[Liftoff] Implement i32/i64 to f64 conversions

After the refactoring for supporting f32 conversions, adding f64
conversions is straight forward.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: I8f76fbef3f1e67ecdb02dd1d103868f2d1d3226f
Reviewed-on: https://chromium-review.googlesource.com/957026
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51864}

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

@@ -707,6 +707,12 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
       Cvtui2ss(dst.fp(), src.gp(), scratch);
       return true;
     }
+    case kExprF64SConvertI32:
+      Cvtsi2sd(dst.fp(), src.gp());
+      return true;
+    case kExprF64UConvertI32:
+      LoadUint32(dst.fp(), src.gp());
+      return true;
     default:
       return false;
   }

src/wasm/baseline/liftoff-compiler.cc

@@ -514,7 +514,8 @@ class LiftoffCompiler {
         __ SetCCallStackParamAddr(num_stack_params, num_lowered_args, arg_type);
         ++num_stack_params;
       }
-      num_lowered_args += 1 + needs_reg_pair(arg_type);
+      num_lowered_args +=
+          RoundUp<kPointerSize>(WasmOpcodes::MemSize(arg_type)) / kPointerSize;
       ++input_idx;
     };
     for (ValueType arg_type : sig->parameters()) {
@@ -637,6 +638,12 @@ class LiftoffCompiler {
                              &ExternalReference::wasm_int64_to_float32)
         CASE_TYPE_CONVERSION(F32UConvertI64, F32, I64,
                              &ExternalReference::wasm_uint64_to_float32)
+        CASE_TYPE_CONVERSION(F64SConvertI32, F64, I32, nullptr)
+        CASE_TYPE_CONVERSION(F64UConvertI32, F64, I32, nullptr)
+        CASE_TYPE_CONVERSION(F64SConvertI64, F64, I64,
+                             &ExternalReference::wasm_int64_to_float64)
+        CASE_TYPE_CONVERSION(F64UConvertI64, F64, I64,
+                             &ExternalReference::wasm_uint64_to_float64)
       default:
         return unsupported(decoder, WasmOpcodes::OpcodeName(opcode));
     }

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

@@ -658,6 +658,19 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
     case kExprF32UConvertI64:
       Cvtqui2ss(dst.fp(), src.gp(), kScratchRegister);
       return true;
+    case kExprF64SConvertI32:
+      Cvtlsi2sd(dst.fp(), src.gp());
+      return true;
+    case kExprF64UConvertI32:
+      movl(kScratchRegister, src.gp());
+      Cvtqsi2sd(dst.fp(), kScratchRegister);
+      return true;
+    case kExprF64SConvertI64:
+      Cvtqsi2sd(dst.fp(), src.gp());
+      return true;
+    case kExprF64UConvertI64:
+      Cvtqui2sd(dst.fp(), src.gp(), kScratchRegister);
+      return true;
     default:
       UNREACHABLE();
   }