From e445c0d63e788fba46a41c1241e6b312423b7f21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Wed, 6 May 2026 20:55:36 +0200
Subject: [PATCH] zig cc: always enforce -mabi=ieeelongdouble for powerpc

closes https://codeberg.org/ziglang/zig/issues/30976
---
 src/Compilation.zig | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/Compilation.zig b/src/Compilation.zig
index 3a70e05f5dde53b1f58911096b233b1c05c9c2b0..d69813fd1120bf1384b4e16cd62dfc3679ac8f6f 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -6639,6 +6639,19 @@ pub fn addCCArgs(
         }
     }
 
+    if (target.cpu.arch.isPowerPC()) {
+        // We do not -- and probably never will -- support the IBM 128-bit `long double` format.
+        // LLVM and Clang also do not have complete support for it, producing wrong values in some
+        // cases. So just enforce IEEE `long double` everywhere - either binary64 or binary128
+        // depending on what the OS/ABI requires.
+        try argv.appendSlice(&.{
+            "-mabi=ieeelongdouble",
+            // Clang has some truly goofy logic for emitting warnings about the
+            // "current library" not supporting IEEE `long double`.
+            "-Wno-unsupported-abi",
+        });
+    }
+
     // We might want to support -mfloat-abi=softfp for Arm and CSKY here in the future.
     if (target_util.clangSupportsFloatAbiArg(target)) {
         const fabi = @tagName(target.abi.float());
-- 
2.54.0