From 57123e8f9e17cf96995a644fdebaf6abbce016c0 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 19 Aug 2023 22:36:35 -0700
Subject: [PATCH] irjit: Reserve some arrays that churn.

Improves IR compile time by around 20-30%.
---
 Core/MIPS/IR/IRInst.h           | 3 +++
 Core/MIPS/IR/IRJit.cpp          | 1 +
 Core/MIPS/IR/IRPassSimplify.cpp | 9 +++++++++
 3 files changed, 13 insertions(+)

diff --git a/Core/MIPS/IR/IRInst.h b/Core/MIPS/IR/IRInst.h
index 2b192a6890..f9131152af 100644
--- a/Core/MIPS/IR/IRInst.h
+++ b/Core/MIPS/IR/IRInst.h
@@ -375,6 +375,9 @@ public:
 	int AddConstant(u32 value);
 	int AddConstantFloat(float value);
 
+	void Reserve(size_t s) {
+		insts_.reserve(s);
+	}
 	void Clear() {
 		insts_.clear();
 	}
diff --git a/Core/MIPS/IR/IRJit.cpp b/Core/MIPS/IR/IRJit.cpp
index 44621c2dd5..e64dcf3ecd 100644
--- a/Core/MIPS/IR/IRJit.cpp
+++ b/Core/MIPS/IR/IRJit.cpp
@@ -168,6 +168,7 @@ void IRJit::CompileFunction(u32 start_address, u32 length) {
 	// We may go up and down from branches, so track all block starts done here.
 	std::set<u32> doneAddresses;
 	std::vector<u32> pendingAddresses;
+	pendingAddresses.reserve(16);
 	pendingAddresses.push_back(start_address);
 	while (!pendingAddresses.empty()) {
 		u32 em_address = pendingAddresses.back();
diff --git a/Core/MIPS/IR/IRPassSimplify.cpp b/Core/MIPS/IR/IRPassSimplify.cpp
index 3c020edd4f..8f9485c11d 100644
--- a/Core/MIPS/IR/IRPassSimplify.cpp
+++ b/Core/MIPS/IR/IRPassSimplify.cpp
@@ -86,6 +86,8 @@ IROp ShiftToShiftImm(IROp op) {
 }
 
 bool IRApplyPasses(const IRPassFunc *passes, size_t c, const IRWriter &in, IRWriter &out, const IROptions &opts) {
+	out.Reserve(in.GetInstructions().size());
+
 	if (c == 1) {
 		return passes[0](in, out, opts);
 	}
@@ -95,6 +97,7 @@ bool IRApplyPasses(const IRPassFunc *passes, size_t c, const IRWriter &in, IRWri
 	IRWriter temp[2];
 	const IRWriter *nextIn = &in;
 	IRWriter *nextOut = &temp[1];
+	temp[1].Reserve(nextIn->GetInstructions().size());
 	for (size_t i = 0; i < c - 1; ++i) {
 		if (passes[i](*nextIn, *nextOut, opts)) {
 			logBlocks = true;
@@ -102,8 +105,12 @@ bool IRApplyPasses(const IRPassFunc *passes, size_t c, const IRWriter &in, IRWri
 
 		temp[0] = std::move(temp[1]);
 		nextIn = &temp[0];
+
+		temp[1].Clear();
+		temp[1].Reserve(nextIn->GetInstructions().size());
 	}
 
+	out.Reserve(nextIn->GetInstructions().size());
 	if (passes[c - 1](*nextIn, out, opts)) {
 		logBlocks = true;
 	}
@@ -947,6 +954,8 @@ bool PurgeTemps(const IRWriter &in, IRWriter &out, const IROptions &opts) {
 		int8_t fplen = 0;
 	};
 	std::vector<Check> checks;
+	checks.reserve(insts.size() / 2);
+
 	// This tracks the last index at which each reg was modified.
 	int lastWrittenTo[256];
 	int lastReadFrom[256];