From 74ac336ef1905d487aee85536fb21a173afe2127 Mon Sep 17 00:00:00 2001
From: Mihail Moskov <28909106+corleypc@users.noreply.github.com>
Date: Mon, 24 Aug 2026 12:53:05 +0300
Subject: [PATCH] fixes -o:size

---
 src/build_settings.cpp       | 9 +++++++++
 src/llvm_backend.cpp         | 1 +
 src/llvm_backend_general.cpp | 4 ++++
 src/llvm_backend_proc.cpp    | 7 +++++++
 4 files changed, 21 insertions(+)

diff --git a/src/build_settings.cpp b/src/build_settings.cpp
index 453934949..714b8af8f 100644
--- a/src/build_settings.cpp
+++ b/src/build_settings.cpp
@@ -464,6 +464,15 @@ enum IntegerDivisionByZeroKind : u8 {
 	IntegerDivisionByZero_AllBits,
 };
 
+// values of BuildContext.optimization_level;
+// matches Odin_Optimization_Mode in checker.cpp
+enum OptimizationLevel : i32 {
+	OptimizationLevel_None       = -1,
+	OptimizationLevel_Minimal    =  0,
+	OptimizationLevel_Size       =  1,
+	OptimizationLevel_Speed      =  2,
+	OptimizationLevel_Aggressive =  3,
+};
 
 // This stores the information for the specify architecture of this build
 struct BuildContext {
diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp
index 07f118f20..e770ed90d 100644
--- a/src/llvm_backend.cpp
+++ b/src/llvm_backend.cpp
@@ -2438,6 +2438,7 @@ gb_internal WORKER_TASK_PROC(lb_llvm_function_pass_per_module) {
 			lbFunctionPassManagerKind pass_manager_kind = lbFunctionPassManager_default;
 			if (p->flags & lbProcedureFlag_WithoutMemcpyPass) {
 				pass_manager_kind = lbFunctionPassManager_default_without_memcpy;
+				lb_remove_attribute_from_proc(p->module, p->value, "optsize"); // incompatible with optnone
 				lb_add_attribute_to_proc(p->module, p->value, "optnone");
 				lb_add_attribute_to_proc(p->module, p->value, "noinline");
 			} else {
diff --git a/src/llvm_backend_general.cpp b/src/llvm_backend_general.cpp
index 5c77e58df..17b41cfad 100644
--- a/src/llvm_backend_general.cpp
+++ b/src/llvm_backend_general.cpp
@@ -3033,6 +3033,10 @@ gb_internal void lb_add_attribute_to_proc(lbModule *m, LLVMValueRef proc_value,
 	LLVMAddAttributeAtIndex(proc_value, LLVMAttributeIndex_FunctionIndex, lb_create_enum_attribute(m->ctx, name, value));
 }
 
+gb_internal void lb_remove_attribute_from_proc(lbModule *m, LLVMValueRef proc_value, char const *name) {
+	LLVMRemoveEnumAttributeAtIndex(proc_value, LLVMAttributeIndex_FunctionIndex, LLVMGetEnumAttributeKindForName(name, gb_strlen(name)));
+}
+
 gb_internal bool lb_proc_has_attribute(lbModule *m, LLVMValueRef proc_value, char const *name) {
 	LLVMAttributeRef ref = LLVMGetEnumAttributeAtIndex(proc_value, LLVMAttributeIndex_FunctionIndex, LLVMGetEnumAttributeKindForName(name, gb_strlen(name)));
 	return ref != nullptr;
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 4c7a0fb44..42c2f8653 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -213,6 +213,13 @@ gb_internal lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool i
 	case ProcedureOptimizationMode_FavorSize:
 		lb_add_attribute_to_proc(m, p->value, "optsize");
 		break;
+	default:
+		// need optsize per proc for -o:size;
+		// (inliner, unroller, vectorizer, etc check it) 
+		if (build_context.optimization_level == OptimizationLevel_Size) {
+			lb_add_attribute_to_proc(m, p->value, "optsize");
+		}
+		break;
 	}
 
 	if (pt->Proc.enable_target_feature.len != 0) {