diff --git a/lib/Solver/BitwuzlaBuilder.cpp b/lib/Solver/BitwuzlaBuilder.cpp
index 57d5f188f1..2762afb98a 100644
--- a/lib/Solver/BitwuzlaBuilder.cpp
+++ b/lib/Solver/BitwuzlaBuilder.cpp
@@ -619,6 +619,21 @@ Term BitwuzlaBuilder::constructActual(ref<Expr> e, int *width_out) {
     Term src = castToFloat(construct(ce->src, &srcWidth));
     *width_out = ce->getWidth();
     FPCastWidthAssert(width_out, "Invalid FPToUI width");
+    auto fp_widths = getFloatSortFromBitWidth(srcWidth);
+    Term maxBound = ctx->mk_term(
+        Kind::FP_LEQ,
+        {src, ctx->mk_term(Kind::FP_TO_FP_FROM_UBV,
+                           {getRoundingModeSort(ce->roundingMode),
+                            ctx->mk_bv_ones(ctx->mk_bv_sort(*width_out))},
+                           {fp_widths.first, fp_widths.second})});
+    sideConstraints.push_back(maxBound);
+    Term minBound = ctx->mk_term(
+        Kind::FP_GEQ,
+        {src, ctx->mk_term(Kind::FP_TO_FP_FROM_UBV,
+                           {getRoundingModeSort(ce->roundingMode),
+                            ctx->mk_bv_zero(ctx->mk_bv_sort(*width_out))},
+                           {fp_widths.first, fp_widths.second})});
+    sideConstraints.push_back(minBound);
     return ctx->mk_term(Kind::FP_TO_UBV,
                         {getRoundingModeSort(ce->roundingMode), src},
                         {ce->getWidth()});
@@ -630,6 +645,21 @@ Term BitwuzlaBuilder::constructActual(ref<Expr> e, int *width_out) {
     Term src = castToFloat(construct(ce->src, &srcWidth));
     *width_out = ce->getWidth();
     FPCastWidthAssert(width_out, "Invalid FPToSI width");
+    auto fp_widths = getFloatSortFromBitWidth(srcWidth);
+    Term maxBound = ctx->mk_term(
+        Kind::FP_LEQ,
+        {src, ctx->mk_term(Kind::FP_TO_FP_FROM_SBV,
+                           {getRoundingModeSort(ce->roundingMode),
+                            ctx->mk_bv_max_signed(ctx->mk_bv_sort(*width_out))},
+                           {fp_widths.first, fp_widths.second})});
+    sideConstraints.push_back(maxBound);
+    Term minBound = ctx->mk_term(
+        Kind::FP_GEQ,
+        {src, ctx->mk_term(Kind::FP_TO_FP_FROM_SBV,
+                           {getRoundingModeSort(ce->roundingMode),
+                            ctx->mk_bv_min_signed(ctx->mk_bv_sort(*width_out))},
+                           {fp_widths.first, fp_widths.second})});
+    sideConstraints.push_back(minBound);
     return ctx->mk_term(Kind::FP_TO_SBV,
                         {getRoundingModeSort(ce->roundingMode), src},
                         {ce->getWidth()});
diff --git a/lib/Solver/Z3BitvectorBuilder.cpp b/lib/Solver/Z3BitvectorBuilder.cpp
index 1491ac9cc6..9127f4848d 100644
--- a/lib/Solver/Z3BitvectorBuilder.cpp
+++ b/lib/Solver/Z3BitvectorBuilder.cpp
@@ -419,6 +419,21 @@ Z3ASTHandle Z3BitvectorBuilder::constructActual(ref<Expr> e, int *width_out) {
     Z3ASTHandle src = castToFloat(construct(ce->src, &srcWidth));
     *width_out = ce->getWidth();
     FPCastWidthAssert(width_out, "Invalid FPToUI width");
+    auto fp_width = getFloatSortFromBitWidth(srcWidth);
+    Z3ASTHandle maxBound = Z3ASTHandle(
+        Z3_mk_fpa_leq(
+            ctx, src,
+            Z3_mk_fpa_to_fp_unsigned(ctx, getRoundingModeSort(ce->roundingMode),
+                                     bvMinusOne(*width_out), fp_width)),
+        ctx);
+    sideConstraints.push_back(maxBound);
+    Z3ASTHandle minBound = Z3ASTHandle(
+        Z3_mk_fpa_geq(
+            ctx, src,
+            Z3_mk_fpa_to_fp_unsigned(ctx, getRoundingModeSort(ce->roundingMode),
+                                     bvZero(*width_out), fp_width)),
+        ctx);
+    sideConstraints.push_back(minBound);
     return Z3ASTHandle(Z3_mk_fpa_to_ubv(ctx,
                                         getRoundingModeSort(ce->roundingMode),
                                         src, *width_out),
@@ -431,6 +446,23 @@ Z3ASTHandle Z3BitvectorBuilder::constructActual(ref<Expr> e, int *width_out) {
     Z3ASTHandle src = castToFloat(construct(ce->src, &srcWidth));
     *width_out = ce->getWidth();
     FPCastWidthAssert(width_out, "Invalid FPToSI width");
+    auto fp_width = getFloatSortFromBitWidth(srcWidth);
+    Z3ASTHandle smax = Z3ASTHandle(
+        Z3_mk_concat(ctx, bvZero(1), bvMinusOne(*width_out - 1)), ctx);
+    Z3ASTHandle fpsmax = Z3ASTHandle(
+        Z3_mk_fpa_to_fp_signed(ctx, getRoundingModeSort(ce->roundingMode), smax,
+                               fp_width),
+        ctx);
+    Z3ASTHandle maxBound = Z3ASTHandle(Z3_mk_fpa_leq(ctx, src, fpsmax), ctx);
+    sideConstraints.push_back(maxBound);
+    Z3ASTHandle smin =
+        Z3ASTHandle(Z3_mk_concat(ctx, bvOne(1), bvZero(*width_out - 1)), ctx);
+    Z3ASTHandle fpsmin = Z3ASTHandle(
+        Z3_mk_fpa_to_fp_signed(ctx, getRoundingModeSort(ce->roundingMode), smin,
+                               fp_width),
+        ctx);
+    Z3ASTHandle minBound = Z3ASTHandle(Z3_mk_fpa_geq(ctx, src, fpsmin), ctx);
+    sideConstraints.push_back(maxBound);
     return Z3ASTHandle(Z3_mk_fpa_to_sbv(ctx,
                                         getRoundingModeSort(ce->roundingMode),
                                         src, *width_out),