Merge remote-tracking branch 'upstream/master' into bugfix/queue-compare

verilator · wsnyder · May 20, 2025 · Apr 19, 2025 · Apr 19, 2025 · Apr 19, 2025
commit c512f7a333435d7a28dba44e6cdcba2457f415f8
diff --git a/src/V3Slice.cpp b/src/V3Slice.cpp
@@ -316,13 +316,27 @@ class SliceVisitor final : public VNVisitor {
         const AstNodeDType* const fromDtp = nodep->lhsp()->dtypep()->skipRefp();
         if (const AstUnpackArrayDType* const adtypep = VN_CAST(fromDtp, UnpackArrayDType)) {
             AstNodeBiop* logp = nullptr;
+
             const int elements = adtypep->rangep()->elementsConst();
             for (int elemIdx = 0; elemIdx < elements; ++elemIdx) {
                 // EQ(a,b) -> LOGAND(EQ(ARRAYSEL(a,0), ARRAYSEL(b,0)), ...[1])
-                AstNodeBiop* const clonep
-                    = VN_AS(nodep->cloneType(cloneAndSel(nodep->lhsp(), elements, elemIdx),
-                                             cloneAndSel(nodep->rhsp(), elements, elemIdx)),
-                            NodeBiop);
+                // Original node is replaced, so it is safe to copy it one time even if it is
+                // impure.
+                AstNodeBiop* const clonep = VN_AS(
+                    nodep->cloneType(cloneAndSel(nodep->lhsp(), elements, elemIdx, elemIdx != 0),
+                                     cloneAndSel(nodep->rhsp(), elements, elemIdx, elemIdx != 0)),
+                    NodeBiop);
+                if (elemIdx == 0) {
+                    nodep->foreach([this](AstExprStmt* const exprp) {
+                        // Result expression is always evaluated to the same value, so the
+                        // statements can be removed once they were included in the expression
+                        // created for the 1st element.
+                        AstNodeExpr* const resultp = exprp->resultp()->unlinkFrBack();
+                        exprp->replaceWith(resultp);
+                        VL_DO_DANGLING(pushDeletep(exprp), exprp);
+                    });
+                }
+
                 if (!logp) {
                     logp = clonep;
                 } else {