[AArch64] Add arithmetic zext bswap tests.

As requested on D58017.

llvm-svn: 354872

llvm/test/CodeGen/AArch64/arm64-rev.ll

@@ -61,6 +61,22 @@ entry:
   ret i32 %3
 }
 
+define i32 @test_rev_w_srl16_add(i8 %a, i8 %b) {
+; CHECK-LABEL: test_rev_w_srl16_add:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    and w8, w0, #0xff
+; CHECK-NEXT:    add w8, w8, w1, uxtb
+; CHECK-NEXT:    rev16 w0, w8
+; CHECK-NEXT:    ret
+entry:
+  %0 = zext i8 %a to i32
+  %1 = zext i8 %b to i32
+  %2 = add i32 %0, %1
+  %3 = tail call i32 @llvm.bswap.i32(i32 %2)
+  %4 = lshr i32 %3, 16
+  ret i32 %4
+}
+
 ; Canonicalize (srl (bswap x), 32) to (rotr (bswap x), 32) if the high 32-bits
 ; of %a are zero. This optimizes rev + lsr 32 to rev32.
 define i64 @test_rev_x_srl32(i32 %a) {
@@ -90,6 +106,20 @@ entry:
   ret i64 %3
 }
 
+define i64 @test_rev_x_srl32_shift(i64 %a) {
+; CHECK-LABEL: test_rev_x_srl32_shift:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    ubfx x8, x0, #2, #29
+; CHECK-NEXT:    rev32 x0, x8
+; CHECK-NEXT:    ret
+entry:
+  %0 = shl i64 %a, 33
+  %1 = lshr i64 %0, 35
+  %2 = tail call i64 @llvm.bswap.i64(i64 %1)
+  %3 = lshr i64 %2, 32
+  ret i64 %3
+}
+
 declare i32 @llvm.bswap.i32(i32) nounwind readnone
 declare i64 @llvm.bswap.i64(i64) nounwind readnone