diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -1491,6 +1491,9 @@
       }
 
     bool hasSubcomp = !xbox.subcomponent().empty();
+    if (!xbox.substr().empty())
+      TODO(loc, "codegen of fir.embox with substring");
+
     mlir::Value stepExpr;
     if (hasSubcomp) {
       // We have a subcomponent. The step value needs to be the number of
@@ -1550,9 +1553,10 @@
         // denormalized descriptors.
         if (isaPointerOrAllocatable || !normalizedLowerBound(xbox)) {
           lb = one;
-          // If there is a shifted origin and this is not a normalized
-          // descriptor then use the value from the shift op as the lower bound.
-          if (hasShift) {
+          // If there is a shifted origin, and no fir.slice, and this is not
+          // a normalized descriptor then use the value from the shift op as
+          // the lower bound.
+          if (hasShift && !(hasSlice || hasSubcomp)) {
             lb = operands[shiftOffset];
             auto extentIsEmpty = rewriter.create<mlir::LLVM::ICmpOp>(
                 loc, mlir::LLVM::ICmpPredicate::eq, extent, zero);
diff --git a/flang/test/Fir/convert-to-llvm.fir b/flang/test/Fir/convert-to-llvm.fir
--- a/flang/test/Fir/convert-to-llvm.fir
+++ b/flang/test/Fir/convert-to-llvm.fir
@@ -1743,9 +1743,7 @@
 // CHECK:         %[[EXTENT2:.*]] = llvm.sdiv %[[EXTENT1]], %[[C0]]  : i64
 // CHECK:         %[[EXTENT_CMP:.*]] = llvm.icmp "sgt" %[[EXTENT2]], %[[ZERO]] : i64
 // CHECK:         %[[EXTENT:.*]] = llvm.select %[[EXTENT_CMP]], %[[EXTENT2]], %[[ZERO]] : i1, i64
-// CHECK:         %[[EXTENT_CMP_2:.*]] = llvm.icmp "eq" %[[EXTENT]], %[[ZERO]] : i64
-// CHECK:         %[[LOWER:.*]] = llvm.select %[[EXTENT_CMP_2]], %[[ONE]], %[[C0]] : i1, i64
-// CHECK:         %[[BOX7:.*]] = llvm.insertvalue %[[LOWER]], %[[BOX6]][7 : i32, 0 : i32, 0 : i32] : !llvm.struct<(ptr<i32>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<1 x array<3 x i64>>)>
+// CHECK:         %[[BOX7:.*]] = llvm.insertvalue %[[ONE]], %[[BOX6]][7 : i32, 0 : i32, 0 : i32] : !llvm.struct<(ptr<i32>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<1 x array<3 x i64>>)>
 // CHECK:         %[[BOX8:.*]] = llvm.insertvalue %[[EXTENT]], %[[BOX7]][7 : i32, 0 : i32, 1 : i32] : !llvm.struct<(ptr<i32>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<1 x array<3 x i64>>)>
 // CHECK:         %[[STRIDE:.*]] = llvm.mul %[[ELEM_LEN_I64]], %[[C0]]  : i64
 // CHECK:         %[[BOX9:.*]] = llvm.insertvalue %[[STRIDE]], %[[BOX8]][7 : i32, 0 : i32, 2 : i32] : !llvm.struct<(ptr<i32>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<1 x array<3 x i64>>)>
@@ -1844,9 +1842,7 @@
 // CHECK:         %[[EXTENT2:.*]] = llvm.sdiv %[[EXTENT1]], %[[C1]]  : i64
 // CHECK:         %[[EXTENT_CMP:.*]] = llvm.icmp "sgt" %[[EXTENT2]], %[[ZERO]] : i64
 // CHECK:         %[[EXTENT:.*]] = llvm.select %[[EXTENT_CMP]], %[[EXTENT2]], %[[ZERO]] : i1, i64
-// CHECK:         %[[EXTENT_CMP_2:.*]] = llvm.icmp "eq" %[[EXTENT]], %[[ZERO]] : i64
-// CHECK:         %[[SH1B:.*]] = llvm.select %[[EXTENT_CMP_2]], %[[ONE]], %[[SH1]] : i1, i64
-// CHECK:         %[[BOX7:.*]] = llvm.insertvalue %[[SH1B]], %[[BOX6]][7 : i32, 0 : i32, 0 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
+// CHECK:         %[[BOX7:.*]] = llvm.insertvalue %[[ONE]], %[[BOX6]][7 : i32, 0 : i32, 0 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
 // CHECK:         %[[BOX8:.*]] = llvm.insertvalue %[[EXTENT]], %[[BOX7]][7 : i32, 0 : i32, 1 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
 // CHECK:         %[[STRIDE:.*]] = llvm.mul %[[ELEM_LEN_I64]], %[[C1]]  : i64
 // CHECK:         %[[BOX9:.*]] = llvm.insertvalue %[[STRIDE]], %[[BOX8]][7 : i32, 0 : i32, 2 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
@@ -1860,9 +1856,7 @@
 // CHECK:         %[[EXT_SDIV:.*]] = llvm.sdiv %[[EXT_ADD]], %[[C1]]  : i64
 // CHECK:         %[[EXT_ICMP:.*]] = llvm.icmp "sgt" %[[EXT_SDIV]], %[[ZERO]] : i64
 // CHECK:         %[[EXT_SELECT:.*]] = llvm.select %[[EXT_ICMP]], %[[EXT_SDIV]], %[[ZERO]] : i1, i64
-// CHECK:         %[[EXT_ICMP_2:.*]] = llvm.icmp "eq" %[[EXT_SELECT]], %[[ZERO]] : i64
-// CHECK:         %[[SH2B:.*]] = llvm.select %[[EXT_ICMP_2]], %[[ONE]], %[[SH2]] : i1, i64
-// CHECK:         %[[BOX10:.*]] = llvm.insertvalue %[[SH2B]], %[[BOX9]][7 : i32, 1 : i32, 0 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
+// CHECK:         %[[BOX10:.*]] = llvm.insertvalue %[[ONE]], %[[BOX9]][7 : i32, 1 : i32, 0 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
 // CHECK:         %[[BOX11:.*]] = llvm.insertvalue %[[EXT_SELECT]], %[[BOX10]][7 : i32, 1 : i32, 1 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>
 // CHECK:         %[[STRIDE_MUL:.*]] = llvm.mul %[[PREV_DIM]], %[[C1]]  : i64
 // CHECK:         %[[BOX12:.*]] = llvm.insertvalue %[[STRIDE_MUL]], %[[BOX11]][7 : i32, 1 : i32, 2 : i32] : !llvm.struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, array<2 x array<3 x i64>>)>