Merge branch 'master' into prototype-fmt

1 files changed, 127 insertions, 4 deletions

diff --git a/src/llvm_backend_opt.cpp b/src/llvm_backend_opt.cpp
index 3b268dffa..213005f8f 100644
--- a/src/llvm_backend_opt.cpp
+++ b/src/llvm_backend_opt.cpp
@@ -1,7 +1,25 @@
-void lb_populate_function_pass_manager(LLVMPassManagerRef fpm, bool ignore_memcpy_pass, i32 optimization_level);
+void lb_populate_function_pass_manager(lbModule *m, LLVMPassManagerRef fpm, bool ignore_memcpy_pass, i32 optimization_level);
 void lb_add_function_simplifcation_passes(LLVMPassManagerRef mpm, i32 optimization_level);
 void lb_populate_module_pass_manager(LLVMTargetMachineRef target_machine, LLVMPassManagerRef mpm, i32 optimization_level);
-void lb_populate_function_pass_manager_specific(LLVMPassManagerRef fpm, i32 optimization_level);
+void lb_populate_function_pass_manager_specific(lbModule *m, LLVMPassManagerRef fpm, i32 optimization_level);
+
+LLVMBool lb_must_preserve_predicate_callback(LLVMValueRef value, void *user_data) {
+	lbModule *m = cast(lbModule *)user_data;
+	if (m == nullptr) {
+		return false;
+	}
+	if (value == nullptr) {
+		return false;
+	}
+	return LLVMIsAAllocaInst(value) != nullptr;
+}
+
+void lb_add_must_preserve_predicate_pass(lbModule *m, LLVMPassManagerRef fpm, i32 optimization_level) {
+	if (false && optimization_level == 0 && m->debug_builder) {
+		// LLVMAddInternalizePassWithMustPreservePredicate(fpm, m, lb_must_preserve_predicate_callback);
+	}
+}
+
 
 void lb_basic_populate_function_pass_manager(LLVMPassManagerRef fpm) {
 	LLVMAddPromoteMemoryToRegisterPass(fpm);
@@ -15,11 +33,13 @@ void lb_basic_populate_function_pass_manager(LLVMPassManagerRef fpm) {
 	LLVMAddCFGSimplificationPass(fpm);
 }
 
-void lb_populate_function_pass_manager(LLVMPassManagerRef fpm, bool ignore_memcpy_pass, i32 optimization_level) {
+void lb_populate_function_pass_manager(lbModule *m, LLVMPassManagerRef fpm, bool ignore_memcpy_pass, i32 optimization_level) {
 	// NOTE(bill): Treat -opt:3 as if it was -opt:2
 	// TODO(bill): Determine which opt definitions should exist in the first place
 	optimization_level = gb_clamp(optimization_level, 0, 2);
 
+	lb_add_must_preserve_predicate_pass(m, fpm, optimization_level);
+
 	if (ignore_memcpy_pass) {
 		lb_basic_populate_function_pass_manager(fpm);
 		return;
@@ -57,11 +77,13 @@ void lb_populate_function_pass_manager(LLVMPassManagerRef fpm, bool ignore_memcp
 #endif
 }
 
-void lb_populate_function_pass_manager_specific(LLVMPassManagerRef fpm, i32 optimization_level) {
+void lb_populate_function_pass_manager_specific(lbModule *m, LLVMPassManagerRef fpm, i32 optimization_level) {
 	// NOTE(bill): Treat -opt:3 as if it was -opt:2
 	// TODO(bill): Determine which opt definitions should exist in the first place
 	optimization_level = gb_clamp(optimization_level, 0, 2);
 
+	lb_add_must_preserve_predicate_pass(m, fpm, optimization_level);
+
 	if (optimization_level == 0) {
 		LLVMAddMemCpyOptPass(fpm);
 		lb_basic_populate_function_pass_manager(fpm);
@@ -226,3 +248,104 @@ void lb_populate_module_pass_manager(LLVMTargetMachineRef target_machine, LLVMPa
 
 	LLVMAddCFGSimplificationPass(mpm);
 }
+
+void lb_run_remove_dead_instruction_pass(lbProcedure *p) {
+	isize removal_count = 0;
+	isize pass_count = 0;
+	isize const max_pass_count = 10;
+	isize original_instruction_count = 0;
+	// Custom remove dead instruction pass
+	for (; pass_count < max_pass_count; pass_count++) {
+		bool was_dead_instructions = false;
+
+		// NOTE(bill): Iterate backwards
+		// reduces the number of passes as things later on will depend on things previously
+		for (LLVMBasicBlockRef block = LLVMGetLastBasicBlock(p->value);
+		     block != nullptr;
+		     block = LLVMGetPreviousBasicBlock(block)) {
+			// NOTE(bill): Iterate backwards
+			// reduces the number of passes as things later on will depend on things previously
+			for (LLVMValueRef instr = LLVMGetLastInstruction(block);
+			     instr != nullptr;
+			     /**/)  {
+			     	if (pass_count == 0) {
+			     		original_instruction_count += 1;
+			     	}
+
+				LLVMValueRef curr_instr = instr;
+				instr = LLVMGetPreviousInstruction(instr);
+
+				LLVMUseRef first_use = LLVMGetFirstUse(curr_instr);
+				if (first_use != nullptr)  {
+					continue;
+				}
+				if (LLVMTypeOf(curr_instr) == nullptr) {
+					continue;
+				}
+
+				// NOTE(bill): Explicit instructions are set here because some instructions could have side effects
+				switch (LLVMGetInstructionOpcode(curr_instr)) {
+				case LLVMFNeg:
+				case LLVMAdd:
+				case LLVMFAdd:
+				case LLVMSub:
+				case LLVMFSub:
+				case LLVMMul:
+				case LLVMFMul:
+				case LLVMUDiv:
+				case LLVMSDiv:
+				case LLVMFDiv:
+				case LLVMURem:
+				case LLVMSRem:
+				case LLVMFRem:
+				case LLVMShl:
+				case LLVMLShr:
+				case LLVMAShr:
+				case LLVMAnd:
+				case LLVMOr:
+				case LLVMXor:
+				case LLVMAlloca:
+				case LLVMLoad:
+				case LLVMGetElementPtr:
+				case LLVMTrunc:
+				case LLVMZExt:
+				case LLVMSExt:
+				case LLVMFPToUI:
+				case LLVMFPToSI:
+				case LLVMUIToFP:
+				case LLVMSIToFP:
+				case LLVMFPTrunc:
+				case LLVMFPExt:
+				case LLVMPtrToInt:
+				case LLVMIntToPtr:
+				case LLVMBitCast:
+				case LLVMAddrSpaceCast:
+				case LLVMICmp:
+				case LLVMFCmp:
+				case LLVMSelect:
+				case LLVMExtractElement:
+				case LLVMShuffleVector:
+				case LLVMExtractValue:
+					removal_count += 1;
+					LLVMInstructionEraseFromParent(curr_instr);
+					was_dead_instructions = true;
+					break;
+				}
+			}
+		}
+
+		if (!was_dead_instructions) {
+			break;
+		}
+	}
+}
+
+
+void lb_run_function_pass_manager(LLVMPassManagerRef fpm, lbProcedure *p) {
+	LLVMRunFunctionPassManager(fpm, p->value);
+	// NOTE(bill): LLVMAddDCEPass doesn't seem to be exported in the official DLL's for LLVM
+	// which means we cannot rely upon it
+	// This is also useful for read the .ll for debug purposes because a lot of instructions
+	// are not removed
+	lb_run_remove_dead_instruction_pass(p);
+}