Added fannkuch example.

resources/examples/fannkuch-redux.c3

@@ -0,0 +1,81 @@
+module fannkuch;
+import std::mem;
+
+macro int max(int a, int b)
+{
+    return a > b ? a : b;
+}
+
+func int fannkuchredux(int n)
+{
+    int* perm = mem::alloc($sizeof(int), n);
+    int* perm1 = mem::alloc($sizeof(int), n);
+    int* count = mem::alloc($sizeof(int), n);
+    int maxFlipsCount;
+    int permCount;
+    int checksum;
+
+    for (int i = 0; i < n; i++) perm1[i] = i;
+
+    int r = n;
+
+    while (1)
+    {
+        for (; r != 1; r--) count[r - 1] = r;
+
+        for (int i = 0; i < n; i++) perm[i] = perm1[i];
+
+        int flipsCount = 0;
+        int k;
+
+        while (!((k = perm[0]) == 0))
+        {
+            int k2 = (k + 1) >> 1;
+            for (int i = 0; i < k2; i++)
+            {
+                int temp = perm[i];
+                perm[i] = perm[k - i];
+                perm[k - i] = temp;
+            }
+            flipsCount++;
+        }
+
+        maxFlipsCount = @max(maxFlipsCount, flipsCount);
+        checksum += permCount % 2 == 0 ? flipsCount : -flipsCount;
+
+        /* Use incremental change to generate another permutation */
+        while (1)
+        {
+            if (r == n)
+            {
+                printf("%d\n", checksum);
+                return maxFlipsCount;
+            }
+
+            int perm0 = perm1[0];
+            int i = 0;
+            while (i < r)
+            {
+                int j = i + 1;
+                perm1[i] = perm1[j];
+                i = j;
+            }
+            perm1[r] = perm0;
+            count[r] = count[r] - 1;
+            if (count[r] > 0) break;
+            r++;
+        }
+        permCount++;
+    }
+    return 0;
+}
+
+extern func int atoi(char *s);
+extern func int printf(char *s, ...);
+
+func int main(int argc, char** argv)
+{
+    int n = argc > 1 ? atoi(argv[1]) : 7;
+    printf("Pfannkuchen(%d) = %d\n", n, fannkuchredux(n));
+    return 0;
+}

src/compiler/llvm_codegen_stmt.c

@@ -572,17 +572,41 @@ void gencontext_emit_while_stmt(GenContext *context, Ast *ast)
 	// First, emit all inits.
 	LLVMBasicBlockRef exit_block = llvm_basic_block_new(context, "while.exit");
 	LLVMBasicBlockRef begin_block = llvm_basic_block_new(context, "while.begin");
-	LLVMBasicBlockRef body_block = ast->while_stmt.body->compound_stmt.stmts ? llvm_basic_block_new(context,
-	                                                                                                  "while.body") : NULL;
+	LLVMBasicBlockRef body_block = ast->while_stmt.body->compound_stmt.stmts ? llvm_basic_block_new(context,																										"while.body") : NULL;
 
 	ast->while_stmt.continue_block = begin_block;
 	ast->while_stmt.break_block = exit_block;
 
+	Expr *cond = ast->while_stmt.cond;
+
+	bool is_infinite_loop = false;
+
+	// Is this while (false) or while (true)
+	if (cond->expr_kind == EXPR_COND && vec_size(cond->cond_expr) == 1)
+	{
+		Expr *expr = cond->cond_expr[0];
+		if (expr->expr_kind == EXPR_CONST && expr->const_expr.const_kind == CONST_BOOL)
+		{
+			is_infinite_loop = expr->const_expr.b;
+			// This is a NOP
+			if (!is_infinite_loop) return;
+			assert(body_block);
+		}
+	}
+
+	DeferList defers = { 0, 0 };
+
 	// Emit cond
 	llvm_emit_br(context, begin_block);
+
+	if (is_infinite_loop)
+	{
+		body_block = begin_block;
+		goto EMIT_BODY;
+	}
+
 	llvm_emit_block(context, begin_block);
-	DeferList defers = { 0, 0 };
-	Expr *cond = ast->while_stmt.cond;
+
 	if (cond->expr_kind == EXPR_SCOPED_EXPR)
 	{
 		defers = cond->expr_scope.defers;
@@ -606,6 +630,7 @@ void gencontext_emit_while_stmt(GenContext *context, Ast *ast)
 		llvm_emit_cond_br(context, &be_value, begin_block, exit_block);
 	}
 
+EMIT_BODY:
 	if (body_block)
 	{
 		llvm_emit_block(context, body_block);

test/test_suite/statements/foreach_custom.c3t

@@ -132,14 +132,8 @@ for.body:
   br label %while.begin
 
 while.begin:
-  br i1 true, label %while.body, label %while.exit
-
-while.body:
   br label %for.exit
 
-while.exit:
-  br label %for.cond
-
 for.exit:
   ret void
 }

test/test_suite/statements/foreach_custom_macro.c3t

@@ -39,7 +39,6 @@ extern func int printf(char *fmt, ...);
 // #expect: foo.ll
 
 define void @main()
-entry:
   %i = alloca [3 x i32], align 4
   %x = alloca %Foo, align 8
   %f = alloca i32, align 4
@@ -69,13 +68,13 @@ entry:
   call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %8, i8* align 8 %9, i32 16, i1 false)
   br label %expr_block.exit
 
-expr_block.exit:
+expr_block.exit:                                  ; preds = %entry
   %10 = bitcast %FooIterator* %.iterator to i8*
   %11 = bitcast %FooIterator* %blockret to i8*
   call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %10, i8* align 8 %11, i32 16, i1 false)
   br label %for.cond
 
-for.cond:
+for.cond:                                         ; preds = %expr_block.exit
   store %FooIterator* %.iterator, %FooIterator** %it, align 8
   store i32* %f, i32** %value, align 8
   %12 = load %FooIterator*, %FooIterator** %it, align 8
@@ -90,11 +89,11 @@ for.cond:
   %eq = icmp eq i64 %14, %19
   br i1 %eq, label %if.then, label %if.exit
 
-if.then:
+if.then:                                          ; preds = %for.cond
   store i8 0, i8* %blockret2, align 1
   br label %expr_block.exit3
 
-if.exit:
+if.exit:                                          ; preds = %for.cond
   %20 = load i32*, i32** %value, align 8
   %21 = load %FooIterator*, %FooIterator** %it, align 8
   %22 = getelementptr inbounds %FooIterator, %FooIterator* %21, i32 0, i32 1
@@ -113,25 +112,19 @@ if.exit:
   store i8 1, i8* %blockret2, align 1
   br label %expr_block.exit3
 
-expr_block.exit3:
+expr_block.exit3:                                 ; preds = %if.exit, %if.then
   %29 = load i8, i8* %blockret2, align 1
   %30 = trunc i8 %29 to i1
   br i1 %30, label %for.body, label %for.exit
 
-for.body:
+for.body:                                         ; preds = %expr_block.exit3
   %31 = load i32, i32* %f, align 4
   %32 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %31)
   br label %while.begin
 
-while.begin:
-  br i1 true, label %while.body, label %while.exit
-
-while.body:
+while.begin:                                      ; preds = %for.body
   br label %for.exit
 
-while.exit:
-  br label %for.cond
-
-for.exit:
+for.exit:                                         ; preds = %while.begin, %expr_block.exit3
   ret void
 }