From 35c9b717f752ceb1a031e0bcfc237a9c4f3bf6ad Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly0@users.noreply.github.com>
Date: Sun, 8 Oct 2023 03:27:12 -0400
Subject: [PATCH] x86_64: implement `@rem` for floats

---
 src/arch/x86_64/CodeGen.zig | 13 +++++++++----
 test/behavior/math.zig      |  3 ++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
index 46682345b9..b2ba2ac93a 100644
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -6831,12 +6831,12 @@ fn genBinOp(
     const rhs_ty = self.typeOf(rhs_air);
     const abi_size: u32 = @intCast(lhs_ty.abiSize(mod));
 
-    if (lhs_ty.isRuntimeFloat() and switch (lhs_ty.floatBits(self.target.*)) {
+    if (lhs_ty.isRuntimeFloat() and (air_tag == .rem or switch (lhs_ty.floatBits(self.target.*)) {
         16 => !self.hasFeature(.f16c),
         32, 64 => false,
         80, 128 => true,
         else => unreachable,
-    }) {
+    })) {
         var callee: ["__add?f3".len]u8 = undefined;
         const result = try self.genCall(.{ .lib = .{
             .return_type = lhs_ty.toIntern(),
@@ -6852,9 +6852,14 @@ fn genBinOp(
                     @tagName(air_tag)[0..3],
                     floatCompilerRtAbiName(lhs_ty.floatBits(self.target.*)),
                 }),
-                .min, .max => std.fmt.bufPrint(&callee, "{s}f{s}{s}", .{
+                .rem, .min, .max => std.fmt.bufPrint(&callee, "{s}f{s}{s}", .{
                     floatLibcAbiPrefix(lhs_ty),
-                    @tagName(air_tag),
+                    switch (air_tag) {
+                        .rem => "mod",
+                        .min => "min",
+                        .max => "max",
+                        else => unreachable,
+                    },
                     floatLibcAbiSuffix(lhs_ty),
                 }),
                 else => return self.fail("TODO implement genBinOp for {s} {}", .{
diff --git a/test/behavior/math.zig b/test/behavior/math.zig
index e017a62aa6..7acbe4de3f 100644
--- a/test/behavior/math.zig
+++ b/test/behavior/math.zig
@@ -1332,6 +1332,7 @@ test "remainder division" {
     try comptime remdiv(f80);
     try comptime remdiv(f128);
     try remdiv(f16);
+    try remdiv(f32);
     try remdiv(f64);
     try remdiv(f80);
     try remdiv(f128);
@@ -1356,7 +1357,7 @@ test "float remainder division using @rem" {
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
-    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_x86_64 and builtin.target.ofmt != .elf) return error.SkipZigTest;
 
     try comptime frem(f16);
     try comptime frem(f32);