nowrshmsk: Check for stride==0

log2(0) returns -inf, which gives undefined behaviour when casting to an int.  So catch the case when it's 0 just set the width to 0.

frontends/ast/simplify.cc

@@ -2936,7 +2936,10 @@ bool AstNode::simplify(bool const_fold, int stage, int width_hint, bool sign_hin
 					lsb_expr->children[stride_ix]->detectSignWidth(stride_width, stride_sign);
 					max_width = std::max(i_width, stride_width);
 					// Stride width calculated from actual stride value.
-					stride_width = std::ceil(std::log2(std::abs(stride)));
+					if (stride == 0)
+						stride_width = 0;
+					else
+						stride_width = std::ceil(std::log2(std::abs(stride)));
 
 					if (i_width + stride_width > max_width) {
 						// For (truncated) i*stride to be within the range of dst, the following must hold: