From 200bb6453ce8dcae8b30bf4fb2fcc2cbbf02e00e Mon Sep 17 00:00:00 2001
From: Brian Fiete <bfiete@gmail.com>
Date: Wed, 1 Mar 2023 05:41:20 -0500
Subject: [PATCH] Pointer subtraction using stride instead of size

---
 IDEHelper/Compiler/BfExprEvaluator.cpp |  2 +-
 IDEHelper/Tests/src/Loops.bf           | 15 +++++++++++++++
 IDEHelper/Tests/src/Structs.bf         | 14 ++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/IDEHelper/Compiler/BfExprEvaluator.cpp b/IDEHelper/Compiler/BfExprEvaluator.cpp
index 3a27484b..b122b8f2 100644
--- a/IDEHelper/Compiler/BfExprEvaluator.cpp
+++ b/IDEHelper/Compiler/BfExprEvaluator.cpp
@@ -24256,7 +24256,7 @@ void BfExprEvaluator::PerformBinaryOperation(BfAstNode* leftExpression, BfAstNod
 				convLeftValue = mModule->CastToValue(leftExpression, leftValue, intPtrType, (BfCastFlags)(BfCastFlags_Explicit | BfCastFlags_FromCompiler));
 				convRightValue = mModule->CastToValue(rightExpression, rightValue, intPtrType, (BfCastFlags)(BfCastFlags_Explicit | BfCastFlags_FromCompiler));
 				BfIRValue diffValue = mModule->mBfIRBuilder->CreateSub(convLeftValue, convRightValue);
-				diffValue = mModule->mBfIRBuilder->CreateDiv(diffValue, mModule->GetConstValue(resultPointerType->mElementType->mSize, intPtrType), true);
+				diffValue = mModule->mBfIRBuilder->CreateDiv(diffValue, mModule->GetConstValue(resultPointerType->mElementType->GetStride(), intPtrType), true);
 				mResult = BfTypedValue(diffValue, intPtrType);
 			}
 			return;
diff --git a/IDEHelper/Tests/src/Loops.bf b/IDEHelper/Tests/src/Loops.bf
index 9909ec56..3ed41260 100644
--- a/IDEHelper/Tests/src/Loops.bf
+++ b/IDEHelper/Tests/src/Loops.bf
@@ -134,9 +134,24 @@ namespace Tests
 			Test.Assert(!(1..<3).Contains(1..<4));
 
 			List<int> iList = scope .() { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 };
+			int itrCount = 0;
 			total = 0;
 			for (int i in iList[...])
+			{
+				itrCount++;
 				total += i;
+			}
+			Test.Assert(itrCount == 10);
+			Test.Assert(total == 10+20+30+40+50+60+70+80+90+100);
+
+			total = 0;
+			itrCount = 0;
+			for (int i in iList[...].Reversed)
+			{
+				itrCount++;
+				total += i;
+			}
+			Test.Assert(itrCount == 10);
 			Test.Assert(total == 10+20+30+40+50+60+70+80+90+100);
 
 			total = 0;
diff --git a/IDEHelper/Tests/src/Structs.bf b/IDEHelper/Tests/src/Structs.bf
index a0518aa0..d5473c8b 100644
--- a/IDEHelper/Tests/src/Structs.bf
+++ b/IDEHelper/Tests/src/Structs.bf
@@ -189,6 +189,20 @@ namespace Tests
 
 			StructN sn = GetStructN();
 			Test.Assert(sn.mA == 123);
+
+			List<StructD> list = scope .();
+			for (int i < 10)
+				list.Add(default);
+			var ptr0 = &list[0];
+			var ptr9 = &list[9];
+
+			int count = ptr9 - ptr0;
+			Test.Assert(count == 9);
+
+			var ptr9B = ptr0 + 9;
+			count = ptr9B - ptr0;
+			Test.Assert(ptr9 == ptr9B);
+			Test.Assert(count == 9);
 		}
 
 		[Align(16)]