From ca4ee9ae73559062da24937ef4a7376d9d27bbeb Mon Sep 17 00:00:00 2001
From: amp-59 <114923809+amp-59@users.noreply.github.com>
Date: Wed, 3 Jan 2024 07:34:24 +0000
Subject: [PATCH] Sema: Added logic to avoid unchecked operations calling
 `preparePanicId` (#18416)

Fixes #18415
---
 src/Sema.zig                                     |  5 ++++-
 .../no_compile_panic_for_unchecked_arith.zig     | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 test/cases/no_compile_panic_for_unchecked_arith.zig

diff --git a/src/Sema.zig b/src/Sema.zig
index 0c464a0bc1..c0b6f3678a 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -16019,9 +16019,12 @@ fn analyzeArithmetic(
     };
 
     try sema.requireRuntimeBlock(block, src, runtime_src);
+
     if (block.wantSafety() and want_safety and scalar_tag == .Int) {
         if (mod.backendSupportsFeature(.safety_checked_instructions)) {
-            _ = try sema.preparePanicId(block, .integer_overflow);
+            if (air_tag != air_tag_safe) {
+                _ = try sema.preparePanicId(block, .integer_overflow);
+            }
             return block.addBinOp(air_tag_safe, casted_lhs, casted_rhs);
         } else {
             const maybe_op_ov: ?Air.Inst.Tag = switch (air_tag) {
diff --git a/test/cases/no_compile_panic_for_unchecked_arith.zig b/test/cases/no_compile_panic_for_unchecked_arith.zig
new file mode 100644
index 0000000000..a9aa8272b1
--- /dev/null
+++ b/test/cases/no_compile_panic_for_unchecked_arith.zig
@@ -0,0 +1,16 @@
+pub const panic = @compileError("");
+
+export fn entry() usize {
+    var x: usize = 0;
+    x +%= 1;
+    x -%= 1;
+    x *%= 2;
+    x +|= 1;
+    x -|= 1;
+    x *|= 2;
+    return x;
+}
+
+// compile
+// output_mode=Obj
+// backend=stage2,llvm