Misc peephole opts.

src/backend/pass/emit/x86/x86_emit.cpp

@@ -26,15 +26,14 @@ namespace rat {
 
 	MachineInstr& X86LowerPass::put(
 			X86Op op, List<MachineOperand> defs, List<MachineOperand> uses, I64 imm, I64 imm2) {
-		MachineInstr m;
+		MachineInstr& m = mb->insts.emplace_back();
 		m.op = (MachineOpcode)op;
 		m.regClass = x86OpInfo(op).cls;
 		m.defs = std::move(defs);
 		m.uses = std::move(uses);
 		m.imm = imm;
 		m.imm2 = imm2;
-		mb->insts.push_back(std::move(m));
-		return mb->insts.back();
+		return m;
 	}
 
 	// data movement

src/backend/pass/emit/x86/x86_layout.cpp

@@ -54,6 +54,11 @@ namespace rat {
 
 		B32 isBlockRef(const MachineOperand& o) { return o.kind == MachineOperand::Kind::Block; }
 
+		B32 isBranch(const MachineInstr& in) {
+			X86Op op = (X86Op)in.op;
+			return op == X86Op::Jmp || op == X86Op::Br || op == X86Op::SwitchJump;
+		}
+
 		I32 resolveJump(const MachineFunc& mf, I32 id) {
 			U32 hops = 0;
 			while(hops++ < 16) {
@@ -80,14 +85,15 @@ namespace rat {
 				if(b.id < 0)
 					continue;
 				for(MachineInstr& in : b.insts)
-					for(MachineOperand& u : in.uses)
-						if(isBlockRef(u)) {
-							I32 r = resolveJump(mf, u.block);
-							if(r != u.block) {
-								u.block = r;
-								++changed;
+					if(isBranch(in))
+						for(MachineOperand& u : in.uses)
+							if(isBlockRef(u)) {
+								I32 r = resolveJump(mf, u.block);
+								if(r != u.block) {
+									u.block = r;
+									++changed;
+								}
 							}
-						}
 			}
 			return changed;
 		}
@@ -124,9 +130,10 @@ namespace rat {
 					continue;
 				blockAt[(U32)b.id] = i;
 				for(const MachineInstr& in : b.insts)
-					for(const MachineOperand& u : in.uses)
-						if(isBlockRef(u))
-							succ[(U32)b.id].push_back(u.block);
+					if(isBranch(in))
+						for(const MachineOperand& u : in.uses)
+							if(isBlockRef(u))
+								succ[(U32)b.id].push_back(u.block);
 			}
 
 			I32 entry = -1;

src/backend/pass/emit/x86/x86_layout.h

@@ -15,12 +15,14 @@
 namespace rat {
 	struct MachineBlock;
 	struct MachineFunc;
+	struct MachineInstr;
 	struct MachineOperand;
 
 	namespace detail {
 		B32 isPureTestBlock(const MachineBlock& b);
 		U32 duplicateTestBlocks(MachineFunc& mf);
 		B32 isBlockRef(const MachineOperand& o);
+		B32 isBranch(const MachineInstr& in);
 		I32 resolveJump(const MachineFunc& mf, I32 id);
 		U32 forwardJumpChains(MachineFunc& mf);
 		List<B32> reachableFrom(const List<List<I32>>& succ, I32 entry);

src/backend/pass/emit/x86/x86_lower.cpp

@@ -504,6 +504,7 @@ namespace rat {
 			MachineBlock& block = out->blocks[b];
 			block.id = b;
 			block.loopDepth = sched->block(b).loopDepth;
+			block.insts.reserve(sched->block(b).nodes.size() * 2 + 4);
 			mb = █
 			if(i == 0)
 				emitPrologue();