Sema: implement peer type resolution of signed and unsigned ints

This allows stage2 to build more of compiler-rt.

I also changed `-%` to `-` for comptime ints in the div and mul
implementations of compiler-rt. This is clearer code and also happens to
work around a bug in stage2.

2 files changed, 14 insertions, 13 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index b65e88360f..42bf795bd9 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -14634,11 +14634,11 @@ fn resolvePeerTypes(
     instructions: []Air.Inst.Ref,
     candidate_srcs: Module.PeerTypeCandidateSrc,
 ) !Type {
-    if (instructions.len == 0)
-        return Type.initTag(.noreturn);
-
-    if (instructions.len == 1)
-        return sema.typeOf(instructions[0]);
+    switch (instructions.len) {
+        0 => return Type.initTag(.noreturn),
+        1 => return sema.typeOf(instructions[0]),
+        else => {},
+    }
 
     const target = sema.mod.getTarget();
 
@@ -14668,13 +14668,14 @@ fn resolvePeerTypes(
                     continue;
                 },
                 .Int => {
-                    if (chosen_ty.isSignedInt() == candidate_ty.isSignedInt()) {
-                        if (chosen_ty.intInfo(target).bits < candidate_ty.intInfo(target).bits) {
-                            chosen = candidate;
-                            chosen_i = candidate_i + 1;
-                        }
-                        continue;
+                    const chosen_info = chosen_ty.intInfo(target);
+                    const candidate_info = candidate_ty.intInfo(target);
+
+                    if (chosen_info.bits < candidate_info.bits) {
+                        chosen = candidate;
+                        chosen_i = candidate_i + 1;
                     }
+                    continue;
                 },
                 .Pointer => if (chosen_ty.ptrSize() == .C) continue,
                 else => {},
diff --git a/src/type.zig b/src/type.zig
index 9de6bb25a8..b948093994 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -3106,9 +3106,9 @@ pub const Type = extern union {
             .c_ulonglong => return .{ .signedness = .unsigned, .bits = CType.ulonglong.sizeInBits(target) },
 
             .enum_full, .enum_nonexhaustive => ty = ty.cast(Payload.EnumFull).?.data.tag_ty,
-            .enum_numbered => ty = self.castTag(.enum_numbered).?.data.tag_ty,
+            .enum_numbered => ty = ty.castTag(.enum_numbered).?.data.tag_ty,
             .enum_simple => {
-                const enum_obj = self.castTag(.enum_simple).?.data;
+                const enum_obj = ty.castTag(.enum_simple).?.data;
                 const field_count = enum_obj.fields.count();
                 if (field_count == 0) return .{ .signedness = .unsigned, .bits = 0 };
                 return .{ .signedness = .unsigned, .bits = smallestUnsignedBits(field_count - 1) };