[InstCombine] add tests for bitcasted selects; NFC

llvm-svn: 286978

llvm/test/Transforms/InstCombine/bitcast.ll

@@ -113,6 +113,90 @@ define <4 x i32> @bitcast_xor_bitcast(<4 x i32> %a, i128 %b) {
   ret <4 x i32> %bc2
 }
 
+; FIXME: Change the type of the vector select to eliminate 2 bitcasts.
+; https://llvm.org/bugs/show_bug.cgi?id=6137#c6
+
+define <4 x float> @bitcast_vector_select(<4 x float> %x, <2 x i64> %y, <4 x i1> %cmp) {
+; CHECK-LABEL: @bitcast_vector_select(
+; CHECK-NEXT:    [[T4:%.*]] = bitcast <4 x float> %x to <4 x i32>
+; CHECK-NEXT:    [[T5:%.*]] = bitcast <2 x i64> %y to <4 x i32>
+; CHECK-NEXT:    [[T6:%.*]] = select <4 x i1> %cmp, <4 x i32> [[T4]], <4 x i32> [[T5]]
+; CHECK-NEXT:    [[T7:%.*]] = bitcast <4 x i32> [[T6]] to <4 x float>
+; CHECK-NEXT:    ret <4 x float> [[T7]]
+;
+  %t4 = bitcast <4 x float> %x to <4 x i32>
+  %t5 = bitcast <2 x i64> %y to <4 x i32>
+  %t6 = select <4 x i1> %cmp, <4 x i32> %t4, <4 x i32> %t5
+  %t7 = bitcast <4 x i32> %t6 to <4 x float>
+  ret <4 x float> %t7
+}
+
+; FIXME: Change the type of the scalar select to eliminate a bitcast.
+
+define float @bitcast_scalar_select(float %x, <4 x i8> %y, i1 %cmp) {
+; CHECK-LABEL: @bitcast_scalar_select(
+; CHECK-NEXT:    [[T4:%.*]] = bitcast float %x to <4 x i8>
+; CHECK-NEXT:    [[T6:%.*]] = select i1 %cmp, <4 x i8> [[T4]], <4 x i8> %y
+; CHECK-NEXT:    [[T7:%.*]] = bitcast <4 x i8> [[T6]] to float
+; CHECK-NEXT:    ret float [[T7]]
+;
+  %t4 = bitcast float %x to <4 x i8>
+  %t6 = select i1 %cmp, <4 x i8> %t4, <4 x i8> %y
+  %t7 = bitcast <4 x i8> %t6 to float
+  ret float %t7
+}
+
+; FIXME: Change the type of the scalar select of vectors to eliminate 2 bitcasts.
+
+define <4 x float> @bitcast_scalar_select_of_vectors(<4 x float> %x, <2 x i64> %y, i1 %cmp) {
+; CHECK-LABEL: @bitcast_scalar_select_of_vectors(
+; CHECK-NEXT:    [[T4:%.*]] = bitcast <4 x float> %x to <4 x i32>
+; CHECK-NEXT:    [[T5:%.*]] = bitcast <2 x i64> %y to <4 x i32>
+; CHECK-NEXT:    [[T6:%.*]] = select i1 %cmp, <4 x i32> [[T4]], <4 x i32> [[T5]]
+; CHECK-NEXT:    [[T7:%.*]] = bitcast <4 x i32> [[T6]] to <4 x float>
+; CHECK-NEXT:    ret <4 x float> [[T7]]
+;
+  %t4 = bitcast <4 x float> %x to <4 x i32>
+  %t5 = bitcast <2 x i64> %y to <4 x i32>
+  %t6 = select i1 %cmp, <4 x i32> %t4, <4 x i32> %t5
+  %t7 = bitcast <4 x i32> %t6 to <4 x float>
+  ret <4 x float> %t7
+}
+
+; Can't change the type of the vector select if the dest type is scalar.
+
+define float @bitcast_vector_select_no_fold1(float %x, <2 x i16> %y, <4 x i1> %cmp) {
+; CHECK-LABEL: @bitcast_vector_select_no_fold1(
+; CHECK-NEXT:    [[T4:%.*]] = bitcast float %x to <4 x i8>
+; CHECK-NEXT:    [[T5:%.*]] = bitcast <2 x i16> %y to <4 x i8>
+; CHECK-NEXT:    [[T6:%.*]] = select <4 x i1> %cmp, <4 x i8> [[T4]], <4 x i8> [[T5]]
+; CHECK-NEXT:    [[T7:%.*]] = bitcast <4 x i8> [[T6]] to float
+; CHECK-NEXT:    ret float [[T7]]
+;
+  %t4 = bitcast float %x to <4 x i8>
+  %t5 = bitcast <2 x i16> %y to <4 x i8>
+  %t6 = select <4 x i1> %cmp, <4 x i8> %t4, <4 x i8> %t5
+  %t7 = bitcast <4 x i8> %t6 to float
+  ret float %t7
+}
+
+; Can't change the type of the vector select if the number of elements in the dest type is not the same.
+
+define <2 x float> @bitcast_vector_select_no_fold2(<2 x float> %x, <4 x i16> %y, <8 x i1> %cmp) {
+; CHECK-LABEL: @bitcast_vector_select_no_fold2(
+; CHECK-NEXT:    [[T4:%.*]] = bitcast <2 x float> %x to <8 x i8>
+; CHECK-NEXT:    [[T5:%.*]] = bitcast <4 x i16> %y to <8 x i8>
+; CHECK-NEXT:    [[T6:%.*]] = select <8 x i1> %cmp, <8 x i8> [[T4]], <8 x i8> [[T5]]
+; CHECK-NEXT:    [[T7:%.*]] = bitcast <8 x i8> [[T6]] to <2 x float>
+; CHECK-NEXT:    ret <2 x float> [[T7]]
+;
+  %t4 = bitcast <2 x float> %x to <8 x i8>
+  %t5 = bitcast <4 x i16> %y to <8 x i8>
+  %t6 = select <8 x i1> %cmp, <8 x i8> %t4, <8 x i8> %t5
+  %t7 = bitcast <8 x i8> %t6 to <2 x float>
+  ret <2 x float> %t7
+}
+
 ; Optimize bitcasts that are extracting low element of vector.  This happens because of SRoA.
 ; rdar://7892780
 define float @test2(<2 x float> %A, <2 x i32> %B) {