Internals: Favor std::swap. No functional change.

src/V3AstAttr.h

@@ -1482,11 +1482,7 @@ public:
     ~VNumRange() = default;
     // MEMBERS
     void init(int hi, int lo, bool ascending) {
-        if (lo > hi) {
+        if (lo > hi) std::swap(hi, lo);
-            const int t = hi;
-            hi = lo;
-            lo = t;
-        }
         m_left = ascending ? lo : hi;
         m_right = ascending ? hi : lo;
         m_ranged = true;

src/V3Width.cpp

@@ -1185,11 +1185,7 @@ class WidthVisitor final : public VNVisitor {
             if (const AstUnpackArrayDType* const adtypep = VN_CAST(fromDtp, UnpackArrayDType)) {
                 frommsb = adtypep->hi();
                 fromlsb = adtypep->lo();
-                if (fromlsb > frommsb) {
+                if (fromlsb > frommsb) std::swap(frommsb, fromlsb);
-                    const int t = frommsb;
-                    frommsb = fromlsb;
-                    fromlsb = t;
-                }
                 // However, if the lsb<0 we may go negative, so need more bits!
                 if (fromlsb < 0) frommsb += -fromlsb;
                 nodep->dtypeFrom(adtypep->subDTypep());  // Need to strip off array reference

src/V3WidthSel.cpp

@@ -448,21 +448,15 @@ class WidthSelVisitor final : public VNVisitor {
                         adtypep,
                         "Array extraction with width miscomputed " << adtypep->width() << "/"
                                                                    << fromRange.elements());
-            if (fromRange.ascending()) {
+            // Below code assumes descending bit range; just works out if we swap
-                // Below code assumes descending bit range; just works out if we swap
+            if (fromRange.ascending()) std::swap(msb, lsb);
-                const int x = msb;
-                msb = lsb;
-                lsb = x;
-            }
             if (lsb > msb) {
                 nodep->v3warn(
                     SELRANGE,
                     "[" << msb << ":" << lsb
                         << "] Slice range has ascending bit ordering, perhaps you wanted [" << lsb
                         << ":" << msb << "]");
-                const int x = msb;
+                std::swap(msb, lsb);
-                msb = lsb;
-                lsb = x;
             }
             const int elwidth = adtypep->width() / fromRange.elements();
             AstSel* const newp
@@ -477,21 +471,15 @@ class WidthSelVisitor final : public VNVisitor {
             nodep->replaceWith(newp);
             VL_DO_DANGLING(pushDeletep(nodep), nodep);
         } else if (VN_IS(ddtypep, BasicDType)) {
-            if (fromRange.ascending()) {
+            // Below code assumes descending bit range; just works out if we swap
-                // Below code assumes descending bit range; just works out if we swap
+            if (fromRange.ascending()) std::swap(msb, lsb);
-                const int x = msb;
-                msb = lsb;
-                lsb = x;
-            }
             if (lsb > msb) {
                 nodep->v3warn(
                     SELRANGE,
                     "[" << msb << ":" << lsb
                         << "] Slice range has ascending bit ordering, perhaps you wanted [" << lsb
                         << ":" << msb << "]");
-                const int x = msb;
+                std::swap(msb, lsb);
-                msb = lsb;
-                lsb = x;
             }
             AstSel* const newp = new AstSel{nodep->fileline(), fromp, newSubLsbOf(lsbp, fromRange),
                                             msb + 1 - lsb};
@@ -508,9 +496,7 @@ class WidthSelVisitor final : public VNVisitor {
                     "[" << msb << ":" << lsb
                         << "] Slice range has ascending bit ordering, perhaps you wanted [" << lsb
                         << ":" << msb << "]");
-                const int x = msb;
+                std::swap(msb, lsb);
-                msb = lsb;
-                lsb = x;
             }
             AstSel* const newp = new AstSel{nodep->fileline(), fromp, newSubLsbOf(lsbp, fromRange),
                                             msb + 1 - lsb};

test_regress/t/t_param_sel_range1_bad.out

@@ -1,5 +1,5 @@
-%Warning-SELRANGE: t/t_param_sel_range.v:41:33: Selection index out of range: 7:7 outside 4:0
+%Warning-SELRANGE: t/t_param_sel_range1.v:41:33: Selection index out of range: 7:7 outside 4:0
-                                              : ... note: In instance 't.u2'
+                                               : ... note: In instance 't.u2'
    41 |           else r_rst[i] <= r_rst[i-1];   
       |                                 ^
                    ... For warning description see https://verilator.org/warn/SELRANGE?v=latest

test_regress/t/t_param_sel_range1_bad.py

@@ -10,7 +10,7 @@
 import vltest_bootstrap
 
 test.scenarios('linter')
-test.top_filename = "t/t_param_sel_range.v"
+test.top_filename = "t/t_param_sel_range1.v"
 
 test.lint(fails=True, expect_filename=test.golden_filename)