ModuleInst.place() to check both RAMB36/RAMB18 sites for overlap

src/com/xilinx/rapidwright/design/ModuleInst.java

@@ -326,7 +326,37 @@ public boolean place(Site newAnchorSite, boolean skipIncompatible, boolean allow
             Tile newTile = module.getCorrespondingTile(templateSite.getTile(), newAnchorSite.getTile());
             Site newSite = templateSite.getCorrespondingSite(inst.getSiteTypeEnum(), newTile);
 
-            SiteInst existingSiteInst = allowOverlap ? null : design.getSiteInstFromSite(newSite);
+            SiteInst existingSiteInst;
+            if (allowOverlap) {
+                existingSiteInst = null;
+            } else {
+                existingSiteInst = design.getSiteInstFromSite(newSite);
+                if (existingSiteInst == null) {
+                    SiteTypeEnum siteType = newSite.getSiteTypeEnum();
+                    if (siteType == SiteTypeEnum.RAMBFIFO36) { // UltraScale+
+                        // Check that both RAMB18s are free
+                        for (Site alternateSite : newTile.getSites()) {
+                            if (alternateSite.getSiteTypeEnum() != SiteTypeEnum.RAMBFIFO18 &&
+                                alternateSite.getSiteTypeEnum() != SiteTypeEnum.RAMB181) {
+                                continue;
+                            }
+                            existingSiteInst = design.getSiteInstFromSite(alternateSite);
+                            if (existingSiteInst != null) {
+                                break;
+                            }
+                        }
+                    } else if (siteType == SiteTypeEnum.RAMB181) { // UltraScale+
+                        // Check that RAMB36 is free
+                        for (Site alternateSite : newTile.getSites()) {
+                            if (alternateSite.getSiteTypeEnum() != SiteTypeEnum.RAMBFIFO36) {
+                                continue;
+                            }
+                            existingSiteInst = design.getSiteInstFromSite(alternateSite);
+                            break;
+                        }
+                    }
+                }
+            }
 
             if (newSite == null || existingSiteInst != null) {
                 //MessageGenerator.briefError("ERROR: No matching site found." +

test/src/com/xilinx/rapidwright/design/TestModuleInst.java

@@ -23,6 +23,7 @@
 
 package com.xilinx.rapidwright.design;
 
+import com.xilinx.rapidwright.device.Device;
 import com.xilinx.rapidwright.device.PIP;
 import com.xilinx.rapidwright.device.Site;
 import com.xilinx.rapidwright.device.Tile;
@@ -34,6 +35,7 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.junit.jupiter.params.provider.ValueSource;
 
 import java.util.HashSet;
@@ -247,4 +249,44 @@ public void testPlaceWithDepopulatedNodes() {
         Assertions.assertEquals(70560, validAnchorSites.size());
 
     }
+
+    @ParameterizedTest
+    @CsvSource({
+            "RAMB36E2,RAMB36_X1Y0/RAMB36E2",                // Regular RAMB36 conflict
+            "RAMB18E2,RAMB18_X1Y0/RAMB18E2_L",              // Regular RAMB18 (lower) conflict
+            "RAMB18E2,RAMB18_X1Y1/RAMB18E2_U",              // Regular RAMB18 (upper) conflict
+            "FIFO18E2,RAMB18_X1Y0/BELI_FIFO18E2_FIFO18E2",  // Regular FIFO18 (lower) conflict
+    })
+    public void testPlaceChecksBRAM(String unisim, String location) {
+        Design design = RapidWrightDCP.loadDCP("picoblaze_ooc_X10Y235.dcp");
+        Device device = design.getDevice();
+
+        // Unroute partially routed clock that cannot be relocated
+        design.getNet("clk").unroute();
+
+        Design emptyDesign = new Design("emptyDesign", design.getPartName());
+        Module module = new Module(design, false);
+        design = null;
+
+        ModuleInst mi = emptyDesign.createModuleInst("inst", module);
+        // Check placement successful
+        boolean skipIncompatible = false;
+        boolean allowOverlap = false;
+        Site newAnchor = device.getSite("SLICE_X16Y2");
+        Assertions.assertTrue(mi.place(newAnchor, skipIncompatible, allowOverlap));
+        mi.unplace();
+
+        // Place a cell there
+        Cell cell = emptyDesign.createAndPlaceCell("test_ram", Unisim.valueOf(unisim), location);
+        SiteInst si = cell.getSiteInst();
+        Assertions.assertNotNull(si);
+
+        // Check conflict is detected
+        Assertions.assertFalse(mi.place(newAnchor, skipIncompatible, allowOverlap));
+        Assertions.assertFalse(mi.isPlaced());
+
+        // Check conflict is cleared
+        emptyDesign.unplaceDesign();
+        Assertions.assertTrue(mi.place(newAnchor, skipIncompatible, allowOverlap));
+    }
 }