Address review feedback

Author: andykaylor

clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp

@@ -1178,11 +1178,18 @@ static mlir::Value emitPointerArithmetic(CIRGenFunction &cgf,
   mlir::Value index = op.rhs;
   Expr *indexOperand = expr->getRHS();
 
-  // In a subtraction, the LHS is always the pointer.
+  // In the case of subtraction, the FE has ensured that the LHS is always the
+  // pointer. However, addition can have the pointer on either side. We will
+  // always have a pointer operand and an integer operand, so if the LHS wasn't
+  // a pointer, we need to swap our values.
   if (!isSubtraction && !mlir::isa<cir::PointerType>(pointer.getType())) {
     std::swap(pointer, index);
     std::swap(pointerOperand, indexOperand);
   }
+  assert(mlir::isa<cir::PointerType>(pointer.getType()) &&
+         "Need a pointer operand");
+  assert(mlir::isa<cir::IntType>(index.getType()) &&
+         "Need an integer operand");
 
   // Some versions of glibc and gcc use idioms (particularly in their malloc
   // routines) that add a pointer-sized integer (known to be a pointer value)

clang/test/CIR/CodeGen/pointers.cpp

@@ -28,6 +28,10 @@ void foo(int *iptr, char *cptr, unsigned ustride) {
   // CHECK: %[[#NEGSTRIDE:]] = cir.unary(minus, %[[#SIGNSTRIDE]]) : !s32i, !s32i
   // CHECK: cir.ptr_stride(%{{.+}} : !cir.ptr<!s32i>, %[[#NEGSTRIDE]] : !s32i), !cir.ptr<!s32i>
 
+  4 + iptr;
+  // CHECK: %[[#STRIDE:]] = cir.const #cir.int<4> : !s32i
+  // CHECK: cir.ptr_stride(%{{.+}} : !cir.ptr<!s32i>, %[[#STRIDE]] : !s32i), !cir.ptr<!s32i>
+
   iptr++;
   // CHECK: %[[#STRIDE:]] = cir.const #cir.int<1> : !s32i
   // CHECK: cir.ptr_stride(%{{.+}} : !cir.ptr<!s32i>, %[[#STRIDE]] : !s32i), !cir.ptr<!s32i>