Generate code for for loops

[kaleidoscope-hs.git] / Main.hs

diff --git a/Main.hs b/Main.hs
index 749f77188172479f341a8018650af7549c2d0c02..97407fee2fbf6ef7907f3f45a934e737fa29d593 100644 (file)
--- a/Main.hs
+++ b/Main.hs
@@ -163,3 +163,39 @@ buildExpr (If cond thenE elseE) = mdo
 
   mergeB <- block `named` "ifcont"
   phi [(thenOp, thenB), (elseOp, elseB)]
+
+buildExpr (For name init cond mStep body) = mdo
+  preheaderB <- block `named` "preheader"
+
+  initV <- buildExpr init `named` "init"
+  
+  -- build the condition expression with 'i' in the bindings
+  initCondV <- withReaderT (Map.insert name initV) $
+                (buildExpr cond >>= fcmp ONE zero) `named` "initcond"
+
+  -- skip the loop if we don't meet the condition with the init
+  condBr initCondV loopB afterB
+
+  loopB <- block `named` "loop"
+  i <- phi [(initV, preheaderB), (nextVar, loopB)] `named` "i"
+
+  -- build the body expression with 'i' in the bindings
+  withReaderT (Map.insert name i) $ buildExpr body `named` "body"
+
+  -- default to 1 if there's no step defined
+  stepV <- case mStep of
+    Just step -> buildExpr step
+    Nothing -> return $ ConstantOperand (Float (Double 1))
+
+  nextVar <- fadd i stepV `named` "nextvar"
+
+  let zero = ConstantOperand (Float (Double 0))
+  -- again we need 'i' in the bindings
+  condV <- withReaderT (Map.insert name i) $
+            (buildExpr cond >>= fcmp ONE zero) `named` "cond"
+  condBr condV loopB afterB
+
+  afterB <- block `named` "after"
+  -- since a for loop doesn't really have a value, return 0
+  return $ ConstantOperand (Float (Double 0))
+