Add BLKLOOPINIT error code, and describe --unroll-count.

Changes

@@ -3,6 +3,10 @@ Revision history for Verilator
 The contributors that suggested a given feature are shown in [].  [by ...]
 indicates the contributor was also the author of the fix; Thanks!
 
+* Verilator 3.711 2009/**
+
+**** Add BLKLOOPINIT error code, and describe --unroll-count.  [Jeff Winston]
+
 * Verilator 3.711 2009/06/23
 
 **** Support decimal constants of arbitrary widths. [Mark Marshall]

bin/verilator

@@ -1617,17 +1617,9 @@ All specify blocks and timing checks are ignored.
 
 =head2 Array Initialization
 
-When initializing an array, you need to use non-delayed assignments.  This
+When initializing a large array, you need to use non-delayed assignments.
-is done in the interest of speed; if delayed assignments were used, the
+Verilator will tell you when this needs to be fixed; see the BLKLOOPINIT
-simulator would have to copy large arrays every cycle.  (In smaller loops,
+error for more information.
-loop unrolling allows the delayed assignment to work, though it's a bit
-slower than a non-delayed assignment.)  Here's an example
-
-	always @ (posedge clk)
-            if (~reset_l) begin
-                for (i=0; i<`ARRAY_SIZE; i++) begin
-		    array[i] = 0;	 // Non-delayed for verilator
-                end
 
 =head2 Array Out of Bounds
 
@@ -1795,6 +1787,24 @@ inside a public task.
 Ignoring this warning may make Verilator simulations differ from other
 simulators.
 
+=item BLKLOOPINIT
+
+This indicates that the initialization of an array needs to use non-delayed
+assignments.  This is done in the interest of speed; if delayed assignments
+were used, the simulator would have to copy large arrays every cycle.  (In
+smaller loops, loop unrolling allows the delayed assignment to work, though
+it's a bit slower than a non-delayed assignment.)  Here's an example
+
+	always @ (posedge clk)
+            if (~reset_l) begin
+                for (i=0; i<`ARRAY_SIZE; i++) begin
+		    array[i] = 0;	 // Non-delayed for verilator
+                end
+
+This message is only seen on large or complicated loops because Verilator
+generally unrolls small loops.  You may want to try increasing
+--unroll-count which will raise the small loop bar to avoid this error.
+
 =item CASEINCOMPLETE
 
 Warns that inside a case statement there is a stimulus pattern for which

src/V3Delayed.cpp

@@ -335,7 +335,7 @@ private:
 		&& nodep->lhsp()->castSel()->fromp()->castArraySel())) {
 	    AstNode* lhsp = nodep->lhsp()->unlinkFrBack();
 	    AstNode* newlhsp = createDlyArray(nodep, lhsp);
-	    if (m_inLoop) nodep->v3error("Unsupported: Delayed assignment to array inside for loops (non-delayed is ok - see docs)");
+	    if (m_inLoop) nodep->v3warn(BLKLOOPINIT,"Unsupported: Delayed assignment to array inside for loops (non-delayed is ok - see docs)");
 	    if (newlhsp) {
 		nodep->lhsp(newlhsp);
 	    } else {

src/V3Error.h

@@ -47,6 +47,7 @@ public:
 	// Error codes:
 	MULTITOP,	// Error: Multiple top level modules
 	TASKNSVAR,	// Error: Task I/O not simple
+	BLKLOOPINIT,	// Error: Delayed assignment to array inside for loops
 	// Warning codes:
 	FIRST_WARN,	// Just a code so the program knows where to start warnings
 	//
@@ -88,7 +89,7 @@ public:
 	    // Boolean
 	    " I_COVERAGE", " I_TRACING",
 	    // Errors
-	    "MULTITOP", "TASKNSVAR",
+	    "MULTITOP", "TASKNSVAR", "BLKLOOPINIT",
 	    // Warnings
 	    " FIRST_WARN",
 	    "BLKANDNBLK",