optimise inc/dec; jcc

src/rust/codegen.rs

@@ -1698,7 +1698,13 @@ pub fn gen_getzf(ctx: &mut JitContext, negate: ConditionNegate) {
 
 pub fn gen_getcf(ctx: &mut JitContext, negate: ConditionNegate) {
     match &ctx.previous_instruction {
-        Instruction::Cmp { source, opsize, .. } | Instruction::Sub { source, opsize, .. } => {
+        Instruction::Cmp { source, opsize, .. }
+        | Instruction::Sub {
+            source,
+            opsize,
+            is_dec: false,
+            ..
+        } => {
             // Note: x < y and x < x - y can be used interchangeably (see getcf)
             gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
             gen_get_last_op1(ctx.builder, &ctx.previous_instruction);
@@ -1714,7 +1720,12 @@ pub fn gen_getcf(ctx: &mut JitContext, negate: ConditionNegate) {
                 ctx.builder.ltu_i32();
             }
         },
-        Instruction::Add { source, opsize, .. } => {
+        Instruction::Add {
+            source,
+            opsize,
+            is_inc: false,
+            ..
+        } => {
             gen_get_last_result(ctx.builder, &ctx.previous_instruction);
             match (opsize, source) {
                 (&OPSIZE_32, InstructionOperand::WasmLocal(l)) => ctx.builder.get_local(l),
@@ -1728,6 +1739,14 @@ pub fn gen_getcf(ctx: &mut JitContext, negate: ConditionNegate) {
                 ctx.builder.ltu_i32();
             }
         },
+        Instruction::Add { is_inc: true, .. } | Instruction::Sub { is_dec: true, .. } => {
+            gen_get_flags(ctx.builder);
+            ctx.builder.const_i32(FLAG_CARRY);
+            ctx.builder.and_i32();
+            if negate == ConditionNegate::True {
+                ctx.builder.eqz_i32();
+            }
+        },
         _ => {
             gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_UNOPTIMISED);
             gen_getcf_unoptimised(ctx);
@@ -1983,8 +2002,9 @@ pub fn gen_test_be(ctx: &mut JitContext, negate: ConditionNegate) {
         },
         Instruction::Sub {
             opsize,
-            dest: _,
             source,
+            is_dec: false,
+            ..
         } => {
             gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
 
@@ -2084,11 +2104,7 @@ pub fn gen_test_l(ctx: &mut JitContext, negate: ConditionNegate) {
                 ctx.builder.lt_i32();
             }
         },
-        Instruction::Sub {
-            opsize,
-            dest: _,
-            source,
-        } => {
+        Instruction::Sub { opsize, source, .. } => {
             gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
             gen_get_last_op1(ctx.builder, &ctx.previous_instruction);
             if *opsize == OPSIZE_8 || *opsize == OPSIZE_16 {
@@ -2202,11 +2218,7 @@ pub fn gen_test_le(ctx: &mut JitContext, negate: ConditionNegate) {
                 ctx.builder.le_i32();
             }
         },
-        Instruction::Sub {
-            opsize,
-            dest: _,
-            source,
-        } => {
+        Instruction::Sub { opsize, source, .. } => {
             gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
             gen_get_last_op1(ctx.builder, &ctx.previous_instruction);
             if *opsize == OPSIZE_8 || *opsize == OPSIZE_16 {

src/rust/jit.rs

@@ -270,11 +270,13 @@ pub enum Instruction {
         dest: InstructionOperandDest,
         source: InstructionOperand,
         opsize: i32,
+        is_dec: bool,
     },
     Add {
         dest: InstructionOperandDest,
         source: InstructionOperand,
         opsize: i32,
+        is_inc: bool,
     },
     // Any instruction that sets last_result
     Arithmetic {

src/rust/jit_instructions.rs

@@ -963,6 +963,7 @@ fn gen_add8(ctx: &mut JitContext, dest_operand: &WasmLocal, source_operand: &Loc
         else {
             source_operand.to_instruction_operand(ctx)
         },
+        is_inc: false,
     };
 
     ctx.builder.const_i32(global_pointers::last_op1 as i32);
@@ -994,6 +995,7 @@ fn gen_add32(ctx: &mut JitContext, dest_operand: &WasmLocal, source_operand: &Lo
         else {
             source_operand.to_instruction_operand(ctx)
         },
+        is_inc: false,
     };
 
     codegen::gen_set_last_op1(ctx.builder, &dest_operand);
@@ -1017,6 +1019,7 @@ fn gen_sub8(ctx: &mut JitContext, dest_operand: &WasmLocal, source_operand: &Loc
         else {
             source_operand.to_instruction_operand(ctx)
         },
+        is_dec: false,
     };
 
     ctx.builder.const_i32(global_pointers::last_op1 as i32);
@@ -1048,6 +1051,7 @@ fn gen_sub32(ctx: &mut JitContext, dest_operand: &WasmLocal, source_operand: &Lo
         else {
             source_operand.to_instruction_operand(ctx)
         },
+        is_dec: false,
     };
 
     codegen::gen_set_last_op1(ctx.builder, &dest_operand);
@@ -2330,9 +2334,11 @@ fn gen_inc(ctx: &mut JitContext, dest_operand: &WasmLocal, size: i32) {
     }
     ctx.builder.store_aligned_i32(0);
     codegen::gen_set_last_op_size_and_flags_changed(ctx.builder, size, FLAGS_ALL & !1);
-    ctx.current_instruction = Instruction::Arithmetic {
+    ctx.current_instruction = Instruction::Add {
         opsize: size,
         dest: local_to_instruction_operand(ctx, dest_operand),
+        source: InstructionOperand::Immediate(1),
+        is_inc: true,
     };
 }
 fn gen_inc16(ctx: &mut JitContext, dest_operand: &WasmLocal) {
@@ -2378,9 +2384,11 @@ fn gen_dec(ctx: &mut JitContext, dest_operand: &WasmLocal, size: i32) {
     }
     ctx.builder.store_aligned_i32(0);
     codegen::gen_set_last_op_size_and_flags_changed(ctx.builder, size, FLAGS_ALL & !1 | FLAG_SUB);
-    ctx.current_instruction = Instruction::Arithmetic {
+    ctx.current_instruction = Instruction::Sub {
         opsize: size,
         dest: local_to_instruction_operand(ctx, dest_operand),
+        source: InstructionOperand::Immediate(1),
+        is_dec: true,
     };
 }
 fn gen_dec16(ctx: &mut JitContext, dest_operand: &WasmLocal) {