From 445dd65c78dbef15fe6f53253dc3d0ce01939eb0 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Tue, 17 May 2022 17:30:04 +0300
Subject: [PATCH] Improve argument passing

---
 ir_x86.dasc              | 32 +++++++++++++++++++++++---------
 tests/debug/args_001.irt |  6 +++---
 tests/debug/args_002.irt | 29 ++++++++++++++---------------
 3 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/ir_x86.dasc b/ir_x86.dasc
index 4d78dd6..f7c471c 100644
--- a/ir_x86.dasc
+++ b/ir_x86.dasc
@@ -733,9 +733,11 @@ ir_reg ir_uses_fixed_reg(ir_ctx *ctx, ir_ref ref, int op_num)
 	return IR_REG_NONE;
 }
 
-static bool ir_may_need_tmp_reg_for_int_args_swap(ir_ctx *ctx, ir_ref ref)
+static bool ir_call_needs_tmp_int_reg(ir_ctx *ctx, ir_ref ref)
 {
 	ir_insn *insn = &ctx->ir_base[ref];
+	ir_ref arg;
+	ir_insn *arg_insn;
 	int j, n;
 	ir_type type;
 	int int_param = 0;
@@ -743,16 +745,22 @@ static bool ir_may_need_tmp_reg_for_int_args_swap(ir_ctx *ctx, ir_ref ref)
 
 	n = ir_input_edges_count(ctx, insn);
 	for (j = 3; j <= n; j++) {
-		type = ctx->ir_base[insn->ops[j]].type;
+		arg = insn->ops[j];
+		arg_insn = &ctx->ir_base[arg];
+		type = arg_insn->type;
 		if (IR_IS_TYPE_INT(type)) {
 			if (int_param < int_reg_params_count) {
 				if (int_param > 0) {
-					return 1;
+					return 1; /* for swap */
 				}
 			} else {
 				return 0;
 			}
 			int_param++;
+		} else if (type == IR_DOUBLE) {
+			if (IR_IS_CONST_REF(arg) && arg_insn->val.i64 != 0) {
+				return 1;
+			}
 		}
 	}
 	return 0;
@@ -1012,7 +1020,7 @@ cmp_fp:
 			return n;
 		case IR_CALL:
 		case IR_TAILCALL:
-			if (ir_may_need_tmp_reg_for_int_args_swap(ctx, ref)) {
+			if (ir_call_needs_tmp_int_reg(ctx, ref)) {
 				tmp_regs[0].num = 1;
 				tmp_regs[0].type = IR_ADDR;
 				tmp_regs[0].start = IR_LOAD_SUB_REF;
@@ -3619,7 +3627,7 @@ static int32_t ir_emit_arguments(ir_ctx *ctx, ir_ref def, ir_insn *insn, ir_reg
 	} else {
 		used_stack = ir_call_used_stack(ctx, insn);
 		if (used_stack) {
-			|	lea rsp, [rsp-used_stack]
+			|	sub rsp, used_stack
 		}
 	}
 
@@ -3690,16 +3698,22 @@ static int32_t ir_emit_arguments(ir_ctx *ctx, ir_ref def, ir_insn *insn, ir_reg
 				}
 			} else {
 				if (IR_IS_CONST_REF(arg)) {
-					ir_emit_load(ctx, type, tmp_fp_reg, arg);
-					src_reg = tmp_fp_reg;
+					ir_val *val = &ctx->ir_base[arg].val;
+					if (ir_type_size[type] == 4 || val->i64 == 0) {
+						|	mov qword [rsp+stack_offset], val->i32
+					} else {
+						IR_ASSERT(tmp_reg != IR_REG_NONE);
+						|	mov64 Rq(tmp_reg), val->i64
+						|	mov qword [rsp+stack_offset], Ra(tmp_reg)
+					}
 				} else {
 					IR_ASSERT(src_reg != IR_REG_NONE);
 					if (src_reg & IR_REG_SPILL_LOAD) {
 						src_reg &= ~IR_REG_SPILL_LOAD;
 						ir_emit_load(ctx, type, src_reg, arg);
 					}
+					|	ASM_FP_MEM_REG_OP movss, movsd, vmovss, vmovsd, type, [rsp+stack_offset], src_reg
 				}
-				|	ASM_FP_MEM_REG_OP movss, movsd, vmovss, vmovsd, type, [rsp+stack_offset], src_reg
 			}
 			stack_offset += sizeof(void*);
 		}
@@ -3783,7 +3797,7 @@ static void ir_emit_call(ir_ctx *ctx, ir_ref def, ir_insn *insn)
     }
 
 	if (used_stack) {
-		|	lea rsp, [rsp+used_stack]
+		|	add rsp, used_stack
 	}
 
 	if (insn->type != IR_VOID) {
diff --git a/tests/debug/args_001.irt b/tests/debug/args_001.irt
index 165b953..768559d 100644
--- a/tests/debug/args_001.irt
+++ b/tests/debug/args_001.irt
@@ -23,14 +23,14 @@
 --EXPECT--
 test:
 	subq $8, %rsp
-	leaq -0x30(%rsp), %rsp
+	subq $0x30, %rsp
 	movl $6, (%rsp)
 	movl $7, 8(%rsp)
 	movl $8, 0x10(%rsp)
 	movq $9, 0x18(%rsp)
 	movabsq $0x100000000, %rax
 	movq %rax, 0x20(%rsp)
-	leaq 0x39(%rip), %rdi
+	leaq 0x3a(%rip), %rdi
 	movq $1, %rsi
 	movw $2, %dx
 	movl $3, %ecx
@@ -38,7 +38,7 @@ test:
 	movabsq $0x100000000, %r9
 	movabsq $_IO_printf, %rax
 	callq *%rax
-	leaq 0x30(%rsp), %rsp
+	addq $0x30, %rsp
 	addq $8, %rsp
 	retq
 
diff --git a/tests/debug/args_002.irt b/tests/debug/args_002.irt
index 279749f..a673d1b 100644
--- a/tests/debug/args_002.irt
+++ b/tests/debug/args_002.irt
@@ -23,23 +23,22 @@
 --EXPECT--
 test:
 	subq $8, %rsp
-	leaq -0x10(%rsp), %rsp
-	movsd 0xb6(%rip), %xmm15
-	movsd %xmm15, (%rsp)
-	xorpd %xmm15, %xmm15
-	movsd %xmm15, 8(%rsp)
-	leaq 0xa5(%rip), %rdi
-	movsd 0x55(%rip), %xmm0
-	movsd 0x55(%rip), %xmm1
-	movsd 0x55(%rip), %xmm2
-	movsd 0x55(%rip), %xmm3
-	movsd 0x55(%rip), %xmm4
-	movsd 0x55(%rip), %xmm5
-	movsd 0x55(%rip), %xmm6
-	movsd 0x55(%rip), %xmm7
+	subq $0x10, %rsp
+	movabsq $0x3feccccccccccccd, %rax
+	movq %rax, (%rsp)
+	movq $0, 8(%rsp)
+	leaq 0x9a(%rip), %rdi
+	movsd 0x52(%rip), %xmm0
+	movsd 0x52(%rip), %xmm1
+	movsd 0x52(%rip), %xmm2
+	movsd 0x52(%rip), %xmm3
+	movsd 0x52(%rip), %xmm4
+	movsd 0x52(%rip), %xmm5
+	movsd 0x52(%rip), %xmm6
+	movsd 0x52(%rip), %xmm7
 	movabsq $_IO_printf, %rax
 	callq *%rax
-	leaq 0x10(%rsp), %rsp
+	addq $0x10, %rsp
 	addq $8, %rsp
 	retq