From b62183adcb137bee56158c817bc7f11fb2517243 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Thu, 30 Dec 2021 02:00:36 +0100
Subject: [PATCH] slightly optimized binexpr evaluation for ==/!= in some cases

---
 .../src/prog8/optimizer/BinExprSplitter.kt    | 11 ++++++++++-
 compiler/src/prog8/compiler/Compiler.kt       |  6 +++++-
 examples/test.p8                              | 19 ++++++++++++++-----
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt b/codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt
index 84d9a2f27..cbf5594b2 100644
--- a/codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt
+++ b/codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt
@@ -45,7 +45,7 @@ X =      BinExpr                                    X   =   LeftExpr
 
 
  */
-            if(binExpr.operator in AugmentAssignmentOperators && isSimpleTarget(assignment.target)) {
+            if(binExpr.operator in AugmentAssignmentOperators + listOf("==", "!=") && isSimpleTarget(assignment.target)) {
                 if(assignment.target isSameAs binExpr.right)
                     return noModifications
                 if(assignment.target isSameAs binExpr.left) {
@@ -73,6 +73,15 @@ X =      BinExpr                                    X   =   LeftExpr
 //                    )
                 }
 
+                if(binExpr.operator == "==" || binExpr.operator == "!=") {
+                    // don't split if the operand(s) don't fit the type of the resulting variable
+                    val targetDt = assignment.target.inferType(program)
+                    val leftDt = binExpr.left.inferType(program)
+                    val rightDt = binExpr.right.inferType(program)
+                    if(leftDt isNotAssignableTo targetDt || rightDt isNotAssignableTo targetDt)
+                        return noModifications
+                }
+
                 if(binExpr.right.isSimple) {
                     val firstAssign = Assignment(assignment.target.copy(), binExpr.left, binExpr.left.position)
                     val targetExpr = assignment.target.toExpression()
diff --git a/compiler/src/prog8/compiler/Compiler.kt b/compiler/src/prog8/compiler/Compiler.kt
index f16a77079..45430e3cf 100644
--- a/compiler/src/prog8/compiler/Compiler.kt
+++ b/compiler/src/prog8/compiler/Compiler.kt
@@ -66,7 +66,10 @@ fun compileProgram(args: CompilerArguments): CompilationResult {
             program = programresult
             importedFiles = imported
             processAst(program, args.errors, compilationOptions)
-            if (compilationOptions.optimize)
+            if (compilationOptions.optimize) {
+//                println("*********** AST RIGHT BEFORE OPTIMIZING *************")
+//                printProgram(program)
+
                 optimizeAst(
                     program,
                     compilationOptions,
@@ -74,6 +77,7 @@ fun compileProgram(args: CompilerArguments): CompilationResult {
                     BuiltinFunctionsFacade(BuiltinFunctions),
                     compTarget
                 )
+            }
             postprocessAst(program, args.errors, compilationOptions)
 
 //            println("*********** AST BEFORE ASSEMBLYGEN *************")
diff --git a/examples/test.p8 b/examples/test.p8
index fa34c500e..eaf16d5ce 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -5,12 +5,21 @@ main {
     sub start() {
         ubyte @shared xx
         ubyte @shared yy
+        ubyte camg
 
+        ubyte @shared interlaced = (camg & $04) != 0
+
+        yy = xx
+        yy = yy==7
+
+        yy++
         yy = xx==7
-        if xx==99 {
-            xx++
-            yy++
-        }
-        txt.nl()
+        yy++
+
+;        if xx==99 {
+;            xx++
+;            yy++
+;        }
+;        txt.nl()
     }
 }