From 5b50389340135d50488971df8a6705b086883b59 Mon Sep 17 00:00:00 2001
From: drmortalwombat <90205530+drmortalwombat@users.noreply.github.com>
Date: Sun, 21 Jul 2024 21:43:59 +0200
Subject: [PATCH] Optimize 32bit shifts

---
 autotest/bitshifttest.c         |  4 ++++
 oscar64/InterCode.cpp           |  2 +-
 oscar64/NativeCodeGenerator.cpp | 42 +++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/autotest/bitshifttest.c b/autotest/bitshifttest.c
index 63d914a..f54ea20 100644
--- a/autotest/bitshifttest.c
+++ b/autotest/bitshifttest.c
@@ -373,21 +373,25 @@ int main(void)
 	shr16n(0xfedc, 0xfedc);
 
 	shl32b(0x00000000UL, 0x00000000L);
+	shl32b(0x00000001UL, 0x00000001L);
 	shl32b(0xffffffffUL, 0xffffffffL);
 	shl32b(0x12345678UL, 0x12345678L);
 	shl32b(0xfedcba98UL, 0xfedcba98L);
 
 	shr32b(0x00000000UL, 0x00000000L);
+	shr32b(0x00000001UL, 0x00000001L);
 	shr32b(0xffffffffUL, 0xffffffffL);
 	shr32b(0x12345678UL, 0x12345678L);
 	shr32b(0xfedcba98UL, 0xfedcba98L);
 
 	shl32n(0x00000000UL, 0x00000000L);
+	shl32n(0x00000001UL, 0x00000001L);
 	shl32n(0xffffffffUL, 0xffffffffL);
 	shl32n(0x12345678UL, 0x12345678L);
 	shl32n(0xfedcba98UL, 0xfedcba98L);
 
 	shr32n(0x00000000UL, 0x00000000L);
+	shr32n(0x00000001UL, 0x00000001L);
 	shr32n(0xffffffffUL, 0xffffffffL);
 	shr32n(0x12345678UL, 0x12345678L);
 	shr32n(0xfedcba98UL, 0xfedcba98L);
diff --git a/oscar64/InterCode.cpp b/oscar64/InterCode.cpp
index 9c19616..c83e6f5 100644
--- a/oscar64/InterCode.cpp
+++ b/oscar64/InterCode.cpp
@@ -15247,7 +15247,7 @@ void InterCodeBasicBlock::EliminateDoubleLoopCounter(void)
 			{
 				if (mEntryBlocks[i] != mLoopPrefix)
 				{
-					if (!mEntryBlocks[i]->CollectLoopBody(this, body))
+					if (!mEntryBlocks[i]->CollectLoopBodyRecursive(this, body))
 						innerLoop = false;
 				}
 			}
diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index b93f323..6c1d4db 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -9823,6 +9823,39 @@ NativeCodeBasicBlock* NativeCodeBasicBlock::BinaryOperator(InterCodeProcedure* p
 					return eblock;
 				}
 			}
+			else if (ins->mSrc[1].mTemp < 0 && ins->mSrc[1].mIntConst == 1)
+			{
+				NativeCodeBasicBlock* lblock = nproc->AllocateBlock();
+				NativeCodeBasicBlock* hblock = nproc->AllocateBlock();
+				NativeCodeBasicBlock* eblock = nproc->AllocateBlock();
+
+				mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ZERO_PAGE, BC_REG_TMP + proc->mTempOffset[ins->mSrc[0].mTemp]));
+				mIns.Push(NativeCodeInstruction(ins, ASMIT_AND, ASMIM_IMMEDIATE, 0x1f));
+				mIns.Push(NativeCodeInstruction(ins, ASMIT_TAX, ASMIM_IMPLIED));
+				mIns.Push(NativeCodeInstruction(ins, ASMIT_AND, ASMIM_IMMEDIATE, 0x10));
+				this->Close(ins, lblock, hblock, ASMIT_BEQ);
+
+				NativeCodeGenerator::Runtime& frt(nproc->mGenerator->ResolveRuntime(Ident::Unique("bitshift")));
+
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 2));
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 3));
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ABSOLUTE_X, frt.mOffset + 8, frt.mLinkerObject));
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg));
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ABSOLUTE_X, frt.mOffset, frt.mLinkerObject));
+				lblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 1));
+				lblock->Close(ins, eblock, nullptr, ASMIT_JMP);
+
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_IMMEDIATE, 0));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 0));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 1));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ABSOLUTE_X, frt.mOffset - 16, frt.mLinkerObject));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 2));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_LDA, ASMIM_ABSOLUTE_X, frt.mOffset - 8, frt.mLinkerObject));
+				hblock->mIns.Push(NativeCodeInstruction(ins, ASMIT_STA, ASMIM_ZERO_PAGE, treg + 3));
+				hblock->Close(ins, eblock, nullptr, ASMIT_JMP);
+
+				return eblock;
+			}
 			else
 			{
 				NativeCodeBasicBlock* lblock = nproc->AllocateBlock();
@@ -44931,6 +44964,15 @@ bool NativeCodeBasicBlock::PeepHoleOptimizerIterate3(int i, int pass)
 		mIns[i + 2].mLive |= LIVE_CPU_REG_Y;
 		return true;
 	}
+	else if (
+		mIns[i + 0].mType == ASMIT_STA &&
+		mIns[i + 1].mType == ASMIT_STA &&
+		mIns[i + 2].IsShift() && mIns[i + 2].SameEffectiveAddress(mIns[i + 0]) && !(mIns[i + 2].mLive & (LIVE_CPU_REG_A | LIVE_MEM)))
+	{
+		mIns[i + 0].mType = ASMIT_NOP; mIns[i + 0].mMode = ASMIM_IMPLIED;
+		mIns[i + 2].mMode = ASMIM_IMPLIED;
+		return true;
+	}
 
 	if (
 		mIns[i + 0].mType == ASMIT_LDY && mIns[i + 0].mMode == ASMIM_IMMEDIATE && mIns[i + 0].mAddress <= 1 &&