[WebAssembly] SIMD extract_lane

Implement instruction selection for all versions of the extract_lane
instruction. Use explicit sext/zext to differentiate between
extract_lane_s and extract_lane_u for applicable types, otherwise
default to extract_lane_u.

Reviewers: aheejin

Subscribers: sunfish, jgravelle-google, sbc100, llvm-commits

Differential Revision: https://reviews.llvm.org/D50597

Patch by Thomas Lively (tlively)

llvm-svn: 339707
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
index 5ff0ecb..1c0090e 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
@@ -12,19 +12,79 @@
 ///
 //===----------------------------------------------------------------------===//
 
-let Defs = [ARGUMENTS] in {
+// Immediate argument types
+def ImmByte : ImmLeaf<i32, [{ return 0 <= Imm && Imm < 256; }]>;
+foreach SIZE = [2, 4, 8, 16, 32] in
+def LaneIdx#SIZE : ImmLeaf<i32, "return 0 <= Imm && Imm < "#SIZE#";">;
 
+// lane extraction
+multiclass ExtractLane<ValueType vec_t, ImmLeaf imm_t,
+                       WebAssemblyRegClass reg_t, string name, bits<32> simdop,
+                       SDNode extract = vector_extract> {
+  defm "" : SIMD_I<(outs reg_t:$dst), (ins V128:$vec, I32:$idx),
+                   (outs), (ins I32:$idx),
+                   [(set reg_t:$dst,
+                     (extract (vec_t V128:$vec), (i32 imm_t:$idx)))],
+                   name#"\t$dst, $vec, $idx", name#"\t$idx", simdop>;
+}
+multiclass ExtractPat<ValueType lane_t, int mask> {
+  def _s : PatFrag<(ops node:$vec, node:$idx),
+                   (i32 (sext_inreg
+                     (i32 (vector_extract
+                       node:$vec,
+                       node:$idx
+                     )),
+                     lane_t
+                   ))>;
+  def _u : PatFrag<(ops node:$vec, node:$idx),
+                   (i32 (and
+                     (i32 (vector_extract
+                       node:$vec,
+                       node:$idx
+                     )),
+                     (i32 mask)
+                   ))>;
+}
+defm extract_i8x16 : ExtractPat<i8, 0xff>;
+defm extract_i16x8 : ExtractPat<i16, 0xffff>;
+multiclass ExtractLaneExtended<string sign, bits<32> baseInst> {
+  defm _I8x16 : ExtractLane<v16i8, LaneIdx16, I32, "i8x16.extract_lane"#sign,
+                            baseInst, !cast<PatFrag>("extract_i8x16"#sign)>;
+  defm _I16x8 : ExtractLane<v8i16, LaneIdx8, I32, "i16x8.extract_lane"#sign,
+                            !add(baseInst, 2),
+                            !cast<PatFrag>("extract_i16x8"#sign)>;
+}
+
+let Defs = [ARGUMENTS] in {
+defm EXTRACT_LANE_S : ExtractLaneExtended<"_s", 9>;
+defm EXTRACT_LANE_U : ExtractLaneExtended<"_u", 10>;
+defm EXTRACT_LANE_I32x4 :
+    ExtractLane<v4i32, LaneIdx4, I32, "i32x4.extract_lane", 13>;
+defm EXTRACT_LANE_I64x2 :
+    ExtractLane<v2i64, LaneIdx2, I64, "i64x2.extract_lane", 14>;
+defm EXTRACT_LANE_F32x4 :
+    ExtractLane<v4f32, LaneIdx4, F32, "f32x4.extract_lane", 15>;
+defm EXTRACT_LANE_F64x2 :
+    ExtractLane<v2f64, LaneIdx2, F64, "f64x2.extract_lane", 16>;
+} // Defs = [ARGUMENTS]
+
+// follow convention of making implicit expansions unsigned
+def : Pat<(i32 (vector_extract (v16i8 V128:$vec), (i32 LaneIdx16:$idx))),
+          (EXTRACT_LANE_U_I8x16 V128:$vec, (i32 LaneIdx16:$idx))>;
+def : Pat<(i32 (vector_extract (v8i16 V128:$vec), (i32 LaneIdx8:$idx))),
+          (EXTRACT_LANE_U_I16x8 V128:$vec, (i32 LaneIdx8:$idx))>;
+
+// arithmetic
+let Defs = [ARGUMENTS] in {
 let isCommutable = 1 in
 defm ADD : SIMDBinaryInt<add, "add ", 24>;
 defm SUB : SIMDBinaryInt<sub, "sub ", 28>;
 let isCommutable = 1 in
 defm MUL : SIMDBinaryInt<mul, "mul ", 32>;
-
 let isCommutable = 1 in
 defm ADD : SIMDBinaryFP<fadd, "add ", 122>;
 defm SUB : SIMDBinaryFP<fsub, "sub ", 124>;
 defm DIV : SIMDBinaryFP<fdiv, "div ", 126>;
 let isCommutable = 1 in
 defm MUL : SIMDBinaryFP<fmul, "mul ", 128>;
-
 } // Defs = [ARGUMENTS]