[Liftoff] Add integer conversions

This adds support for i32.wrap/i64, i64.extend_s/i32, and
i64.extend_u/i32.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: Iaeac1d24a53d044151cb244fffe3eab04314d908
Reviewed-on: https://chromium-review.googlesource.com/962281
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51930}

src/wasm/baseline/ia32/liftoff-assembler-ia32.h

@@ -696,9 +696,21 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
                                             LiftoffRegister dst,
                                             LiftoffRegister src) {
   switch (opcode) {
+    case kExprI32ConvertI64:
+      if (dst.gp() != src.low_gp()) mov(dst.gp(), src.low_gp());
+      return true;
     case kExprI32ReinterpretF32:
       Movd(dst.gp(), src.fp());
       return true;
+    case kExprI64SConvertI32:
+      if (dst.low_gp() != src.gp()) mov(dst.low_gp(), src.gp());
+      mov(dst.high_gp(), src.gp());
+      sar(dst.high_gp(), 31);
+      return true;
+    case kExprI64UConvertI32:
+      if (dst.low_gp() != src.gp()) mov(dst.low_gp(), src.gp());
+      xor_(dst.high_gp(), dst.high_gp());
+      return true;
     case kExprI64ReinterpretF64:
       // Push src to the stack.
       sub(esp, Immediate(8));

src/wasm/baseline/liftoff-compiler.cc

@@ -625,7 +625,10 @@ class LiftoffCompiler {
         CASE_FLOAT_UNOP(F32Sqrt, F32, f32_sqrt)
         CASE_FLOAT_UNOP(F64Neg, F64, f64_neg)
         CASE_FLOAT_UNOP(F64Sqrt, F64, f64_sqrt)
+        CASE_TYPE_CONVERSION(I32ConvertI64, I32, I64, nullptr)
         CASE_TYPE_CONVERSION(I32ReinterpretF32, I32, F32, nullptr)
+        CASE_TYPE_CONVERSION(I64SConvertI32, I64, I32, nullptr)
+        CASE_TYPE_CONVERSION(I64UConvertI32, I64, I32, nullptr)
         CASE_TYPE_CONVERSION(I64ReinterpretF64, I64, F64, nullptr)
         CASE_TYPE_CONVERSION(F32SConvertI32, F32, I32, nullptr)
         CASE_TYPE_CONVERSION(F32UConvertI32, F32, I32, nullptr)

src/wasm/baseline/x64/liftoff-assembler-x64.h

@@ -643,9 +643,19 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
                                             LiftoffRegister dst,
                                             LiftoffRegister src) {
   switch (opcode) {
+    case kExprI32ConvertI64:
+      movl(dst.gp(), src.gp());
+      return true;
     case kExprI32ReinterpretF32:
       Movd(dst.gp(), src.fp());
       return true;
+    case kExprI64SConvertI32:
+      movsxlq(dst.gp(), src.gp());
+      return true;
+    case kExprI64UConvertI32:
+      if (dst.gp() != src.gp()) movl(dst.gp(), src.gp());
+      // TODO(clemensh): Add assertion that the upper 32 bit are zero.
+      return true;
     case kExprI64ReinterpretF64:
       Movq(dst.gp(), src.fp());
       return true;