From a7da54516a27171d27a6c4b8bad6f4621a5f3e2e Mon Sep 17 00:00:00 2001
From: Richard Feldman <oss@rtfeldman.com>
Date: Mon, 12 Oct 2020 17:59:19 -0400
Subject: [PATCH] Cast i64 to f64 instead of using builtin bitcode

---
 compiler/builtins/bitcode/src/lib.rs | 4 ++--
 compiler/gen/src/llvm/build.rs       | 9 +++++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/compiler/builtins/bitcode/src/lib.rs b/compiler/builtins/bitcode/src/lib.rs
index 57dfd48ba8..b64bbf6580 100644
--- a/compiler/builtins/bitcode/src/lib.rs
+++ b/compiler/builtins/bitcode/src/lib.rs
@@ -6,8 +6,8 @@
 
 mod libm;
 
-/// TODO replace this with a normal Inkwell build_cast call - this was just
-/// used as a proof of concept for getting bitcode importing working!
+/// TODO this is no longer used. Feel free to delete it the next time
+/// we need to rebuild builtins.bc!
 #[no_mangle]
 pub fn i64_to_f64_(num: i64) -> f64 {
     num as f64
diff --git a/compiler/gen/src/llvm/build.rs b/compiler/gen/src/llvm/build.rs
index 2d422b8f79..8404ddb0a3 100644
--- a/compiler/gen/src/llvm/build.rs
+++ b/compiler/gen/src/llvm/build.rs
@@ -2619,8 +2619,13 @@ fn build_int_unary_op<'a, 'ctx, 'env>(
             ))
         }
         NumToFloat => {
-            // TODO specialize this to be not just for i64!
-            call_bitcode_fn(NumToFloat, env, &[arg.into()], "i64_to_f64_")
+            // This is an Int, so we need to convert it.
+            bd.build_cast(
+                InstructionOpcode::SIToFP,
+                arg,
+                env.context.f64_type(),
+                "i64_to_f64",
+            )
         }
         _ => {
             unreachable!("Unrecognized int unary operation: {:?}", op);