Merge pull request #3617 from bjorn3/fix_small_popcnt

Fix popcnt for small integers

cranelift/codegen/src/isa/x64/lower.rs

@@ -2236,14 +2236,25 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
         Opcode::Popcnt => {
             let ty_tmp = ty.unwrap();
             if !ty_tmp.is_vector() {
-                let (ext_spec, ty) = match ctx.input_ty(insn, 0) {
-                    types::I8 | types::I16 => (Some(ExtSpec::ZeroExtendTo32), types::I32),
-                    a if a == types::I32 || a == types::I64 || a == types::I128 => (None, a),
-                    _ => unreachable!(),
-                };
+                let ty = ctx.input_ty(insn, 0);
 
                 if isa_flags.use_popcnt() {
                     match ty {
+                        types::I8 | types::I16 => {
+                            let src = RegMem::reg(extend_input_to_reg(
+                                ctx,
+                                inputs[0],
+                                ExtSpec::ZeroExtendTo32,
+                            ));
+                            let dst = get_output_reg(ctx, outputs[0]).only_reg().unwrap();
+                            ctx.emit(Inst::unary_rm_r(
+                                OperandSize::from_ty(types::I32),
+                                UnaryRmROpcode::Popcnt,
+                                src,
+                                dst,
+                            ));
+                            return Ok(());
+                        }
                         types::I32 | types::I64 => {
                             let src = input_to_reg_mem(ctx, inputs[0]);
                             let dst = get_output_reg(ctx, outputs[0]).only_reg().unwrap();
@@ -2299,6 +2310,12 @@ fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
                     }
                 }
 
+                let (ext_spec, ty) = match ty {
+                    types::I8 | types::I16 => (Some(ExtSpec::ZeroExtendTo32), types::I32),
+                    a if a == types::I32 || a == types::I64 || a == types::I128 => (None, a),
+                    _ => unreachable!(),
+                };
+
                 let (srcs, ty): (SmallVec<[RegMem; 2]>, Type) = if let Some(ext_spec) = ext_spec {
                     (
                         smallvec![RegMem::reg(extend_input_to_reg(ctx, inputs[0], ext_spec))],

cranelift/filetests/filetests/runtests/popcnt.clif

@@ -0,0 +1,100 @@
+test interpret
+test run
+target aarch64
+target x86_64
+target x86_64 has_popcnt=1
+
+function %popcnt_i8(i8) -> i8 {
+block0(v0: i8):
+    v1 = popcnt v0
+    return v1
+}
+; run: %popcnt_i8(1) == 1
+; run: %popcnt_i8(0x40) == 1
+; run: %popcnt_i8(-1) == 8
+; run: %popcnt_i8(0) == 0
+
+; Regression test for issue #3615
+function %inv_popcnt_i8(i8) -> i8 {
+block0(v0: i8):
+    v1 = bnot v0
+    v2 = popcnt v1
+    return v2
+}
+; run: %inv_popcnt_i8(1) == 7
+; run: %inv_popcnt_i8(0x40) == 7
+; run: %inv_popcnt_i8(-1) == 0
+; run: %inv_popcnt_i8(0) == 8
+
+function %popcnt_i16(i16) -> i16 {
+block0(v0: i16):
+    v1 = popcnt v0
+    return v1
+}
+; run: %popcnt_i16(1) == 1
+; run: %popcnt_i16(0x4000) == 1
+; run: %popcnt_i16(-1) == 16
+; run: %popcnt_i16(0) == 0
+
+; Regression test for issue #3615
+function %inv_popcnt_i16(i16) -> i16 {
+block0(v0: i16):
+    v1 = bnot v0
+    v2 = popcnt v1
+    return v2
+}
+; run: %inv_popcnt_i16(1) == 15
+; run: %inv_popcnt_i16(0x4000) == 15
+; run: %inv_popcnt_i16(-1) == 0
+; run: %inv_popcnt_i16(0) == 16
+
+function %popcnt_i32(i32) -> i32 {
+block0(v0: i32):
+    v1 = popcnt v0
+    return v1
+}
+; run: %popcnt_i32(1) == 1
+; run: %popcnt_i32(0x40000000) == 1
+; run: %popcnt_i32(-1) == 32
+; run: %popcnt_i32(0) == 0
+
+; Regression test for issue #3615
+function %inv_popcnt_i32(i32) -> i32 {
+block0(v0: i32):
+    v1 = bnot v0
+    v2 = popcnt v1
+    return v2
+}
+; run: %inv_popcnt_i32(1) == 31
+; run: %inv_popcnt_i32(0x40000000) == 31
+; run: %inv_popcnt_i32(-1) == 0
+; run: %inv_popcnt_i32(0) == 32
+
+function %popcnt_i64(i64) -> i64 {
+block0(v0: i64):
+    v1 = popcnt v0
+    return v1
+}
+; run: %popcnt_i64(1) == 1
+; run: %popcnt_i64(0x4000000000000000) == 1
+; run: %popcnt_i64(-1) == 64
+; run: %popcnt_i64(0) == 0
+
+; Regression test for issue #3615
+function %inv_popcnt_i64(i64) -> i64 {
+block0(v0: i64):
+    v1 = bnot v0
+    v2 = popcnt v1
+    return v2
+}
+; run: %inv_popcnt_i64(1) == 63
+; run: %inv_popcnt_i64(0x4000000000000000) == 63
+; run: %inv_popcnt_i64(-1) == 0
+; run: %inv_popcnt_i64(0) == 64
+
+function %popcnt_i8x16(i8x16) -> i8x16 {
+block0(v0: i8x16):
+    v1 = popcnt v0
+    return v1
+}
+; run: %popcnt_i8x16([1 1 1 1 0x40 0x40 0x40 0x40 0xff 0xff 0xff 0xff 0 0 0 0]) == [1 1 1 1 1 1 1 1 8 8 8 8 0 0 0 0]