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 2> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_2i64_1u() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_2i64_1u(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<2 x i64> <i64 1, i64 undef> to <8 x i16>)
+;
+  %cast = bitcast <2 x i64><i64 1, i64 undef> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_2i64_u65536() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_2i64_u65536(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<2 x i64> <i64 undef, i64 65536> to <8 x i16>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 65536> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_2i64_u2() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_2i64_u2(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<2 x i64> <i64 undef, i64 2> to <16 x i8>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 2> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_2i64_256u() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_2i64_256u(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<2 x i64> <i64 256, i64 undef> to <16 x i8>)
+;
+  %cast = bitcast <2 x i64><i64 256, i64 undef> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_2i64_u256() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_2i64_u256(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<2 x i64> <i64 undef, i64 256> to <16 x i8>)
+;
+  %cast = bitcast <2 x i64><i64 undef, i64 256> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_4i32_uu22() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_4i32_uu22(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<4 x i32> <i32 undef, i32 undef, i32 2, i32 2> to <8 x i16>)
+;
+  %cast = bitcast <4 x i32><i32 undef, i32 undef, i32 2, i32 2> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_4i32_10uu() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_4i32_10uu(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<4 x i32> <i32 1, i32 0, i32 undef, i32 undef> to <8 x i16>)
+;
+  %cast = bitcast <4 x i32><i32 1, i32 0, i32 undef, i32 undef> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <8 x i16> @bitcast_constexpr_8i16_4i32_u257u256() {
+; CHECK-LABEL: @bitcast_constexpr_8i16_4i32_u257u256(
+; CHECK-NEXT:    ret <8 x i16> bitcast (<4 x i32> <i32 undef, i32 65536, i32 undef, i32 65536> to <8 x i16>)
+;
+  %cast = bitcast <4 x i32><i32 undef, i32 65536, i32 undef, i32 65536> to <8 x i16>
+  ret <8 x i16> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_4i32_u2u2() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_4i32_u2u2(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<4 x i32> <i32 undef, i32 2, i32 undef, i32 2> to <16 x i8>)
+;
+  %cast = bitcast <4 x i32><i32 undef, i32 2, i32 undef, i32 2> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_4i32_1u1u() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_4i32_1u1u(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<4 x i32> <i32 1, i32 undef, i32 1, i32 undef> to <16 x i8>)
+;
+  %cast = bitcast <4 x i32><i32 1, i32 undef, i32 1, i32 undef> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_4i32_u256uu() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_4i32_u256uu(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<4 x i32> <i32 undef, i32 256, i32 undef, i32 undef> to <16 x i8>)
+;
+  %cast = bitcast <4 x i32><i32 undef, i32 256, i32 undef, i32 undef> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_8i16_u2u2u2u2() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_8i16_u2u2u2u2(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<8 x i16> <i16 undef, i16 2, i16 undef, i16 2, i16 undef, i16 2, i16 undef, i16 2> to <16 x i8>)
+;
+  %cast = bitcast <8 x i16><i16 undef, i16 2, i16 undef, i16 2, i16 undef, i16 2, i16 undef, i16 2> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_8i16_1u1u1u1u() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_8i16_1u1u1u1u(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<8 x i16> <i16 1, i16 undef, i16 1, i16 undef, i16 1, i16 undef, i16 1, i16 undef> to <16 x i8>)
+;
+  %cast = bitcast <8 x i16><i16 1, i16 undef, i16 1, i16 undef, i16 1, i16 undef, i16 1, i16 undef> to <16 x i8>
+  ret <16 x i8> %cast
+}
+
+define <16 x i8> @bitcast_constexpr_16i8_8i16_u256uuu256uu() {
+; CHECK-LABEL: @bitcast_constexpr_16i8_8i16_u256uuu256uu(
+; CHECK-NEXT:    ret <16 x i8> bitcast (<8 x i16> <i16 undef, i16 256, i16 undef, i16 undef, i16 undef, i16 256, i16 undef, i16 undef> to <16 x i8>)
+;
+  %cast = bitcast <8 x i16><i16 undef, i16 256, i16 undef, i16 undef, i16 undef, i16 256, i16 undef, i16 undef> to <16 x i8>
+  ret <16 x i8> %cast
+}