Add support for ternary short-circuiting (#707)

docs/docs/language/operator-overloading.md

@@ -3,7 +3,7 @@ title: Operator Overloading
 ---
 
 Spice allows overloading operators for [custom struct types](structs.md).
-Currently, this works for the operators `+`, `-`, `*`, `/`, `==`, `!=`, `<<`, `>>`, `+=`, `-=`, `*=`, `/=`,
+Currently, this works for the operators `+`, `-`, `*`, `/`, `==`, `!=`, `<<`, `>>`, `+=`, `-=`, `*=`, `/=`, `[]`,
 `++` (postfix) and `--` (postfix).
 In the future, more operators will be supported for overloading.
 

src/irgenerator/GenExpressions.cpp

@@ -95,19 +95,43 @@ std::any IRGenerator::visitTernaryExpr(const TernaryExprNode *node) {
   // It is a ternary
   // Retrieve the condition value
   llvm::Value *condValue = resolveValue(node->condition);
-
-  // Get the values of true and false
-  llvm::Value *trueValue;
-  llvm::Value *falseValue;
-  if (node->isShortened) {
-    trueValue = condValue;
-    falseValue = resolveValue(node->falseExpr);
+  const LogicalOrExprNode *trueNode = node->isShortened ? node->condition : node->trueExpr;
+  const LogicalOrExprNode *falseNode = node->falseExpr;
+
+  llvm::Value* resultValue;
+  if (trueNode->hasCompileTimeValue() && falseNode->hasCompileTimeValue()) {
+    // If both are constants, we can simply emit a selection instruction
+    llvm::Value *trueValue = resolveValue(trueNode);
+    llvm::Value *falseValue = resolveValue(falseNode);
+    resultValue = builder.CreateSelect(condValue, trueValue, falseValue);
   } else {
-    trueValue = resolveValue(node->trueExpr);
-    falseValue = resolveValue(node->falseExpr);
+    // We have at least one non-constant value, use branching to not perform both sides
+    const std::string codeLoc = node->codeLoc.toPrettyLineAndColumn();
+    llvm::BasicBlock *condTrue = createBlock("cond.true." + codeLoc);
+    llvm::BasicBlock *condFalse = createBlock("cond.false." + codeLoc);
+    llvm::BasicBlock *condExit = createBlock("cond.exit." + codeLoc);
+
+    // Jump from original block to true or false block, depending on condition
+    insertCondJump(condValue, condTrue, condFalse);
+
+    // Fill true block
+    switchToBlock(condTrue);
+    llvm::Value *trueValue = resolveValue(trueNode);
+    insertJump(condExit);
+
+    // Fill false block
+    switchToBlock(condFalse);
+    llvm::Value *falseValue = resolveValue(falseNode);
+    insertJump(condExit);
+
+    // Fill the exit block
+    switchToBlock(condExit);
+    llvm::PHINode* phiInst = builder.CreatePHI(trueValue->getType(), 2, "cond.result");
+    phiInst->addIncoming(trueValue, condTrue);
+    phiInst->addIncoming(falseValue, condFalse);
+    resultValue = phiInst;
   }
 
-  llvm::Value *resultValue = builder.CreateSelect(condValue, trueValue, falseValue);
   return LLVMExprResult{.value = resultValue};
 }
 

src/irgenerator/IRGenerator.cpp

@@ -91,8 +91,8 @@ llvm::Value *IRGenerator::insertInBoundsGEP(llvm::Type *type, llvm::Value *baseP
                                             std::string varName) const {
   assert(basePtr->getType()->isPointerTy());
   assert(!indices.empty());
-  assert(std::ranges::all_of(indices, [](llvm::Value *index) {
-    llvm::Type *indexType = index->getType();
+  assert(std::ranges::all_of(indices, [](const llvm::Value *index) {
+    const llvm::Type *indexType = index->getType();
     return indexType->isIntegerTy(32) || indexType->isIntegerTy(64);
   }));
 
@@ -465,7 +465,7 @@ LLVMExprResult IRGenerator::doAssignment(llvm::Value *lhsAddress, SymbolTableEnt
 
   if (isDecl && rhsSType.is(TY_STRUCT) && rhs.isTemporary()) {
     assert(lhsEntry != nullptr);
-    // Directly set the address to the lhs entry
+    // Directly set the address to the lhs entry (temp stealing)
     llvm::Value *rhsAddress = resolveAddress(rhs);
     lhsEntry->updateAddress(rhsAddress);
     rhs.entry = lhsEntry;

test/test-files/irgenerator/ternary/success-shortened-ternary/ir-code.ll

@@ -25,9 +25,19 @@ define dso_local i32 @main() #1 {
   %result = alloca i32, align 4
   store i32 0, ptr %result, align 4
   %1 = call i1 @_Z2f1v()
-  %2 = call i1 @_Z2f2v()
-  %3 = select i1 %1, i1 %1, i1 %2
-  %4 = zext i1 %3 to i32
+  br i1 %1, label %cond.true.L12C26, label %cond.false.L12C26
+
+cond.true.L12C26:                                 ; preds = %0
+  %2 = call i1 @_Z2f1v()
+  br label %cond.exit.L12C26
+
+cond.false.L12C26:                                ; preds = %0
+  %3 = call i1 @_Z2f2v()
+  br label %cond.exit.L12C26
+
+cond.exit.L12C26:                                 ; preds = %cond.false.L12C26, %cond.true.L12C26
+  %cond.result = phi i1 [ %2, %cond.true.L12C26 ], [ %3, %cond.false.L12C26 ]
+  %4 = zext i1 %cond.result to i32
   %5 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.2, i32 %4)
   %6 = load i32, ptr %result, align 4
   ret i32 %6

test/test-files/irgenerator/ternary/success-ternary-cond-short-circuiting/cout.out

@@ -0,0 +1 @@
+Result: 3

test/test-files/irgenerator/ternary/success-ternary-cond-short-circuiting/ir-code.ll

@@ -0,0 +1,39 @@
+; ModuleID = 'source.spice'
+source_filename = "source.spice"
+
+@printf.str.0 = private unnamed_addr constant [11 x i8] c"Result: %d\00", align 1
+
+define private i1 @_Z10condition1v() {
+  %result = alloca i1, align 1
+  ret i1 false
+}
+
+define private i1 @_Z10condition2v() {
+  %result = alloca i1, align 1
+  ret i1 true
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @main() #0 {
+  %result = alloca i32, align 4
+  store i32 0, ptr %result, align 4
+  %1 = call i1 @_Z10condition1v()
+  br i1 %1, label %land.1.L10C26, label %land.exit.L10C26
+
+land.1.L10C26:                                    ; preds = %0
+  %2 = call i1 @_Z10condition2v()
+  br label %land.exit.L10C26
+
+land.exit.L10C26:                                 ; preds = %land.1.L10C26, %0
+  %land_phi = phi i1 [ %1, %0 ], [ %2, %land.1.L10C26 ]
+  %3 = select i1 %land_phi, i32 2, i32 3
+  %4 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.0, i32 %3)
+  %5 = load i32, ptr %result, align 4
+  ret i32 %5
+}
+
+; Function Attrs: nofree nounwind
+declare noundef i32 @printf(ptr nocapture noundef readonly, ...) #1
+
+attributes #0 = { noinline nounwind optnone uwtable }
+attributes #1 = { nofree nounwind }

test/test-files/irgenerator/ternary/success-ternary-cond-short-circuiting/source.spice

@@ -0,0 +1,11 @@
+f<bool> condition1() {
+    return false;
+}
+
+f<bool> condition2() {
+    return true;
+}
+
+f<int> main() {
+    printf("Result: %d", condition1() && condition2() ? 2: 3);
+}

test/test-files/irgenerator/ternary/success-ternary-short-circuiting/cout.out

@@ -1 +1 @@
-Result: 3
+Result: false

test/test-files/irgenerator/ternary/success-ternary-short-circuiting/ir-code.ll

@@ -1,39 +1,64 @@
 ; ModuleID = 'source.spice'
 source_filename = "source.spice"
 
-@printf.str.0 = private unnamed_addr constant [11 x i8] c"Result: %d\00", align 1
+@anon.string.0 = private unnamed_addr constant [56 x i8] c"Assertion failed: Condition 'false' evaluated to false.\00", align 1
+@anon.string.1 = private unnamed_addr constant [6 x i8] c"false\00", align 1
+@printf.str.0 = private unnamed_addr constant [11 x i8] c"Result: %s\00", align 1
 
-define private i1 @_Z10condition1v() {
+define private i1 @_Z7condFctv() {
   %result = alloca i1, align 1
   ret i1 false
 }
 
-define private i1 @_Z10condition2v() {
-  %result = alloca i1, align 1
-  ret i1 true
+define private ptr @_Z7trueFctv() {
+  %result = alloca ptr, align 8
+  br i1 false, label %assert.exit.L6, label %assert.then.L6, !prof !0
+
+assert.then.L6:                                   ; preds = %0
+  %1 = call i32 (ptr, ...) @printf(ptr @anon.string.0)
+  call void @exit(i32 1)
+  unreachable
+
+assert.exit.L6:                                   ; preds = %0
+  %2 = load ptr, ptr %result, align 8
+  ret ptr %2
+}
+
+; Function Attrs: nofree nounwind
+declare noundef i32 @printf(ptr nocapture noundef readonly, ...) #0
+
+; Function Attrs: cold noreturn nounwind
+declare void @exit(i32) #1
+
+define private ptr @_Z8falseFctv() {
+  %result = alloca ptr, align 8
+  ret ptr @anon.string.1
 }
 
 ; Function Attrs: noinline nounwind optnone uwtable
-define dso_local i32 @main() #0 {
+define dso_local i32 @main() #2 {
   %result = alloca i32, align 4
   store i32 0, ptr %result, align 4
-  %1 = call i1 @_Z10condition1v()
-  br i1 %1, label %land.1.L10C26, label %land.exit.L10C26
+  %1 = call i1 @_Z7condFctv()
+  br i1 %1, label %cond.true.L15C26, label %cond.false.L15C26
 
-land.1.L10C26:                                    ; preds = %0
-  %2 = call i1 @_Z10condition2v()
-  br label %land.exit.L10C26
+cond.true.L15C26:                                 ; preds = %0
+  %2 = call ptr @_Z7trueFctv()
+  br label %cond.exit.L15C26
 
-land.exit.L10C26:                                 ; preds = %land.1.L10C26, %0
-  %land_phi = phi i1 [ %1, %0 ], [ %2, %land.1.L10C26 ]
-  %3 = select i1 %land_phi, i32 2, i32 3
-  %4 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.0, i32 %3)
+cond.false.L15C26:                                ; preds = %0
+  %3 = call ptr @_Z8falseFctv()
+  br label %cond.exit.L15C26
+
+cond.exit.L15C26:                                 ; preds = %cond.false.L15C26, %cond.true.L15C26
+  %cond.result = phi ptr [ %2, %cond.true.L15C26 ], [ %3, %cond.false.L15C26 ]
+  %4 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.0, ptr %cond.result)
   %5 = load i32, ptr %result, align 4
   ret i32 %5
 }
 
-; Function Attrs: nofree nounwind
-declare noundef i32 @printf(ptr nocapture noundef readonly, ...) #1
+attributes #0 = { nofree nounwind }
+attributes #1 = { cold noreturn nounwind }
+attributes #2 = { noinline nounwind optnone uwtable }
 
-attributes #0 = { noinline nounwind optnone uwtable }
-attributes #1 = { nofree nounwind }
+!0 = !{!"branch_weights", i32 2000, i32 1}

test/test-files/irgenerator/ternary/success-ternary-short-circuiting/source.spice

@@ -1,11 +1,16 @@
-f<bool> condition1() {
+f<bool> condFct() {
     return false;
 }
 
-f<bool> condition2() {
-    return true;
+f<string> trueFct() {
+    assert false; // Should not be called
+    return "true";
+}
+
+f<string> falseFct() {
+    return "false";
 }
 
 f<int> main() {
-    printf("Result: %d", condition1() && condition2() ? 2: 3);
+    printf("Result: %s", condFct() ? trueFct() : falseFct());
 }

test/test-files/irgenerator/ternary/success-ternary-stmt/ir-code.ll

@@ -16,13 +16,22 @@ define dso_local i32 @main() #0 {
   store i32 0, ptr %result, align 4
   store i1 true, ptr %condition, align 1
   %1 = load i1, ptr %condition, align 1
+  br i1 %1, label %cond.true.L7C13, label %cond.false.L7C13
+
+cond.true.L7C13:                                  ; preds = %0
   %2 = call i32 @_Z3getv()
-  %3 = select i1 %1, i32 %2, i32 24
-  store i32 %3, ptr %r, align 4
-  %4 = load i32, ptr %r, align 4
-  %5 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.0, i32 %4)
-  %6 = load i32, ptr %result, align 4
-  ret i32 %6
+  br label %cond.exit.L7C13
+
+cond.false.L7C13:                                 ; preds = %0
+  br label %cond.exit.L7C13
+
+cond.exit.L7C13:                                  ; preds = %cond.false.L7C13, %cond.true.L7C13
+  %cond.result = phi i32 [ %2, %cond.true.L7C13 ], [ 24, %cond.false.L7C13 ]
+  store i32 %cond.result, ptr %r, align 4
+  %3 = load i32, ptr %r, align 4
+  %4 = call i32 (ptr, ...) @printf(ptr noundef @printf.str.0, i32 %3)
+  %5 = load i32, ptr %result, align 4
+  ret i32 %5
 }
 
 ; Function Attrs: nofree nounwind